CH-2 Heredity and Environment – Understanding Human Development : Exam Guide

Chapter 2 - Heredity and Environment 1. If you were to compare the DNA of any two unrelated people, about what percent of their DNA would be identical? a. 25% b. 50% c. 99.9% d. 100% Answer: c Rationale: The correct answer is c. 99.9%. While it might seem that unrelated individuals would have significantly different DNA, the reality is that humans share approximately 99.9% of their DNA sequence with each other. This high degree of genetic similarity is due to the fact that humans are a single species, and the vast majority of our DNA is shared among individuals. 2. Which of the following disorders occurs only when the gene involved is inherited from the mother and not the father? a. Prader-Willi syndrome b. Angelman syndrome c. Fragile X syndrome d. Down syndrome Answer: a Rationale: The correct answer is a. Prader-Willi syndrome. Prader-Willi syndrome occurs due to the loss of certain genes on the paternal chromosome 15. If these genes are missing or inactive on the paternal chromosome, the individual will have Prader-Willi syndrome. However, if the same genes are missing or inactive on the maternal chromosome 15, it leads to a different disorder called Angelman syndrome. 3. Operant conditioning is especially likely to be involved in the development of: a. phobias b. excessive salivation c. habituation d. habits Answer: d Rationale: The correct answer is d. habits. Operant conditioning, a form of learning in which behavior is strengthened or weakened by the consequences that follow it, is especially relevant in the development of habits. Through reinforcement or punishment, individuals learn to repeat or avoid certain behaviors, leading to the formation of habits. 4. Suppose that a human female is accidentally exposed to a poison at one of four different points in development. If the effect of the poison is that it interferes with meiosis, at which point in the lifespan would we expect it to have the most disruptive effect? a. in the prenatal period, since this is when ova are forming b. in the first year after birth, since this is when brain growth is most rapid c. during early adulthood, since this is when conception of a child is most likely to happen d. in older adulthood, since body cells are most vulnerable at the end of the lifespan Answer: a Rationale: The correct answer is a. in the prenatal period, since this is when ova are forming. Meiosis, the process by which germ cells (ova or sperm) are formed, occurs during prenatal development. If a poison interferes with meiosis, it would have the most disruptive effect during the prenatal period when ova are being formed. Interference with meiosis during this critical stage could lead to genetic abnormalities in the offspring. 5. If different members of the family experience quite different environments, this would be reflected in: a. a larger shared environment b. a larger nonshared environment c. a harsher developmental niche d. a challenge for self-concept development Answer: b Rationale: The correct answer is b. a larger nonshared environment. The shared environment refers to environmental factors that family members have in common, such as parental discipline practices or socioeconomic status. The nonshared environment refers to environmental factors that are unique to each individual within the family, such as peer relationships, personal experiences, or random events. If different family members experience quite different environments, it would be reflected in a larger nonshared environment, as each individual's experiences would contribute more to their development than shared family experiences. 6. Which of the following is MOST likely to be experienced as a normative influence? a. retirement b. career change c. illness d. moving to a new community Answer: a Rationale: The correct answer is a. retirement. A normative influence refers to a developmental event or transition that occurs at a predictable time for most individuals within a particular culture or society. Retirement is an example of a normative influence because it typically occurs around a certain age range and is expected for individuals who reach a certain stage of their career or lifespan. 7. Suppose that a disease is inherited. Your mother has the disease, your father does not, and you have a very minor case of the disease which lies somewhere in between your mother’s and father’s situation. In this case, we would know that the alleles that determine this trait: a. are recessive b. are dominant c. are codominant d. are heterozygous Answer: c Rationale: The correct answer is c. are codominant. In codominance, both alleles of a gene are fully expressed, resulting in a phenotype that shows characteristics of both alleles. In this scenario, since you have a phenotype that lies between your mother's and father's phenotypes, it indicates that the alleles for the trait are codominant. 8. Workers in Dr. Garcia’s lab first obtain tumor cells from patients with cancer. They then remove the DNA from the tumor cell nuclei and use enzymes to segment the DNA strands into sections. Finally, they insert the DNA sections in which they are interested into “host” bacteria cells, where the DNA can be reproduced for later use. Dr. Garcia’s lab is engaged in work involving: a. behavior genetics b. recombinant technology c. cryogenics d. autosomal transmission Answer: b Rationale: The correct answer is b. recombinant technology. The described process involves recombinant DNA technology, where specific DNA sections from tumor cells are isolated, manipulated, and inserted into host bacteria cells. This technology allows researchers to study and manipulate specific genes or DNA sequences, facilitating various applications in biotechnology, such as gene cloning, gene therapy, and the production of recombinant proteins. 9. Dr. Smith studies a group of 1,000 people who have schizophrenia and who also have identical twins. He finds that 47% of the identical twins also develop this disease. The type of statistical information Dr. Smith’s study reveals is called: a. concordance b. an H-E (Heredity-Environment) Index c. a genetic-based percentage d. analysis of variance Answer: a Rationale: The correct answer is a. concordance. Concordance refers to the degree of similarity or agreement between pairs of individuals with respect to a particular trait or condition. In this case, Dr. Smith's study reveals the concordance rate for schizophrenia among identical twins, indicating the percentage of twins who both develop the disease. A higher concordance rate suggests a stronger genetic contribution to the trait being studied. 10. Patty doesn’t want to hang around with people from the other side of town because she says they are “weird.” Patty’s behavior best reflects the concept involved in: a. ethnocentrism b. self-efficacy c. normative age-graded influences d. normative history-graded influences Answer: a Rationale: The correct answer is a. ethnocentrism. Ethnocentrism refers to the tendency to view one's own cultural group as superior to others and to judge other cultures based on the standards and values of one's own culture. Patty's reluctance to associate with people from a different part of town because she perceives them as "weird" reflects a bias rooted in her own cultural perspective, indicating ethnocentric attitudes. Ethnocentrism can lead to prejudice, discrimination, and social conflict. 1. The term used to describe alternate versions of the same gene is: a. alleles b. chromosomes c. autosomes d. gametes Answer: a Rationale: The correct answer is a. alleles. Alleles are different forms or variations of a gene that occupy the same locus (position) on a chromosome. Individuals inherit two alleles for each gene, one from each parent, which may be the same (homozygous) or different (heterozygous). 2. The extent to which a trait is inherited versus acquired through interactions with the environment defines the concept of: a. heritability b. genetic predisposition c. genetic engineering d. concordance Answer: a Rationale: The correct answer is a. heritability. Heritability refers to the proportion of variability in a trait within a population that is attributable to genetic factors. It indicates the degree to which individual differences in a trait are due to genetic variation rather than environmental influences. Heritability estimates range from 0 to 1, where 0 indicates no genetic influence and 1 indicates that all variability is due to genetic factors. 3. The tendency to assume that one’s own cultural beliefs are normal and those of others are abnormal is referred to as: a. cohesion b. socialization c. ethnocentrism d. indoctrination Answer: c Rationale: The correct answer is c. ethnocentrism. Ethnocentrism is the tendency to judge other cultures by the standards and values of one's own culture, often resulting in the belief that one's own cultural beliefs, practices, and norms are superior or more correct than those of other cultures. It can lead to prejudice, discrimination, and conflict between different cultural groups. 4. Color blindness is a sex-linked trait. As such, if a child is color blind, we can be assured that the child’s genotype includes: a. a recessive gene on the X chromosome inherited from his mother b. a dominant gene on the X chromosome inherited from his mother c. a recessive gene on the Y chromosome inherited from his father d. a dominant gene on the X chromosome inherited from his father Answer: a Rationale: The correct answer is a. a recessive gene on the X chromosome inherited from his mother. Color blindness is a sex-linked recessive trait, meaning the gene responsible for color blindness is located on the X chromosome. Since males have only one X chromosome (inherited from their mother) and one Y chromosome (inherited from their father), they express the trait if they inherit the recessive allele for color blindness from their mother. 5. Which of the following syndromes occurs only in females? a. Down syndrome b. Turner’s syndrome c. Klinefelter's syndrome d. Fragile X syndrome Answer: b Rationale: The correct answer is b. Turner’s syndrome. Turner's syndrome is a genetic disorder that occurs in females and is characterized by the partial or complete absence of one X chromosome. Individuals with Turner's syndrome typically have short stature, infertility, and certain physical features such as a webbed neck and low-set ears. The other options, Down syndrome, Klinefelter's syndrome, and Fragile X syndrome, can occur in both males and females. 6. The key to understanding how classical conditioning works is to recognize that it involves the _________ of what will come. a. reinforcement b. punishment c. prediction d. repression Answer: c Rationale: The correct answer is c. prediction. Classical conditioning involves learning to associate a neutral stimulus (conditioned stimulus) with an unconditioned stimulus that naturally produces a reflexive response. Through repeated pairings, the neutral stimulus becomes a predictor of the unconditioned stimulus and elicits a conditioned response. Therefore, the key to understanding classical conditioning is recognizing that it involves the prediction of what will come based on the association between stimuli. 7. Anne mentions that her cousin has a congenital anomaly. You would know that this is sometimes also referred to as: a. a sex-linked trait b. a birth defect c. an autosomal disorder d. a heterozygous trait Answer: b Rationale: The correct answer is b. a birth defect. A congenital anomaly, as mentioned in the question, refers to a physical or structural abnormality present at birth, which is often referred to as a birth defect. These anomalies can range from minor to severe and may be caused by genetic factors, environmental influences, or a combination of both. 8. Olaf has been diagnosed with Klinefelter's syndrome. What is his chromosomal pattern? a. XO b. XY c. XXY d. XYY Answer: c Rationale: The correct answer is c. XXY. Klinefelter's syndrome is a genetic disorder characterized by the presence of an extra X chromosome in males. Typically, males have an XY chromosomal pattern, but individuals with Klinefelter's syndrome have an additional X chromosome, resulting in a chromosomal pattern of XXY. 9. While sitting in a quiet waiting room, Ronnie at first is quite distracted by the clicking sound made by an old clock ticking away the seconds. However, after a few minutes, he no longer notices the ticking. This example best highlights the concept involved in: a. concordance b. classical conditioning c. habituation d. social learning Answer: c Rationale: The correct answer is c. habituation. Habituation is the process by which an individual becomes accustomed to or desensitized to a repeated or constant stimulus over time. In the given scenario, Ronnie initially notices the clicking sound of the clock, but as time passes and the sound continues without any change or consequence, he habituates to it and no longer pays attention to it. 10. Many individuals who grew up during the Great Depression were so devastated by the collapse of the economy that they became distrustful of depositing large sums of money in banks. The Great Depression would best be considered a: a. normative, age-graded influence b. normative, history-graded influence c. nonnormative influence d. normative, economic-graded influence Answer: b Rationale: The correct answer is b. normative, history-graded influence. A normative, history-graded influence refers to an event or circumstance that impacts a large group of people within a specific historical period, shaping their experiences and development. The Great Depression was a significant historical event that profoundly affected individuals who lived through it, influencing their attitudes, behaviors, and economic decisions. Therefore, it is best considered a normative, history-graded influence. Multiple Choice questions Molecular Genetics 1. According to the text, the human body contains about how many different types of cells? a. 16 b. 50 c. 200 d. several thousand Answer: c Rationale: The correct answer is c. 200. The human body consists of approximately 200 different types of cells, each specialized for specific functions within various tissues and organs. These cell types include neurons, muscle cells, skin cells, blood cells, and many others, collectively contributing to the complexity and diversity of human physiology. 2. Which of the following parts of the cell provides most of its energy? a. Golgi bodies b. mitochondria c. cytoplasm d. the nucleus Answer: b Rationale: Mitochondria are known as the powerhouse of the cell because they are the primary sites of cellular respiration, a process that generates adenosine triphosphate (ATP), the molecule used by cells as a source of energy. Within the mitochondria, the process of oxidative phosphorylation occurs, which produces the majority of ATP through the electron transport chain and ATP synthase. Therefore, option b, mitochondria, provide most of the cell's energy. 3. If a researcher wanted to extract the DNA from a cell, she should look for it in the cell’s: a. nucleus b. mitochondria c. cytoplasm d. cell membrane Answer: a Rationale: The cell’s nucleus, which also is surrounded by a porous membrane, contains most of the deoxyribonucleic acid (DNA), which contains the genetic instructions that direct growth and development. 4. In building a house, carpenters look for instructions on a blueprint, which includes all of the information needed to construct the house. Comparing a house to a human cell, the part of the cell that contains the “blueprint” would be: a. the Golgi bodies b. the cell membrane c. the mitochondria d. the nucleus Answer: d Rationale: The cell’s nucleus, which also is surrounded by a porous membrane, contains most of the deoxyribonucleic acid (DNA), which contains the genetic instructions that direct growth and development. 5. DNA refers to: a. di-nucleic antibody b. duonucleic acid c. deoxyribonucleic acid d. dynonucleic antigen Answer: c Rationale: The correct answer is c. deoxyribonucleic acid. DNA (deoxyribonucleic acid) is a molecule that carries the genetic instructions necessary for the growth, development, functioning, and reproduction of all known living organisms and many viruses. It consists of two long chains of nucleotides twisted into a double helix and carries the genetic information in the form of genes. 6. The structure of DNA consists of a long molecule that looks somewhat like a ladder that has been “twisted.” The shape of the DNA molecule is referred to as: a. the double rope b. the twisted rope c. the double helix d. the Golgi apparatus Answer: c Rationale: DNA is a highly complex macromolecule: It is made up of many smaller molecules that are arranged in the shape of a twisted ladder called a double helix. 7. Which of the following statements about DNA is true? a. The DNA molecule is circular, with the nucleotide bases located in the center of the circle. b. The DNA molecule contains only four different types of bases, regardless of what species is involved. c. The DNA molecule is identical for every known species, and species differences are coded on molecules that lay alongside the DNA. d. The pairing of adenine, thymine, cytosine, and guanine follows a random sequence, with all four base pairs combining with each other an equal percentage of times. Answer: b Rationale: The DNA molecule is elegant in that, regardless of the species, it contains only four types of bases: adenine (A), thymine (T), cytosine (C), and guanine (G). 8. Which of the following is NOT contained in a nucleotide? a. a base molecule b. an enzyme c. a phosphate molecule d. a sugar molecule Answer: b Rationale: The correct answer is b. an enzyme. A nucleotide is composed of three main components: a phosphate molecule, a sugar molecule (deoxyribose in DNA or ribose in RNA), and a nitrogenous base molecule (adenine, thymine, cytosine, or guanine). Enzymes, on the other hand, are proteins that act as biological catalysts to facilitate chemical reactions but are not part of the structure of nucleotides. 9. Suppose you get into an argument about how similar humans and chimpanzees are. One point to consider is that these species share about ________ % of their genes. a. 50 b. 65 c. 85 d. 98 Answer: d Rationale: We share about 98% of our genes with chimpanzees; between two unrelated humans, there is only one tenth of 1% difference in the genes. 10. If you were to compare the DNA of any two unrelated people, about what percent of their DNA would be identical? a. 25% b. 50% c. 99.9% d. 100% Answer: c Rationale: The correct answer is c. 99.9%. While unrelated individuals may have variations in their DNA sequences, they share approximately 99.9% of their DNA. This high degree of genetic similarity is due to the fact that humans are a single species and share a common evolutionary history. 11. Which of the following is NOT one of the ways by which nucleotide bases determine the specific traits contained in the genetic code? a. which side of the ladder the base is on b. the order in which the base pairs are arranged on the ladder c. the total number of base pairs on the ladder d. whether adenine combines with thymine, cytosine, or guanine in the particular DNA strand Answer: d Rationale: Nucleotide bases in DNA determine specific traits primarily through their pairing rules: adenine pairs with thymine (A-T) and cytosine pairs with guanine (C-G). Option d refers to the base pairing rule itself rather than a determinant of specific traits. 12. According to research presented in the text, the genetic locations that are responsible for determining a person’s race: a. are located on chromosome number 18 b. are located on the X chromosome c. are located on many genes, including those in chromosomes 18, 19, and 20 d. are probably unique to each individual, and therefore “race” is not a meaningful concept in a genetic sense Answer: d Rationale: The correct answer is d. According to research, genetic variations responsible for physical traits associated with race are distributed across many genes and are highly individualized. Therefore, the concept of race as defined by genetic markers is not meaningful, as genetic differences among individuals within racial groups are often greater than differences between racial groups. 13. The text suggests that, from a genetic point of view, the concept of race is: a. very important, since there are many genes in the human genome that determine specific race-related traits (such as hair color and eyelid shape) b. largely meaningless, and a better way of thinking about race differences is to consider them as cultural or ethnic differences c. very important, since in humans there are only a handful of genes that code for “race” in our DNA (each corresponding to a difference racial group) d. of some importance, since genes that code for racial characteristics also code for intelligence Answer: b Rationale: The concept of race is often used to categorize people into groups but this categorization becomes largely meaningless when considered from a genetic reference point. Although genes do control the development of characteristics frequently associated with race (e.g., skin color, eye shape, hair color and texture), these traits do not occur as “either–or” features; rather, they are distributed continuously throughout the human population. 14. Dr. Johnson corrects a student who talks about “genetic racial differences” and suggests that a better term to use when talking about genetic differences among defined groups of people would be: a. ethnicity b. genetic physical differences c. nucleotide disparities among individuals d. shared genes Answer: a Rationale: The usage of the term race should be questioned if it suggests that an individual belongs to a genetically defined group. A more appropriate term in a context such as this is ethnicity, which avoids the genetic connotation that race often mistakenly implies and focuses instead on the shared cultural experiences of groups that define their members as similar. 15. A gene is best defined as: a. a nucleotide b. a nucleotide base pair c. a specific segment of DNA d. all of the DNA contained on a specific chromosome Answer: c Rationale: The correct answer is c. a specific segment of DNA. A gene is a functional unit of heredity that is composed of a specific sequence of nucleotides within the DNA molecule. Genes contain instructions for synthesizing proteins, which play essential roles in various biological processes and traits. 16. Current estimates note that the human genome contains about how many genes? a. about 5,000 b. about 25,000 c. about 85,000 d. over a million Answer: b Rationale: The human genome contains approximately 25,000 genes. This estimate has been revised over time, with technological advancements and genome sequencing efforts providing a clearer picture. 17. Compared to earlier estimates about the total number of genes in the human genome, it now appears that there are: a. about 10 times more genes than previously thought b. about twice as many genes as previously thought c. about the same number of genes as was predicted by Watson and Crick in 1954 d. somewhat fewer genes than previously thought Answer: d Rationale: The correct answer is d. somewhat fewer genes than previously thought. Recent advances in genomic research have revealed that the number of protein-coding genes in the human genome is lower than initially estimated. While earlier predictions suggested tens of thousands of genes, it is now believed that there are fewer protein-coding genes, with more emphasis on regulatory elements and non-coding RNA molecules in genome function. 18. A single human gene is composed of about how many base pairs? a. anywhere from one to several dozen b. anywhere from several dozen to 100 c. anywhere from 100 to 1000 d. anywhere from several hundred to several million Answer: d Rationale: Human genes vary significantly in size, with some containing only a few hundred base pairs while others may contain several million. Option d encompasses this wide range, making it the most accurate choice for the size of a single human gene. 19. According to the text, the most significant thing that genes do is: a. determine how the brain will be constructed b. build proteins c. keep the organism alive by regulating physiological processes d. produce sperm and ova so organisms can reproduce Answer: b Rationale: The correct answer is b. build proteins. The primary function of genes is to provide instructions for synthesizing proteins, which are essential molecules involved in virtually all cellular processes. Proteins serve structural, enzymatic, regulatory, transport, and signaling roles within cells, contributing to the structure, function, and regulation of biological systems. 20. About how many different proteins have been identified in the human body? a. 200 b. 2,000 c. 20,000 d. 200,000 Answer: d Rationale: Over 200,000 different proteins have been identified in the human body. This diversity reflects the complexity of human biology and the various functions proteins serve in cellular processes. 21. Protecting the body from disease is the primary function of this type of protein: a. collagen b. antibody c. enzyme d. insulin Answer: b Rationale: Antibodies are proteins produced by the immune system in response to foreign substances (antigens) entering the body. Their primary function is to recognize and neutralize pathogens, thereby protecting the body from disease. Genes, Chromosomes, and Cell Division 22. How many PAIRS of chromosomes are in a normal human liver cell? a. 12 b. 23 c. 46 d. 92 Answer: b Rationale: In normal humans, all cells except sperm and eggs contain exactly 46 chromosomes arranged in 23 pairs. 23. The chromosomes of a cell, excluding those that determine sex, are called: a. gametes b. alleles c. autosomes d. enzymes Answer: c Rationale: The correct answer is c. autosomes. Autosomes are non-sex chromosomes that are present in pairs in diploid cells and contain genetic information unrelated to determining an individual's sex. In humans, autosomes comprise the first 22 pairs of chromosomes, with the 23rd pair consisting of the sex chromosomes (X and Y in males, XX in females). 24. Sarah states, “All normal human skin cells contain 46 genes.” To make Sarah’s statement correct, you would need to: a. change the word “genes” to “chromosomes” b. change the word “skin” to “blood” c. change the number “46” to “23” d. make all of the changes noted in the other three answer choices Answer: a Rationale: In normal humans, all cells except sperm and eggs contain exactly 46 chromosomes arranged in 23 pairs. 25. Julie and David are excited because Julie has undergone some prenatal testing and today they will see a picture of their unborn baby’s chromosomes. Such a picture is called: a. a genetic blueprint b. a karyotype c. a nucleotide d. an autosomal map Answer: b Rationale: A karyotype is a photograph of a cell’s chromosomes arranged in pairs according to size. 26. A photograph of a cell’s chromosomes arranged in pairs according to size is referred to as a: a. phenotype b. karyotype c. chromotype d. genotype Answer: b Rationale: The correct answer is b. karyotype. A karyotype is a visual representation of an individual's chromosomes arranged in pairs according to size, shape, and banding pattern. Karyotyping is commonly used in genetics and cytogenetics to assess chromosomal abnormalities, such as aneuploidy, translocations, and deletions, by examining the number, size, and structure of chromosomes in a cell's nucleus. 27. The two ways in which cells can divide are called: a. meiosis and mitosis b. autosomes and gametes c. gametes and polarization d. genotype and phenotype Answer: a Rationale: Cell division in organisms occurs primarily through two processes: meiosis and mitosis. Option a correctly identifies these two processes. 28. The type of cell division that occurs in autosomes is called: a. mutation b. codominant reproduction c. meiosis d. mitosis Answer: d Rationale: Mitosis is the type of cell division that occurs in autosomes. Autosomes are non-sex chromosomes, and mitosis is responsible for the replication and division of these somatic cells, ensuring each daughter cell receives an identical set of chromosomes. 29. Which chromosomal pair determines the sex of an individual? a. 19th b. 20th c. 22nd d. 23rd Answer: d Rationale: The 23rd chromosome pair is composed of sex chromosomes, which are labeled XX in females and XY in males. 30. If you were to examine a variety of human body cells under the microscope and look at the number of chromosomes contained in each, you would expect to see 46 chromosomes in all of the following cells EXCEPT: a. a sperm cell b. a liver cell c. a neuron d. a white blood cell Answer: a Rationale: In normal humans, all cells except sperm and eggs contain exactly 46 chromosomes arranged in 23 pairs. 31. Sperm and egg cells are called: a. autosomes b. genosomes c. gametes d. Golgi bodies Answer: c Rationale: Sperm and egg cells are known as gametes. These are specialized reproductive cells that carry half the number of chromosomes found in somatic cells, contributing to the genetic diversity of offspring during sexual reproduction. 32. Thomas (a man) knows that in his body, meiosis occurs in: a. only his brain b. only his white blood cells c. only his testes d. every cell in his body Answer: c Rationale: Meiosis is the process of cell division that yields sperm and ova, each including one half of a full set of chromosomes. In males, meiosis occurs in the texts. 33. Suppose that a human female is accidentally exposed to a poison at one of four different points in development. If the effect of the poison is that it interferes with meisosis, at which point in the lifespan would we expect it to have the most disruptive effect? a. in the prenatal period, since this is when ova are forming b. in the first year after birth, since this is when brain growth is most rapid c. during early adulthood, since this is when conception of a child is most likely to happen d. in older adulthood, since body cells are most vulnerable at the end of the lifespan Answer: a Rationale: Meiosis in females begins in the ovaries well before birth, where all of the roughly 400,000 ova a woman will ever have begin their development. The final cell division that produces the ovum does not occur until the female enters puberty. The most disruptive effect would be in the prenatal period, since interference at this stage would inhibit ova from even beginning to form. 34. In women, ova are formed: a. about one every day after reaching puberty b. about one or two a month, every month after reaching puberty c. about 100 every day after reaching puberty d. during the prenatal period Answer: d Rationale: Ova, or eggs, are formed during the prenatal period in females. Unlike sperm production, which occurs continuously throughout a male's life after puberty, ova are already present in the ovaries at birth and mature and are released cyclically, typically once a month, after reaching puberty. 35. Which of the following results from the process of meiosis? a. fertilized ovum b. alleles c. gametes d. proteins Answer: c Rationale: Meiosis is a specialized cell division process that results in the formation of gametes, which are sex cells such as sperm and eggs. During meiosis, the number of chromosomes is halved, leading to the production of haploid gametes that contain only one set of chromosomes. Therefore, option c, gametes, is the correct answer. 36. Another term used to refer to either ova or sperm is: a. alleles b. gametes c. phenotypes d. proteins Answer: b Rationale: Gametes are reproductive cells, either ova (eggs) or sperm, that unite during sexual reproduction to form a new organism. They are specialized cells containing half the normal number of chromosomes, ensuring that when they combine during fertilization, the resulting zygote has the correct chromosome number. Therefore, option b, gametes, is the correct term used to refer to ova or sperm. 37. The cell division process that results in the formation of gametes is called: a. meiosis b. gene imprinting c. transcription d. mitosis Answer: a Rationale: Meiosis is the specific type of cell division that occurs in sexually reproducing organisms to produce gametes, such as sperm and egg cells. During meiosis, the chromosome number is halved, resulting in haploid cells with half the number of chromosomes as the parent cell. This reduction in chromosome number is essential for maintaining the correct chromosome number in the species after fertilization occurs. Therefore, option a, meiosis, is the correct answer. 38. The term used to describe alternate versions of the same gene is: a. alleles b. chromosomes c. autosomes d. gametes Answer: a Rationale: Alleles are alternate versions of the same gene. They can differ in sequence and lead to variations in traits among individuals. 39. The term that refers to an individual’s genetic make-up is __________; the term that refers to the physical characteristics that result from that genetic make-up is __________: a. autosomes; gametes b. gametes; autosomes c. phenotype; genotype d. genotype; phenotype Answer: d Rationale: Genotype refers to the genetic constitution of an individual, including the combination of alleles present in their DNA. It represents the specific genes an individual possesses. On the other hand, phenotype refers to the observable physical or biochemical characteristics of an organism, which result from the interaction between the genotype and the environment. Therefore, option d, genotype; phenotype, correctly defines the terms. 40. Suppose that the gene that determines how many fingers a person has is coded such that having 5 fingers is dominant and having 6 fingers is recessive. If a person’s mother has 5 fingers and his father has 6 fingers, what is the probability that he will be born with 6 fingers? a. 0 % b. 50 % c. 100 % d. the percent cannot be determined because we do not know if his mother is homozygous or heterozygous for this trait Answer: d Rationale: Normally, recessive traits are only expressed when a person has inherited two recessive genes. In this example, if the person’s mother is heterozygous for the trait, then the person would have a 50% chance of being born with 6 fingers. In this case, the father would contribute the recessive gene and there would be a 50% chance that the mother would contribute the recessive gene. As a result, there would be an overall 50% chance that the person would inherit both recessive genes and be born with 6 fingers. However, if the mother is homozygous for the trait, she will contribute the dominant gene which, even when combined with the recessive gene from the father, would never result in the presentation of the recessive trait of having 6 fingers. Thus, determining a precise probability would require that we know whether the mother is heterozygous or homozygous for the trait. 41. If the gene for blue eyes is recessive, and if John’s mother and father both have blue eyes, we know that John: a. will be homozygous on the eye color trait b. will be heterozygous on the eye color trait c. will have a 50% chance of having blue eyes d. will have a 25% chance of having blue eyes Answer: a Rationale: Normally, recessive traits are only expressed when a person has inherited two recessive genes. In this example, one should assume that both the mother and father, having blue eyes, have two recessive genes. It follows that each would have had to contribute a recessive gene, resulting in John being homozygous on the eye color trait. 42. Suppose that Shelly’s mother has brown eyes and her father has blue eyes. Shelly has brown eyes. In this example we would ______ Shelly’s phenotype for eye color and would _________ Shelly’s genotype for eye color. a. know; not know b. not know; know c. know; know d. not know; not know Answer: c Rationale: In genetics, the phenotype refers to those traits that are expressed in the individual. Thus, we know the phenotype: Shelly has brown eyes. The genotype refers to the genetic code of a given individual. Because the gene for brown eyes is dominant, Shelly would have brown eyes whether she inherited a recessive gene from her father and a dominant gene from her mother or whether she inherited dominant genes from both parents. Thus, we cannot determine Shelly’s genotype from the information provided. 43. Suppose that hair color is a single-gene trait and that dark hair is dominant and blonde hair is recessive. Also, suppose that Terry’s mother has dark hair and his father has blonde hair. If Terry has blonde hair, we would ______ Terry’s phenotype for hair color and would ________ Terry’s genotype for hair color. a. know; not know b. not know; know c. know; know d. not know; not know Answer: c Rationale: In genetics, the phenotype refers to those traits that are expressed in the individual. Thus, we know the phenotype: Terry has blonde hair. The genotype refers to the genetic code of a given individual. Because blonde hair is recessive, we can determine Terry’s genotype: he would have to have inherited recessive genes from both his parents. 44. Suppose that eye color is a single gene trait and that brown eyes is a dominant allele and blue eyes is a recessive allele. If Mark has brown eyes, we would know: a. that Mark is heterozygous for the eye color trait b. that Mark is homozygous for the eye color trait c. Mark’s genotype d. Mark’s phenotype Answer: d Rationale: In genetics, the phenotype refers to those traits that are expressed in the individual. Thus, we know the phenotype: Mark has brown eyes. 45. Assume that eye color is a single gene trait and that brown eyes is a dominant allele and blue eyes is a recessive allele. If Harry’s mother and father both have brown eyes and are both heterozygous on this trait, what is the probably that he will have brown eyes, too? a. 100% b. 75% c. 50% c. 25% Answer: b Rationale: Heterozygous refers to the arrangement in which the two alleles for a simple dominant–recessive trait differ. One possibility is that Harry could inherit a recessive allele from his father and a recessive allele from his mother, which would result in blue eyes. Alternatively, he could inherit a recessive allele from his father and a dominant allele from his mother, a dominant allele from his father and a recessive allele from his mother, or dominant alleles from both parents – all circumstances that would result in Harry having brown eyes. 46. A mother and a father have four children (biological not adopted). All four children have blue eyes. Assuming that brown eyes is a dominant trait and blue eyes is a recessive trait, which of the following statements must be true? a. The parents may have brown or blue eyes, but both must have at least one allele for blue eyes. b. The parents may have brown or blue eyes, but both must have at least one allele for brown eyes. c. At least one of the parents must have blue eyes. d. Both of the parents must have blue eyes. Answer: a Rationale: For a recessive trait to be expressed, a child must inherit two recessive alleles. Thus, for a child to have blue eyes, both parents must have at least one recessive allele (i.e., allele for blue eyes). 47. The term “polygenic inheritance” refers to which of the following? a. a trait that is determined by a single gene pair b. the idea that half of our genes come from each of our parents c. a trait that is present in the individual’s phenotype d. a trait caused by an interaction of several genes or gene pairs Answer: d Rationale: In polygenic inheritance, the inheritance of a trait is determined by multiple genes. 48. Dr. Ramley states that intelligence is determined by the action of hundreds of different genes. She has just defined intelligence as a _________ trait. a. dominant b. recessive c. polygenic d. heterozygous Answer: c Rationale: Polygenic inheritance is defined as the inheritance of a trait that is determined by multiple genes. 49. Color blindness is a sex-linked trait. As such, if a child is color blind, we can be assured that the child’s genotype includes: a. a recessive gene on the X chromosome inherited from his mother b. a dominant gene on the X chromosome inherited from his mother c. a recessive gene on the Y chromosome inherited from his father d. a dominant gene on the X chromosome inherited from his father Answer: a Rationale: Sex-linked traits are those that are determined by genes on the 23rd chromosome pair. If a normally recessive allele appears on the male’s X chromosome, there often is no allele on the Y chromosome to offset it, and the recessive trait will be expressed as the individual’s phenotype. In contrast, in females, the recessive trait will be expressed only if it occurs on both X chromosomes. Regardless of whether the child is male or female, the mother must contribute a recessive gene on the X chromosome in order for the trait to be expressed. 50. Sickle-cell anemia is a genetic disorder that is best considered an example of: a. dominance b. incomplete dominance c. recessive alleles d. codominance Answer: b Rationale: Sickle-cell anemia is an example of incomplete dominance. In this condition, a person with two copies of the sickle-cell allele has the disease, while a person with one copy may exhibit some symptoms but generally has milder effects. 51. The AB blood type is an example of a condition that results from: a. dominance b. incomplete dominance c. recessive alleles d. codominance Answer: d Rationale: The AB blood type results from codominance, where both alleles for blood type A and B are expressed equally in an individual's phenotype. This leads to the expression of both A and B antigens on the surface of red blood cells in individuals with the AB blood type. 52. Suppose that a disease is inherited. Your mother has the disease, your father does not, and you have a very minor case of the disease which lies somewhere in between your mother’s and father’s situation. In this case, we would know that the alleles that determine this trait: a. are recessive b. are dominant c. are codominant d. are heterozygous Answer: c Rationale: Codominance refers to a situation in which neither allele is dominant over the other. When codominant traits are inherited, the result is a phenotype that is a blend. 53. An example of a trait that results from incomplete dominance is ________; a trait that results from codominant alleles is __________: a. sickle-cell anemia; blood type b. leukemia; breast cancer c. heart disease; liver cancer d. multiple sclerosis; Lou Gehrig’s disease Answer: a Rationale: Sickle-cell anemia is an example of incomplete dominance, where the heterozygous condition (having one normal allele and one sickle-cell allele) results in an intermediate phenotype. Blood type, such as ABO blood group system, is an example of codominant alleles, where both alleles are expressed fully in the phenotype. 54. The blood clotting disease, hemophilia, occurs much more frequently in males because it is caused by a recessive gene carried on the sex chromosomes. As such, it would be referred to as: a. a heterozygous trait b. a homozygous trait c. a sex-linked trait d. a codominant trait Answer: c Rationale: Sex-linked traits are, by definition, those that are determined by genes on the 23rd chromosome pair (the sex chromosomes). Sex-linked traits are not, by definition, heterozygous or homozygous. If a normally recessive allele appears on the male’s X chromosome, there often is no allele on the Y chromosome to offset it, and the recessive trait will be expressed as the individual’s phenotype. In contrast, in females, the recessive trait will be expressed only if it occurs on both X chromosomes. 55. Sometimes in meiosis, genetic material from the mother and father is exchanged between chromosomes. This process is called and the alleles that carry the combination of both parents’ genes are called alleles. a. phenotypic inheritance; phenotypic b. polygenetic inheritance; independent c. incomplete dominance; codominant d. crossing over; recombinant Answer: d Rationale: The process described is called crossing over, where genetic material from homologous chromosomes is exchanged during prophase I of meiosis. The resulting chromosomes contain a combination of alleles from both parents and are called recombinant alleles. 56. The last stage of meiotic division, in which chance determines which half of each chromosome pair will go into which sperm or ovum, involves the process called: a. mitosis b. independent assortment c. recombination d. codominant configuration Answer: b Rationale: Independent assortment occurs during the metaphase I stage of meiosis, where homologous chromosomes line up randomly at the metaphase plate. This process leads to the random distribution of maternal and paternal chromosomes into gametes, contributing to genetic diversity in offspring. 57. Mr. Martin is worried that, if he has a child, the child might be “unlucky” and get the “bad half” of his chromosome pairs. Mr. Martin’s worry would technically be referred to as an issue involving: a. recombinant alleles b. independent assortment c. codominance in allele pairs c. mutation Answer: b Rationale: Independent assortment refers to the final stage of meiotic division, in which chance determines which half of the chromosome pairs will go into which sperm or ovum. 58. If all cells in a person’s body have a particular mutation present, we can conclude that the mutation most likely occurred: a. during mitosis b. during meiosis c. shortly after birth d. sometime after puberty Answer: b Rationale: At the molecular level, a mutation is an alteration in the DNA that typically occurs during mitosis or meiosis. A small number of mutations are viable—the mutated cell survives. In mitotic cell division, if a viable mutation occurs early in development, it will then be passed along to all the cells replicated in subsequent divisions of that cell. When mutation occurs during meiosis, on the other hand, it is incorporated into the genetic code passed along to offspring in the sperm or ova. Genetic and Chromosomal Disorders 59. According to the text, genetic mutations are: a. extremely rare, occurring only in about 0.1% of the population. b. found only in individuals who are over the age of 4 since do not begin to occur until some development has taken place. c. always negative, in that they always make it more difficult for the individual to survive. d. quite common. Answer: d Rationale: Genetic mutations are quite common and can occur spontaneously or be induced by various factors such as environmental exposures. They can have varying effects on individuals, ranging from neutral to beneficial or harmful. 60. Dr. Gage argues that hereditary and environmental forces can never be understood separately, since they are continually influencing each other. This statement is best considered to reflect the concept of: a. independent assortment b. gene-environment interactions c. recombinant processes d. polygenetic inheritance Answer: b Rationale: The central concept of gene-environment interactions is that genetic and environmental forces are in constant interaction with each other: genes influence the environments we select and environmental events can influence how genes are expressed. 61. About what percent of the DNA molecule is made up of protein-coding genes: a. about 2% b. about 25% c. about 60% d. nearly 100% Answer: a Rationale: Only about 2% of the human genome consists of protein-coding genes. The remaining portion includes non-coding DNA regions involved in regulatory functions, structural elements, and repetitive sequences. 62. The part of the DNA molecule that does not function as genes, but that can influence how genes work is referred to as a. polygenetic forces b. recombinant processes c. epigenetic forces d. meta-genetic forces Answer: c Rationale: Epigenetic forces refer to modifications to the DNA molecule that do not involve changes to the underlying DNA sequence but can influence gene expression. These modifications include DNA methylation, histone modifications, and non-coding RNA molecules. Epigenetic changes can affect how genes are turned on or off, thereby influencing various cellular processes and phenotypic outcomes. 63. Andre explains that early malnutrition – an environmental condition – actually may change the way that genes express themselves. In other words, starvation turns some genes “off” and others “on,” thereby influencing genetic processes. The central argument that Andre is making emphasizes the basic idea of: a. epigenetics b. polygenic inheritance c. incomplete dominance d. recombinant processes Answer: a Rationale: Epigenetics refers to the idea that nongenetic factors can change the way that genes are expressed. Here, malnutrition is an environmental condition that influences these epigenetic processes, which in turn influence how genes behave. 64. What percent of babies born today in the United States are healthy and normal? a. 60% b. 73% c. 87% d. 97% Answer: d Rationale: According to the provided information, 97% of babies born today in the United States are healthy and normal. This statistic reflects the overall health status of newborns in the country. 65. Anne mentions that her cousin has a congenital anomaly. You would know that this is sometimes also referred to as: a. a sex-linked trait b. a birth defect c. an autosomal disorder d. a heterozygous trait Answer: b Rationale: Congenital anomalies are abnormalities that result from genetic and chromosomal problems as well as from exposure to toxins, disease, and such during the prenatal period. These anomalies are still often referred to as birth defects. 66. Which of the following is NOT a sex-linked disorder? a. Down syndrome b. hemophilia c. Fragile X syndrome d. color blindness Answer: a Rationale: Down syndrome is not a sex-linked disorder. It is caused by the presence of an extra chromosome 21 and is typically not associated with the sex chromosomes. 67. Which of the following sex-linked disorders occurs most frequently? a. Klinefelter’s syndrome b. Turner’s syndrome c. hemophilia d. color blindness Answer: d Rationale: Color blindness is the most common sex-linked disorder, particularly affecting males more frequently than females. It is caused by mutations in genes located on the X chromosome, making it an X-linked disorder. Since males have only one X chromosome (XY), they are more likely to express the trait if they inherit the recessive allele for color blindness from their mother. Females would need to inherit two recessive alleles (one from each parent) to express the trait, making them less likely to be affected. 68. Which of the following inherited disorders results in problems with blood clotting? a. Klinefelter’s syndrome b. Turner’s syndrome c. hemophilia d. color blindness Answer: c Rationale: Hemophilia is an inherited disorder that results in problems with blood clotting. It is caused by mutations in genes that encode clotting factors. 69. Which of the following syndromes occurs only in females? a. Down syndrome b. Turner’s syndrome c. Klinefelter's syndrome d. Fragile X syndrome Answer: b Rationale: Both Down syndrome and Fragile X occur in both males and females. Klinefelter’s syndrome appears in only males. Turner’s syndrome appears in only females and occurs when one of the X chromosomes is missing or inactive. 70. Todd is mentally retarded, sterile, and has small external genitalia, undescended testicles, and breast enlargement. His chromosome pattern is XXY. Since puberty, he has received hormone replacement therapy in order to maintain his secondary-sex characteristics. What sex-linked abnormality does Todd most likely have? a. Klinefelter’s syndrome b. Down syndrome c. Turner's syndrome d. Fragile X syndrome Answer: a Rationale: Klinefelter’s syndrome occurs in about 1 of 1,000 males and involves the characteristics described: sterility, small external genitalia, undescended testicles, and breast enlargement. 71. Olaf has been diagnosed with Klinefelter's syndrome. What is his chromosomal pattern? a. XO b. XY c. XXY d. XYY Answer: c Rationale: Klinefelter’s syndrome can result from any of the following chromosomal patterns: XXY,XXXY,XXXXY 72. Which of the following conditions is a sex-linked abnormality that can occur in both males and females? a. Fragile X syndrome b. Klinefelter’s syndrome c. Turner's syndrome d. Down syndrome Answer: a Rationale: Klinefelter’s syndrome occurs only in males and Turner’s syndrome occurs only in females. Down syndrome can occur in both males and females, but results from a variation on the 21st chromosome pair rather than on the 23rd chromosome pair (i.e., sex chromosomes). 73. Individuals with this syndrome have a functional X chromosome, but either a missing or inactive second X chromosome. a. Klinefelter’s syndrome b. Fragile X syndrome c. Down syndrome d. Turner’s syndrome Answer: d Rationale: Turner’s syndrome is characterized by the presence of a functional X chromosome and a missing or inactive second X chromosome. This condition typically affects females and can lead to various physical and developmental abnormalities. 74. Melissa has a single X chromosome and no Y chromosome, an immature female appearance, and lacks internal reproductive organs. What is the most appropriate diagnosis of her condition? a. Down syndrome b. Turner's syndrome c. Fragile X syndrome d. Klinefelter’s syndrome Answer: b Rationale: Turner syndrome occurs in about 1 of 10,000 females. One of the X chromosomes is either missing or inactive. The characteristics of Turner syndrome match Melissa’s: Individuals with Turner syndrome usually have an immature female appearance—they do not develop secondary sex characteristics. They also lack internal reproductive organs. These females may be abnormally short, and some are mentally retarded. The disorder is usually discovered at puberty, and hormone replacement therapy can help with a more normal appearance. 75. Andre is a hemophiliac, which means that he has problems with: a. blood clotting b. exocrine glands c. amino acid metabolism d. muscle control Answer: a Rationale: Hemophilia A and B are disorders that interfere with normal blood clotting and occur at different loci on the X chromosome. Hemophilia A is usually accompanied by color blindness. 76. If Margaret (a woman) is becoming bald as the result of a genetic trait called pattern baldness, we would know that she inherited a _______ allele for this trait from her mother and a ___________ allele from her father: a. dominant; recessive b. recessive; dominant c. dominant; dominant d. recessive; recessive Answer: d Rationale: Pattern baldness, which can include a receding hairline, loss of hair on the top of the head, or overall hair thinning, is a common example of a sex-linked disorder. Many men inherit the recessive allele and some display pattern baldness as early as in their teens. Many women carry the recessive allele as well, but a dominant allele on the other X chromosome prevents pattern baldness from being displayed. Unless a woman inherits a recessive allele from both parents, she is unlikely to display this genetic trait. 77. The primary reason that sex-linked traits are observed more frequently in men than in women is that: a. mutations are much more common in male offspring b. male babies are weaker so are more likely to be spontaneously aborted if any developmental process is compromised c. the Y chromosome is much smaller and has fewer genes than the X chromosome d. women generally do not talk about sex-related behavior as much as do men Answer: c Rationale: Sex-linked traits are, by definition, those that are determined by genes on the 23rd chromosome pair (the sex chromosomes). If a normally recessive allele appears on the male’s X chromosome, there often is no allele on the Y chromosome to offset it, and the recessive trait will be expressed as the individual’s phenotype. In contrast, in females, the recessive trait will be expressed only if it occurs on both X chromosomes. Because a trait will be expressed in males when two recessive alleles are inherited or when a recessive allele is inherited from the mother and no allele appears on the Y chromosome to offset it, sex-linked traits are more frequently observed in men than in women. 78. If we know that a disease results from a sex-linked recessive trait, we would expect that it would: a. be more common among men than women b. be more common among women than men c. develop earlier in life for boys than girls d. develop earlier in life for girls than boys Answer: a Rationale: Traits that are controlled by the sex chromosomes (X and Y) are called sex-linked traits. Because the males’ Y chromosome is smaller than the females’ second X, men are more likely to display recessive sex-linked traits in their phenotype. 79. Having an African-American ancestry puts individuals at higher risk for developing which of the following genetic disorders? a. sickle-cell trait and sickle-cell anemia b. cystic fibrosis c. Tay-Sachs disease d. Down syndrome Answer: a Rationale: Sickle-cell trait occurs in about 1 of 12 U.S. African Americans; sickle-cell anemia occurs in about 1 of 500. Other groups whose ancestors lived in low-lying malarial wetlands show high rates as well. 80. Which recessive genetic disorder occurs primarily among people of European Ashkenazi Jewish ancestry, resulting in early death in those children afflicted with it? a. cystic fibrosis b. Tay-Sachs disease c. phenylketonuria d. sickle-cell anemia Answer: b Rationale: Independent assortment occurs during the metaphase I stage of meiosis, where homologous chromosomes line up randomly at the metaphase plate. This process leads to the random distribution of maternal and paternal chromosomes into gametes, contributing to genetic diversity in offspring. 81. At birth, Debbie was given a mandatory screening test and tested positive for a disorder that required her to be placed immediately on a restricted diet to control her symptoms. Which of the following is mostly likely the condition for which she is being treated? a. sickle-cell anemia b. Huntington’s disease c. cystic fibrosis d. phenylketonuria Answer: d Rationale: Phenylketonuria (PKU) is a metabolic disorder that requires a restricted diet to control symptoms. Infants with PKU lack the enzyme needed to process phenylalanine, an amino acid found in many foods. 82. Which of the following disorders occurs only when the gene involved is inherited from the mother and not the father? a. Prader-Willi syndrome b. Angelman syndrome c. Fragile X syndrome d. Down syndrome Answer: a Rationale: Prader-Willi syndrome is caused by the loss of function of specific genes on the paternal chromosome 15. This syndrome occurs when the paternal copy of chromosome 15 is missing or unexpressed, while the maternal copy is active. Since Prader-Willi syndrome results from the absence of paternal genetic material, it only occurs when the gene involved is inherited from the mother and not the father. 83. If a child has mutated genes on chromosome 15 contributed by the mother, he or she will be at risk for developing _______; if the mutated genes are from the father, he or she will be at risk for developing _______. a. Angelman syndrome; Prader-Willi syndrome b. Prader-Willi syndrome; Angelman syndrome c. Turner’s syndrome; Klinefelter’s syndrome d. Klinefelter’s syndrome; Turner’s syndrome Answer: b Rationale: Mutated genes on chromosome 15 contributed by the mother can lead to Angelman syndrome, while mutated genes from the father can lead to Prader-Willi syndrome. 84. Rene has Down syndrome, which means that she has an extra chromosome on which chromosome pair? a. the 7th pair b. the 18th pair c. the 21st pair d. the 23rd pair Answer: c Rationale: As noted in the textbook, the most frequent type of Down syndrome is trisomy-21, in which an extra chromosome is attached to the 21st pair. 85. Which of the following genetic disorders is the result from a problem associated with the autosomes? a. Fragile X syndrome b. Turner's syndrome c. Klinefelter’s syndrome d. Down syndrome Answer: d Rationale: Fragile X syndrome, Turner’s syndrome, and Klinefelter’s syndrome are all sex-linked disorders. Down syndrome is not a sex-linked disorder, rather it involves an extra chromosome being attached to the 21st pair. 86. Down syndrome has been shown to be related to which of the following? a. father’s age b. mother’s age c. parents’ ethnic background d. mother’s diet during pregnancy Answer: b Rationale: As noted in the textbook, Down syndrome occurs about once in every 1,000 live births for mothers under age 35, and the incidence steadily increases as the age of the mother increases. 87. George’s younger brother is diagnosed at birth with “trisomy-21.” Another term for this condition is: a. Klinefelter’s syndrome b. Supermale syndrome c. Fragile X syndrome d. Down syndrome Answer: d Rationale: As noted in the textbook, The most frequent type of Down syndrome is trisomy-21, in which an extra chromosome is attached to the 21st pair. 88. Suppose researchers identify a genetic disorder that has negative consequences if the gene is inherited from the mother, but no consequences at all if it is inherited from the father. According to the text, this situation would be: a. impossible b. an example of gene imprinting c. an example of a sex-linked trait d. an example of an autosomal disorder Answer: b Rationale: Gene imprinting refers to a phenomenon in which gene expression and phenotype depend on which parent the genes come from. 89. Although most of an individual’s DNA is contained in the cell nucleus, some is also contained in the: a. ribosomes b. mitochondria c. endoplasmic reticulum d. cell membrane Answer: b Rationale: DNA is also contained in mitochondria, where it plays a crucial role in mitochondrial function and energy production. 90. What percent of mitochondrial DNA is inherited from the mother: a. it varies from individual to individual b. 100% of the child is female; 50% is the child is male c. 100% if the child is male; 50% if the child is female d. 100% for both male and female children Answer: d Rationale: Mitochondrial DNA (mtDNA) is inherited exclusively from the mother in humans. During fertilization, the mitochondria in the sperm are typically destroyed, while those in the egg are retained, leading to the inheritance of mtDNA only from the mother. Therefore, regardless of whether the child is male or female, they inherit 100% of their mitochondrial DNA from their mother. 91. According to the text, most individuals harbor about ______ potentially lethal recessive genes: a. none or 1 b. 5 to 8 c. 50 to 75 d. hundreds Answer: b Rationale: Most individuals carry about 5 to 8 potentially lethal recessive genes, which may not manifest unless inherited from both parents. 92. In his professional career, Andy wants to study the risk factors associated with genetic disorders and to provide information and support to parents whose risk factors are high. Andy wants to enter the field called: a. genetic counseling b. pediatric social work c. prenatology d. bioethical statistics Answer: a Rationale: Genetic counseling refers to a widely available resource that can help potential parents evaluate genetic risk factors in childbearing and enable them to make choices that reflect their values and circumstances. 93. Which of the following types of information would be of LEAST interest to a genetic counselor? a. parents’ ages b. parents’ illnesses c. parents’ ethnic background d. parents’ income Answer: d Rationale: Genetic counseling often includes the analysis of parental medical records and family histories to construct a genetic “pedigree,” which identifies previous instances where congenital anomalies have occurred. Other techniques, such as parental blood analysis or prenatal screening, can detect many chromosomal or genetic anomalies. Parents’ income does not provide information in helping the counselor construct a person’s genetic “pedigree.” 94. Workers in Dr. Garcia’s lab first obtain tumor cells from patients with cancer. They then remove the DNA from the tumor cell nuclei and use enzymes to segment the DNA strands into sections. Finally, they insert the DNA sections in which they are interested into “host” bacteria cells, where the DNA can be reproduced for later use. Dr. Garcia’s lab is engaged in work involving: a. behavior genetics b. recombinant technology c. cryogenics d. autosomal transmission Answer: b Rationale: As defined in the textbook, recombinant DNA technology refers to an assortment of highly sophisticated procedures in which DNA is extracted from cell nuclei and cut into segments; the resulting fragments are then joined to self-replicating elements, in essence forming functional gene clones. These are then placed in host bacterial cells to be maintained and cultured. 95. Which of the following is the best summary of the current state of gene therapies, such as the use of retroviruses? a. The theoretical work about how such processes might work is still incomplete. b. Gene therapies have been developed but ethical concerns have prevented their use in humans at the present time. c. Gene therapies have been developed and tried, but with limited success so far. d. Gene therapies are used routinely with very good success in treating a number of genetic diseases. Answer: c Rationale: As noted in the textbook, a gene therapy approach that involves reinserting genetically altered cells into the person from whom they were harvested has been tried with various genetic disorders but with limited success thus far. Additionally, the retrovirus approach also has experienced only limited success; however, it holds great promise for the future if certain technical obstacles can be overcome. 96. Viruses used in gene therapy that are capable of penetrating cells and inserting modified DNA into them are called: a. recombinant viruses b. re-engineered viruses c. retroviruses d. macroviruses Answer: c Rationale: Retroviruses are a type of virus commonly used in gene therapy because of their ability to integrate their genetic material into the host cell's genome. This integration allows the modified DNA carried by the retrovirus to be permanently incorporated into the host cell's DNA. Retroviruses achieve this through the action of the enzyme reverse transcriptase, which converts the viral RNA genome into DNA before integration into the host genome. Behavior Genetics 97. The field of behavior genetics relies most heavily on data gathered from: a. chromosomes b. diseased tissue c. psychological tests and interviews d. viruses Answer: c Rationale: The field of behavior genetics relies most heavily on data gathered from psychological tests and interviews to study the genetic and environmental influences on behavior and mental processes. 98. If it were possible to know exactly what genetic information was contained in an individual’s genes, would the field of behavioral genetics have any usefulness? a. No b. Yes, because some genes are recessive c. Yes, because some traits are polygenic d. Yes, because the way traits are expressed is often dependent on the environment Answer: d Rationale: Even if we had complete knowledge of an individual’s genome, this would provide only a partial explanation for how that person’s traits would be expressed within an interactive environmental context. Understanding how genetic characteristics operate within particular environmental settings is the focus of behavior genetics. 99. The extent to which biologically related people show similar characteristics is measured by a technique called: a. genetic engineering b. recombinant technology c. concordance d. behavioral genetics Answer: c Rationale: Concordance is a statistical measure used in genetics to assess the degree of similarity or agreement between traits or conditions in individuals who are biologically related, such as twins or family members. It indicates the likelihood that if one individual has a particular trait or condition, their relative will also have it. Concordance studies are commonly used in fields like behavioral genetics to investigate the role of genetic and environmental factors in the expression of traits or diseases within families. 100. Dr. Smith studies a group of 1,000 people who have schizophrenia and who also have identical twins. He finds that 47% of the identical twins also develop this disease. The type of statistical information Dr. Smith’s study reveals is called: a. concordance b. an H-E (Heredity-Environment) Index c. a genetic-based percentage d. analysis of variance Answer: a Rationale: The primary tool of behavior genetics is the statistical technique of correlation, which measures concordance: the extent to which biologically related people show similar characteristics. 101. Doug believes that a person’s intelligence is about half inherited and half dependent on how the person grows up. Doug’s statement best reflects a concept that researchers would call: a. codominance b. a genetic predisposition c. heritability d. a heterozygous trait Answer: c Rationale: Heritability is the proportion of a trait, such as intelligence, that is thought to result from inherited, genetic factors. 102. The extent to which a trait is inherited versus acquired through interactions with the environment defines the concept of: a. heritability b. genetic predisposition c. genetic engineering d. concordance Answer: a Rationale: Heritability refers to the proportion of the variability in a trait within a population that is attributable to genetic factors. It assesses the degree to which individual differences in a trait can be attributed to genetic variation rather than environmental factors. 103. If a particular trait is highly heritable, we would expect to see the highest concordance rates among: a. identical twins b. fraternal twins c. parents and children d. unrelated individuals of the same age Answer: a Rationale: Heritability refers to the extent to which a trait is inherited versus acquired, thus presuming a genetic basis. In this example, the trait is highly heritable, so we presume a strong genetic basis. Because identical twins are genetically identical (share 100% of their genetic makeup) we would expect them to show the most similar characteristics. 104. If the heritability of a trait was .50, we would expect to see the highest concordance rates among: a. identical twins raised together in the same home b. identical twins raised in different homes c. fraternal twins raised in different homes d. unrelated individuals Answer: a Rationale: Concordance refers to the extent to which biologically related people show similar characteristics. A heritability of .50 suggests that genetics and environment contribute relatively equally to the expression of the trait. Thus, the individuals who share both the highest genetic makeup and share an environment would be expected to show the most similar characteristics. 105. If the heritability of a trait is greater than 0 but less than 100%, this would mean that: a. heredity was a larger influence on the trait than environment b. environment was a larger influence on the trait than heredity c. both heredity and environment influence the trait d. heredity and environment do not interact in their influence on this trait Answer: c Rationale: Heritability refers to the proportion of a trait, such as intelligence, that is thought to result from inherited, genetic factors. A proportion less than 100% but more than zero would indicate that there is some genetic basis to the trait, the remainder of which is explained by environmental factors. 106. Which of the following results is consistent with a trait that has a high heritability? a. identical twins are less alike than fraternal twins b. adopted children resemble their biological parents more than their adoptive parents c. unrelated children are as much alike as are brothers and sisters d. brothers are more alike than are sisters Answer: b Rationale: Heritability refers to the proportion of a trait, such as intelligence, that is thought to result from inherited, genetic factors. If a trait is highly heritable, we would expect persons who are more genetically similar to one another to show more similarity on a trait than persons who are less genetically similar to one another. In this example, adopted children share more genes with their biological parents than with their adoptive parents, so should resemble the biological parents more. 107. Based on the heritability studies cited in the text, the appropriate conclusion to draw is that: a. genes are important in physical development, but not in cognitive and personality development b. genes are important in physical and cognitive development but not in personality development c. genes play only a minor role in human development, regardless of the domain in question d. genes play a significant role in human development of a wide range of human traits and behaviors Answer: d Rationale: Overall the research presented in the book indicates that genes play a significant role across a variety of traits and behaviors. For example, the book mentions a recent meta-analytic study of over 400 individual studies of the heritability of traits—including intelligence, language ability, psychiatric disorders including anxiety and depression, personality traits, and antisocial problems—that suggests that 41% of human behavior is genetically influenced (Malouff, Rooke, & Schutte, 2008). 108. According to research presented in the text, you should conclude that, under normal circumstances, about what percent of a person’s intelligence is the result of environmental, rather than genetic, factors? a. nearly 100% b. about half c. a small but measurable percent d. virtually zero percent Answer: b Rationale: According to the text, looking across a variety of studies, a consistent estimate is that genetics contributes about 50% to intelligence. 109. Research suggests that a portion of intelligence is inherited. What percentage of an individual’s intelligence is generally believed to be due to inherited factors? a. 10% or less b. around 50% c. around 75% d. over 90% Answer: b Rationale: Studies in behavioral genetics, including twin studies and adoption studies, suggest that genetic factors contribute significantly to individual differences in intelligence. While the exact percentage varies across studies and populations, it is generally believed that around 50% of an individual's intelligence is due to inherited factors. This estimate implies that environmental factors also play a substantial role in shaping intelligence. 110. According to research presented in the text, you should conclude that, under normal circumstances, about what percent of a person’s personality is the result of genetic factors? a. nearly 100% b. about a third to a half c. about 2 to 5% d. virtually zero percent Answer: b Rationale: Studies estimate a genetic contribution to personality of about 40% (Bouchard, 1999), perhaps ranging from 20 to 50% depending on the situation (Rushton, Bons, & Hur, 2008; Segal, 2000). Environmental Influences and Contexts 111. The technique that allows researchers to consider the results of several similar studies while weighing the quality of each is called: a. analysis of variance b. meta-analysis c. epigenetic analysis d. multiple regression analysis Answer: b Rationale: Meta-analysis is a technique used in research that involves synthesizing the results of multiple studies on a particular topic to provide a more comprehensive and reliable understanding of the phenomenon under investigation. 112. While sitting in a quiet waiting room, Ronnie at first is quite distracted by the clicking sound made by an old clock ticking away the seconds. However, after a few minutes, he no longer notices the ticking. This example best highlights the concept involved in: a. concordance b. classical conditioning c. habituation c. social learning Answer: c Rationale: In habituation, a person ceases to attend or respond to repetitive stimulation. 113. A researcher records the number of “sucks” a baby takes on her pacifier as she is shown pictures of adult faces. The researcher notes that when her mother’s face is shown, the baby stops sucking entirely. This experimental method relies most directly on an understanding of which of the following learning processes? a. habituation b. operant conditioning c. reinforcement d. self-efficacy Answer: a Rationale: In habituation, a person ceases to attend or respond to repetitive stimulation. In this case, the researcher knows that the baby demonstrates habituation to the mother’s face because the face is familiar (in other words, it is an example of repetitive stimulation). 114. While taking a test, suppose you are distracted by the student next to you who is smacking her gum as she chews it. However, after a few minutes, you no longer attend to the smacking, even though your neighbor keeps doing this. Your response in this situation is best considered to be the result of: a. reinforcement b. punishment c. classical conditioning d. habituation Answer: d Rationale: In habituation, a person ceases to attend or respond to repetitive stimulation. 115. When a person repeatedly experiences the same stimulus, he or she typically will tend to respond to it less and less with each repetition. This process is referred to as: a. classical conditioning b. punishment c. operant conditioning d. habituation Answer: d Rationale: In habituation, a person ceases to attend or respond to repetitive stimulation. 116. The key to understanding how classical conditioning works is to recognize that it involves the _________ of what will come. a. reinforcement b. punishment c. prediction d. repression Answer: c Rationale: In classical conditioning, learning occurs when, through repeated trials, we learn to associate one stimulus with another naturally occurring stimulus–response sequence. In other words, we learn that a stimulus predict that a sequence of events will occur. 117. Three-year-old Kayla has been seeing her pediatrician for checkups every six months and fears the shots she receives each time. Now, even though he does not administer the shots, Kayla cries when the pediatrician enters the room because she associates him with receiving shots. The pediatrician has become a(n): a. conditioned stimulus b. conditioned response c. unconditioned stimulus d. unconditioned response Answer: a Rationale: In classical conditioning, a naturally occurring reflex becomes associated with an environmental cue. In this case, the fear that accompanies an impending shot has become associated with the pediatrician who has administered these shots in the past. The pediatrician is the environmental cue. 118. An unreasonable fear of an object or a situation is referred to as a: a. phobia b. conditioning c. habituation d. reinforcer Answer: a Rationale: An unreasonable fear of an object or situation is known as a phobia. Phobias are characterized by excessive and irrational fear responses to specific stimuli. 119. Classical conditioning is most likely to be involved in which of the involving situations? a. Brian won’t work unless he gets paid. b. Alex trains his dog to “roll over” by offering food rewards. c. Rick feels nervous and sick to his stomach when he sees a black cat, but doesn’t know why. d. John loses weight by buying tickets to see his favorite team play whenever he drops five more pounds. Answer: c Rationale: As noted in the textbook, emotional responses, in particular, are often established through classical conditioning. The other examples are directly tied to operant conditioning procedures. 120. If Wesley is afraid to enter tall buildings because he worries that they will be attacked by terrorists, psychologists would say his fear is most likely the result of: a. habituation b. a phobia c. heritability d. poor self-efficacy Answer: b Rationale: As noted in the textbook, unreasonable fears of objects or situations are called phobias; phobias—such as fear of the dark, fear of being in a closely confined space, and so forth—often are established through classical conditioning. 121. For as long as Brian can remember, he has been fearful of being in high places. Just the idea of climbing stairs or riding in an elevator causes him to be overcome with uncontrollable fear. Brian likely suffers from: a. a phobia b. negative conditioning c. habituation d. reinforcement failure Answer: a Rationale: As noted in the textbook, unreasonable fears of objects or situations are called phobias. 122. Operant conditioning is especially likely to be involved in the development of: a. phobias b. excessive salivation c. habituation d. habits Answer: d Rationale: Operant conditioning, which involves learning through consequences, such as reinforcement or punishment, is especially likely to be involved in the development of habits. Behaviors that are reinforced tend to become more frequent and habitual. 123. Operant conditioning is most closely associated with which of the following? a. production of reflexive responses, such as salivation b. production of emotional responses, such as fearfulness c. the ability to screen meaningless repetitive stimuli out of consciousness d. understanding the effect of consequences that follow a particular behavior Answer: d Rationale: Operant conditioning involves the application or removal of rewards (called reinforcements) and punishments to encourage or discourage us from acting in certain ways. Both reinforcements and punishments constitute consequences that follow a particular behavior. 124. Which of the following is the best example of a partial schedule of reinforcement? a. Every time he cries, Robert’s mother picks him up. b. Vickie has a tantrum every time her mother takes her to the grocery store because once or twice in the past her mother has given in and bought her candy to quiet her down. c. Julie has come to expect that she will be paid for babysitting her little brother because this is what parents always do. d. Jake has a terrible fear of spiders that his therapist has now diagnosed as a phobia. Answer: b Rationale: In a partial schedule of reinforcement, reinforcements occur only occasionally, not every time a behavior occurs. 125. A consequence that decreases the probability that a behavior will be repeated is a technical definition of the term: a. punishment b. threat c. self-efficacy d. partial schedule Answer: a Rationale: As noted in the textbook, punishments decrease the probability that a behavior will be repeated. 126. Systematically reinforcing successive approximations to a desired act defines: a. shaping b. counterconditioning c. stimulus generalization d. systematic desensitization Answer: a Rationale: Shaping involves reinforcing successive approximations to a desired behavior until the target behavior is achieved. It is a method used in operant conditioning to gradually shape complex behaviors. 127. Suppose Sandra has difficulty in concentrating while doing her homework. She decides to reward herself for reading 5 minutes without letting her mind wander. After a week of this, she decides to reward herself only when she reads for 10 minutes without distraction. Finally, she is able to concentrate for 15 minutes at a time without distraction. Sandra’s ability to improve her study behavior is best considered an example of: a. shaping b. classical conditioning c. habituation d. punishment Answer: a Rationale: Shaping involves systematically reinforcing successive approximations to a desired behavior. In this case, Sandra reinforces her successive approximations (studying for 5 minutes) of the desired behavior (studying for 15 minutes without distraction). 128. Learning through the method of “successive approximation” is at the heart of the concept called: a. self-efficacy b. classical conditioning c. partial schedules of reinforcement d. shaping Answer: d Rationale: Learning through the method of successive approximation, where behaviors are reinforced gradually closer to the desired behavior, is at the heart of the concept called shaping. Shaping is a technique used in operant conditioning to establish new behaviors. 129. Rex decides that the only way he will ever be able to work hard enough to pass his chemistry class is to give himself a reward after every chapter he reads and every lab report he turns in on time. His approach to studying is best thought of as an example of: a. classical conditioning b. behavior modification c. habituation d. normative age-graded influences Answer: b Rationale: Behavior modification is a method that uses conditioning procedures—such as reinforcement, reward, and shaping—to change behavior. 130. The application of learning principles in order to change behavior is called: a. EPS: Establishing Partial Schedules b. CC-OC: Classical Conditioning-Operant Conditioning c. ABA: Applied Behavioral Analysis d. Meta-analysis Answer: c Rationale: Applied Behavioral Analysis (ABA) involves the application of learning principles, particularly those of operant conditioning, to change behavior systematically. It is commonly used in various settings, including education, therapy, and rehabilitation. 131. Whitney believes that she is a capable, confident person who can usually succeed in whatever she tries to do. Psychologists would be most likely to conclude that she has: a. a phobia b. a strong sense of self-efficacy c. a comfortable developmental niche d. established a codominant relationship with her parents Answer: b Rationale: Self-efficacy refers to what a person believes he or she is capable of doing in a given situation. Environment in a Broader Context: Family and Culture 132. The unique world experienced by each individual is called that person’s: a. developmental niche b. personal space c. family system d. normative space Answer: a Rationale: The term "developmental niche" refers to the unique combination of environmental factors and experiences that shape an individual's development. It includes aspects such as cultural practices, social relationships, and physical surroundings. 133. If different members of the family experience quite different environments, this would be reflected in: a. a larger shared environment b. a larger nonshared environment c. a harsher developmental niche d. a challenge for self-concept development Answer: b Rationale: Nonshared environment refers to those experiences and relationships that persons do not share. 134. The tendency to assume that one’s own cultural beliefs are normal and those of others are abnormal is referred to as: a. cohesion b. socialization c. ethnocentrism d. indoctrination Answer: c Rationale: Ethnocentrism is the tendency to view one's own cultural group as superior and to judge other cultures based on one's own cultural standards. It involves the assumption that one's own beliefs, values, and customs are normal or correct, while those of other cultures are abnormal or inferior. 135. Patty doesn’t want to hang around with people from the other side of town because she says they are “weird.” Patty’s behavior best reflects the concept involved in: a. ethnocentrism b. self-efficacy c. normative age-graded influences d. normative history-graded influences Answer: a Rationale: Ethnocentrism is the tendency to assume that our own beliefs, perceptions, customs, and values are correct or normal and that those of others are inferior or abnormal. 136. Little Timmy says, “Boys are cool and girls are stupid.” Timmy’s statement reflects the heart of what is meant by the term: a. normative age-graded influences b. nonnormative influences c. self-efficacy d. ethnocentrism Answer: d Rationale: Ethnocentrism is the tendency to assume that our own beliefs, perceptions, customs, and values are correct or normal and that those of others are inferior or abnormal. 137. Which of the following is an example of a normative history-graded influence on development? a. retirement b. career change c. economic depression d. unemployment Answer: c Rationale: An economic depression is an example of a normative history-graded influence on development. These are events or experiences that affect a large group of people within a specific culture or society, often occurring at a particular point in time and influencing the development of individuals who experience them. 138. At age 65, Reggie retired from high school teaching. This change most likely reflects a: a. normative, age-graded influence b. normative, history-graded influence c. nonnormative influence d. normative, gender-graded influence Answer: a Rationale: Normative, age-graded influences refer to the biological and social changes that normally happen at predictable ages (e.g., puberty, menopause, entering school). Most people retire around age 65. 139. Many individuals who grew up during the Great Depression were so devastated by the collapse of the economy that they became distrustful of depositing large sums of money in banks. The Great Depression would best be considered a: a. normative, age-graded influence b. normative, history-graded influence c. nonnormative influence d. normative, economic-graded influence Answer: b Rationale: Normative, history-graded influences refer to the historical events that affect large numbers of individuals at the same time (e.g., wars, depressions, epidemics). The Great Depression is one such example. 140. After Bill's parents’ divorce, he and his mother were forced to move into an apartment and he had to switch schools. The losses Bill experienced following the divorce marked a turning point in his life, because from then on, he did poorly in school. His parents' divorce would be considered a: a. normative, age-graded influence b. normative, history-graded influence c. nonnormative influence d. normative, gender-graded influence Answer: c Rationale: Nonnormative influences refer to the individual environmental factors that do not occur at any predictable time in a person’s life (e.g., divorce, unemployment, career changes). Experiencing one’s parents’ divorce is not an event that can be predicted to occur at a predictable time in a person’s life, if at all. 141. Which of the following is NOT an example of a normative history-graded influence? a. a world-wide disease epidemic b. war c. menopause d. economic depression Answer: c Rationale: Normative, history-graded influences refer to the historical events that affect large numbers of individuals at the same time (e.g., wars, depressions, epidemics). Menopause is an example of a normative, age-graded influence. 142. Which of the following is NOT an example of a normative age-graded influence? a. having children b. puberty c. divorce d. menopause Answer: c Rationale: Normative, age-graded influences refer to the biological and social changes that normally happen at predictable ages (e.g., puberty, menopause, entering school). Divorce does not occur at a predictable age, if at all. 143. Which of the following is MOST likely to be experienced as a normative influence? a. retirement b. career change c. illness d. moving to a new community Answer: a Rationale: Normative influences occur at a predictable time or have a predictable effect on large numbers of people. Most people retire, predictably, around age 65. 144. In general, the impact of nonnormative influences are greatest at which of the following periods of the lifespan: a. in the prenatal period and in infancy b. in early and middle childhood c. in adolescence and early adulthood d. in later adulthood and old age Answer: d Rationale: Nonnormative influences, such as major life events or traumas, have the greatest impact during later adulthood and old age. These events can significantly alter an individual's life trajectory, leading to profound changes in health, relationships, and overall well-being during these stages of life. Changing Perspectives: Genetic Engineering and Cloning 145. If a scientist were to clone a rat, the genetic code in the new rat produced would share what percentage of its genetic code with its parent(s)? a. it would share 50% of its genes with its mother and 50% with its father b. it would share 50% with its mother, but 0% with its father c. it would share 50% with its father, but 0% with its mother d. it would have only one “parent” and would share 100% of its genetic code with it Answer: d Rationale: To clone something means to duplicate it exactly. In the context of genetic engineering, cloning can refer to the replication of DNA segments used to produce drugs like insulin or to the exact duplication of an entire living organism. In the cloning of an animal, the new animal would be an exact duplication of a parent. 146. In agriculture, the traditional practice of genetic engineering is called: a. green engineering b. selective breeding c. cloning d. genetic replication Answer: b Rationale: Selective breeding is the traditional practice of genetic engineering in agriculture. It involves selectively breeding plants or animals with desirable traits to produce offspring with those traits. 147. Generalizing from the text, you should conclude that the primary problem with cloning human beings has to do with: a. ethical issues b. the much greater complexity of the human brain as compared to animal brains c. the financial costs involved d. the long prenatal period that humans experience compared to animals Answer: a Rationale: As an example of an ethical concern, some groups are concerned that even those cloning techniques that stop far short of human replication intrude into what they consider to be the sanctity of life. Current Issues: The New Baby and the Extended Family System 148. Research presented in the text noted that, in comparison to young mothers with ill or premature infants who lived away from their extended family, those who lived with their extended family: a. were less likely to complete their education b. were less likely to keep the job they had before the baby was born c. were less likely to have good parenting skills d. had more self-confidence in their ability to be a good parent Answer: c Rationale: The research presented suggests that young mothers with ill or premature infants who lived with their extended family were less likely to develop good parenting skills compared to those who lived away from their extended family. This indicates the impact of living arrangements on parenting outcomes. 149. Which of the following is the best example of what is usually meant by the term “nuclear family?” a. a mother, father, and children b. grandparents, parents, and children c. any family whose primary breadwinner is the father d. any family with three or more children Answer: a Rationale: The term "nuclear family" typically refers to a family unit consisting of two parents (a mother and a father) and their children. Option a, which includes a mother, father, and children, aligns most closely with this definition. True/False questions: Molecular Genetics 150. To say that genetics and environment interact means that these forces influence each other. Answer: True Rationale: True. The statement accurately reflects the concept of gene-environment interaction, where genetic factors and environmental influences work together and influence each other to shape an individual's traits, behaviors, and development. 151. We share about 98% of our genes with chimpanzees. Answer: True Rationale: True. It is well-established that humans and chimpanzees share approximately 98% of their DNA sequence. This genetic similarity reflects the close evolutionary relationship between humans and chimpanzees, as both species share a common ancestor. 152. In the human body, there are approximately 20 different kinds of cells, which are arranged in different ways to create different tissues and organs. Answer: False Rationale: The human body is comprised of over 200 different kinds of cells. 153. Mitochondria are the “powerhouses” of a cell. Answer: True Rationale: True. Mitochondria are often referred to as the "powerhouses" of a cell because they are responsible for producing adenosine triphosphate (ATP), which is the primary energy currency of the cell. Through a process called cellular respiration, mitochondria generate ATP by breaking down nutrients such as glucose, providing energy for various cellular activities. 154. Scientists have been able to identify markers in the human DNA that distinguishes different races of people. Answer: False Rationale: Traits that are associated with different race-based features, such as skin color, are distributed continuously through the population and there are no “either-or” traits that differentiate different racial groups. Instead, the concept of race is better thought of as a social construct, more closely related to ethnicity than a particular genetic code. 155. There are about one million genes in the human genome. Answer: False Rationale: There are about 20,000 to 25,000 genes in the human genome. 156. The primary function of proteins called antibodies is to speed up the chemical reactions within cells. Answer: False Rationale: The primary function of antibodies is to protect the body from disease. Genes, Chromosomes, and Cell Division 157. Most cells in the human body divide according to the process of mitosis; however, the gametes divide in a process called meiosis. Answer: True Rationale: True. Mitosis is the process of cell division that occurs in somatic cells, resulting in two daughter cells with the same number of chromosomes as the parent cell. In contrast, gametes (sperm and egg cells) are produced through meiosis, a specialized form of cell division that reduces the chromosome number by half, resulting in genetically diverse haploid cells for sexual reproduction. 158. Normal adults have 46 chromosomes contained within each of their body cells. Thus, when a couple’s sperm and ovum unite, the resulting baby will have 92 chromosomes in each body cell. Answer: False Rationale: Normal body cells have 46 chromosomes, except for sperm and egg cell, which have one-half of a normal complement of chromosomes. Thus, when sperm and egg unite, each contributes 23 chromosomes, which join together to make 23 pair, or 46, chromosomes. 159. Most human traits involve polygenic inheritance (multiple genes) rather than a single gene. Answer: True Rationale: True. Polygenic inheritance refers to the inheritance of traits that are controlled by multiple genes, each contributing a small additive effect to the phenotype. Many human traits, such as height, skin color, and intelligence, are influenced by the interaction of multiple genes rather than being determined by a single gene. 160. Blood type is a good example of a sex-linked trait, which means that certain blood types are more common in males than in females. Answer: False Rationale: Blood type is an example of a trait that is codominant, meaning that individuals who carry different alleles inherit the phenotype that is a blending of the two traits carried by parents. 161. Sometimes in the process of meiosis genetic material crosses over from one allele in a chromosome to another. This process results in unique new recombinant alleles. Answer: True Rationale: True. During meiosis, genetic material can undergo crossing over, where segments of chromatids from homologous chromosomes are exchanged. This results in the creation of new combinations of alleles on the chromosomes, leading to genetic variation among gametes and ultimately among offspring. 162. Because there are so many possibilities for how genes can combine in the process of human reproduction, two human parents theoretically could produce hundreds of trillions of genetically unique children. Answer: True Rationale: True. Considering the random assortment of chromosomes during gamete formation, as well as the potential for genetic recombination through crossing over during meiosis, the number of genetically unique combinations possible from two parents is indeed extremely large, theoretically allowing for hundreds of trillions of genetically distinct offspring. 163. Although it was earlier thought that cell mutations were quite rare, more recent research has found that they actually occur quite frequently. Answer: True Rationale: True. Advances in genetic research have revealed that mutations occur more frequently than previously believed. These mutations can arise spontaneously during DNA replication, be induced by environmental factors, or result from errors in cellular processes, contributing to genetic diversity and evolution. 164. It is true that genetic forces sometimes cause people to seek out certain types of environmental situations. Answer: True Rationale: True. Genetic factors can influence individual behaviors and traits, which may predispose individuals to seek out or be drawn to specific environmental situations. For example, genetic predispositions for certain personality traits or interests may influence an individual's preferences for particular environments or activities. 165. The idea that nongenetic factors can influence how genes behave is referred to as “polygenic” influences. Answer: False Rationale: Nongenetic forces that influence gene behavior are called “epigenetic” forces. “Polygenic” is a term meaning that more than one gene is involved in the expression of a trait; an example would be intelligence. Genetic and Chromosomal Disorders 166. Each year in the United States congenital anomalies (or birth defects) affect between 10% and 15% of all births. Answer: False Rationale: Congenital anomalies affect about 3% of the infants born in the United States today. 167. Sex-linked traits occur when the autosomes do not replicate correctly. Answer: False Rationale: Sex-linked traits occur when the gametes do not replicate correctly. 168. Hemophilia and color blindness are examples of abnormalities associated with genes on the sex chromosomes. Answer: True Rationale: True. Both hemophilia and color blindness are genetic disorders caused by mutations in genes located on the sex chromosomes. Hemophilia is typically linked to genes on the X chromosome, while color blindness is commonly associated with genes on the X chromosome as well. Since these disorders are sex-linked, they often exhibit different patterns of inheritance depending on the individual's sex and the presence of certain alleles on the sex chromosomes. 169. Because the genes that code for Fragile X disorder are on the X chromosome, females are affected much more often and more seriously than males. Answer: False Rationale: Fragile X syndrome is a trait carried on the X chromosome, but it is more commonly diagnosed in males, since they do not have the corresponding chromosome site on the Y-chromosome that could carry a dominant version of this allele. 170. Down syndrome is an example of an autosomal disorder. Answer: True Rationale: True. Down syndrome is caused by the presence of an extra copy of chromosome 21, which is one of the autosomes (non-sex chromosomes). It is not caused by abnormalities in the sex chromosomes (X and Y). Therefore, Down syndrome is indeed an example of an autosomal disorder. 171. Gene imprinting results in the situation in which an extra chromosome or piece of chromosome is included in a person’s genotype. Answer: False Rationale: Gene imprinting is a phenomenon in which a person’s phenotype depends not on which genes are inherited, but rather on whether the genes for a trait come from the mother versus the father. 172. Mitochondrial disorders involve DNA that is inherited from the mother. Answer: True Rationale: True. Mitochondrial disorders are caused by mutations in the DNA of mitochondria, which are inherited exclusively from the mother. This is because the mitochondria in the sperm are usually destroyed upon fertilization, while the mitochondria in the egg are passed on to the offspring, making mitochondrial DNA inheritance maternally-linked. 173. Something that recombinant gene technologies have in common is that they involve extracting some genetic material from cells and reintroducing it into different cells. Answer: True Rationale: True. Recombinant gene technologies, such as gene cloning and genetic engineering, involve the manipulation of genetic material. This often includes the extraction of DNA from cells, manipulation of the DNA in vitro (in a laboratory setting), and reintroduction of the modified DNA into different cells. These techniques are commonly used in biotechnology and genetic engineering applications. Behavior Genetics 174. Once the human genome is completely mapped, the field of behavior genetics will no longer be useful. Answer: False Rationale: Behavior genetics will always be useful because it considers not only the person’s genes but also how the environment modifies their action. 175. If a trait has a heritability that is greater than zero, then the concordance rate for identical twins will be greater than for fraternal twins. Answer: True Rationale: True. Heritability refers to the proportion of variance in a trait that is attributable to genetic factors within a specific population. When a trait has a heritability greater than zero, it indicates that genetic factors contribute to individual differences in that trait. Since identical twins share 100% of their genetic material, they are more likely to have similar traits compared to fraternal twins, who share, on average, 50% of their genetic material. Therefore, if a trait has a heritability greater than zero, the concordance rate (similarity in traits) for identical twins will be greater than for fraternal twins. Environmental Influences and Contexts 176. Habituation is the learning process that is usually associated with the learning of emotional responses, including phobias. Answer: False Rationale: Phobias and other emotional responses are typically learned through classical conditioning processes, not habituation. 177. When applied behavior analysis programs involve a slow, progressive set of expectations that become more demanding over time, this is called shaping. Answer: True Rationale: True. Shaping is a technique used in applied behavior analysis (ABA) where behaviors are gradually modified or shaped by reinforcing successive approximations towards the desired behavior. This involves breaking down the target behavior into smaller, achievable steps and reinforcing each step as it approximates the desired behavior. As the individual successfully achieves each step, the expectations become more demanding over time, leading to the development of the desired behavior. Environment in a Broader Context: Family and Culture 178. The nonshared environment for identical twins raised in the same home would be zero. Answer: False Rationale: Even identical twins do not experience the same environment, thus they do experience at least some non-shared environmental circumstances unique to each individual. 179. Only the most primitive cultures exhibit ethnocentrism, which is the working assumption that one’s own beliefs, perceptions, customs, and values are correct and that those of others are inferior. Answer: False Rationale: Ethnocentrism, which is correctly defined in this question, is present to some degree in all cultures. 180. The Great Depression is a good example of a nonnormative, history-graded influence. Answer: False Rationale: The Great Depression was an event that was common to all people living at that period of time. Therefore it is a good example of a normative history-graded influence on development. 181. Graduating from high school is a good example of a normative age-graded influence. Answer: True Rationale: True. Normative age-graded influences are events or experiences that are typical or expected at certain ages within a culture or society. Graduating from high school is a significant milestone that is typically achieved around the same age by most individuals in a given society. It represents a normative transition from adolescence to young adulthood and is influenced by social expectations and educational norms. Short Answer questions: Molecular Genetics 182. What are the three different ways that nucleotides in the DNA molecule can determine the particular way that individuals differ from each other? Answer: Nucleotides in the DNA molecule can determine individual differences through variations in the sequence of bases, which can lead to differences in proteins produced, gene regulation, and ultimately, phenotypic traits. Genes, Chromosomes, and Cell Division 183. In your own words, explain the difference between a gene and a chromosome. Answer: A gene is a specific sequence of DNA that contains instructions for building proteins or RNA molecules, while a chromosome is a long strand of DNA wrapped around proteins called histones, which carries many genes along with regulatory elements and other non-coding sequences. 184. Identify two ways that the processes of mitosis and meiosis differ. Answer: Mitosis is a process of cell division that results in two identical daughter cells with the same number of chromosomes as the parent cell, used for growth, repair, and asexual reproduction. Meiosis, on the other hand, is a specialized type of cell division that results in four non-identical daughter cells with half the number of chromosomes as the parent cell, used in sexual reproduction to produce gametes. Additionally, while mitosis occurs in somatic cells, meiosis occurs only in germ cells. 185. Give an example of the three genotypes that could exist for a single-gene trait, such as eye color. What phenotype is associated with each of these three genotypes? Answer: For a single-gene trait like eye color, the three genotypes could be represented by homozygous dominant (BB), heterozygous (Bb), and homozygous recessive (bb). The phenotype associated with each genotype would be brown eyes for BB, brown eyes (with potential for carrying the recessive allele) for Bb, and blue eyes for bb. 186. How does a trait governed by polygenic inheritance differ from one governed by a single gene? Give an example of a trait determined by each of these processes. Answer: A trait governed by polygenic inheritance is determined by the interaction of multiple genes, each contributing small effects to the phenotype. These traits often exhibit a continuous range of variation. For example, human height is influenced by multiple genes, and variations in these genes collectively contribute to the range of heights observed in populations. In contrast, a trait governed by a single gene follows Mendelian inheritance patterns and typically exhibits discrete phenotypic outcomes based on the presence or absence of specific alleles at that gene locus. An example of such a trait is Mendel's pea plant trait for seed color, where the presence of a dominant allele results in yellow seeds, and the presence of a recessive allele results in green seeds. 187. Define what is meant by “independent assortment” as this term is applied to how meiosis occurs. Answer: Independent assortment refers to the random arrangement and separation of homologous chromosome pairs during meiosis I. This process results in the inheritance of one allele for a particular gene independently of alleles for other genes. As a result, the combination of alleles in gametes is random and leads to genetic diversity in offspring. 188. Describe what is meant by the term “gene-environment interaction,” giving an example to demonstrate your answer. Answer: Gene-environment interaction refers to the phenomenon where the expression of genetic traits is influenced by environmental factors. In other words, the effect of genes on a phenotype depends on the specific environmental conditions an individual experiences. For example, consider the interaction between genes and diet in determining cholesterol levels. Certain individuals may possess genetic variants that predispose them to higher cholesterol levels. However, the impact of these genetic factors on actual cholesterol levels may vary depending on factors such as dietary intake of saturated fats. Individuals with the same genetic predisposition may exhibit different cholesterol levels depending on their dietary habits. 189. Describe how nongenetic segments of DNA can influence the expression of genetic traits. Answer: Nongenetic segments of DNA, such as regulatory elements and epigenetic modifications, can influence the expression of genetic traits by regulating the activity of genes. Regulatory elements, like enhancers and promoters, interact with specific regions of DNA to control the transcription of nearby genes. Epigenetic modifications, such as DNA methylation and histone acetylation, can alter the accessibility of DNA to transcriptional machinery, thereby affecting gene expression. These nongenetic factors can act as switches to turn genes on or off, modulating the expression of genetic traits without altering the underlying DNA sequence. Genetic and Chromosomal Disorders 190. Explain why sex-linked traits are more common among males than females. Answer: Sex-linked traits are more common among males due to the inheritance pattern of sex chromosomes. Males have one X and one Y chromosome, while females have two X chromosomes. If a male inherits a recessive allele for a sex-linked trait on the X chromosome from his mother, he will exhibit the trait because he lacks a corresponding dominant allele on the Y chromosome to mask its expression. In females, a recessive allele on one X chromosome can often be masked by the presence of a dominant allele on the other X chromosome, making the expression of the trait less likely. 191. Suggest two ways that mitochondrial disorders are different from other types of genetic disorders. Answer: Mitochondrial disorders are unique in that they are maternally inherited, meaning they are passed down from the mother. Unlike nuclear DNA, which is inherited from both parents, mitochondrial DNA (mtDNA) is exclusively inherited from the mother. Additionally, mitochondrial disorders often affect energy production within cells since mitochondria are responsible for generating energy in the form of ATP. This can lead to a wide range of symptoms affecting tissues and organs with high energy demands. 192. Suggest two ways in which genetics counselors can be of use to couples who are thinking about having a baby. Answer: Genetics counselors can provide information and guidance regarding the likelihood of passing on genetic disorders to offspring based on family history and genetic testing results. They can also offer emotional support and help couples navigate the decision-making process regarding options such as prenatal testing, assisted reproductive technologies, or adoption. 193. Describe how retroviruses are useful in gene therapy. Answer: Retroviruses are useful in gene therapy because they can deliver therapeutic genes into target cells' DNA. Retroviruses have the ability to integrate their genetic material into the host cell's genome, allowing them to permanently modify the cell's DNA. Scientists can engineer retroviruses to carry therapeutic genes and use them to replace or supplement defective genes in patients with genetic disorders. This approach holds promise for treating a wide range of genetic diseases by providing long-term or permanent correction of genetic defects. Behavior Genetics 194. Why will the field of behavioral genetics always be of use, even if the human genome is completely mapped? Answer: The field of behavioral genetics will remain relevant because it explores the complex interplay between genetics and environmental factors in shaping behavior. While the human genome provides invaluable insights into the genetic basis of behavior, it is only one piece of the puzzle. Understanding how genes interact with environmental influences, developmental factors, and individual experiences is crucial for unraveling the complexities of behavior. Additionally, ongoing research in behavioral genetics can inform personalized approaches to healthcare, education, and social policy by identifying genetic predispositions and environmental factors that influence behavior. 195. Suppose that a particular trait results from the interaction of hereditary and environmental forces. Describe the expected results from a typical adoption study of the heritability of this trait. Answer: In a typical adoption study investigating the heritability of a trait influenced by both genetics and environment, researchers would compare the trait expression in adopted individuals to that of their biological and adoptive relatives. If the trait has a significant hereditary component, adopted individuals would be more similar to their biological relatives in trait expression than to their adoptive relatives. However, if environmental factors play a predominant role, adopted individuals would exhibit greater similarity to their adoptive relatives. The study would reveal insights into the relative contributions of genetics and environment to the manifestation of the trait. Environmental Influences and Contexts 196. Give an original example that portrays the kind of learning called habituation. Answer: Imagine a person moving to a house near a train station. Initially, the loud noise of passing trains disrupts their sleep and concentration. However, as they continue living there, they gradually become accustomed to the noise. Eventually, they hardly notice it, even when trains pass by frequently. This scenario illustrates habituation, where repeated exposure to a stimulus leads to a decreased response. 197. What is the primary difference between a reinforcer and a punishment, according to operant conditioning theory? Answer: In operant conditioning theory, the primary difference between a reinforcer and a punishment lies in their effects on behavior. A reinforcer is any stimulus that, when presented following a behavior, increases the likelihood of that behavior recurring. Conversely, a punishment is a stimulus that, when presented following a behavior, decreases the likelihood of that behavior occurring again. Essentially, reinforcers strengthen behavior, while punishments weaken it. 198. Give an example of a behavior that is learned or maintained according to a partial schedule of reinforcement. Answer: An example of a behavior learned or maintained according to a partial schedule of reinforcement is a salesperson's commission-based income. The salesperson receives a variable ratio of reinforcement, as they may make a sale after various numbers of pitches or attempts. Despite occasional rejections, the potential for a lucrative sale keeps them motivated to continue their sales efforts. Environmental Influences and Contexts 199. Give an example of a statement that reflects an ethnocentric viewpoint. Answer: • Example: "Our cultural practices are superior to those of others because they are based on rationality and progress." 200. Give an example of a normative age-graded influence, an example of a normative history-graded influence, and an example of a nonnormative influence in human development. Answer: • Normative age-graded influence: Puberty is a normative age-graded influence as it typically occurs around the same age for most individuals and affects various aspects of development such as physical growth and hormonal changes. • Normative history-graded influence: World War II is an example of a normative history-graded influence because it had widespread effects on the lives of individuals who lived through it, shaping their experiences, values, and opportunities. • Nonnormative influence: Winning the lottery is a nonnormative influence as it is an event that occurs unpredictably and affects individuals in unique ways, such as sudden wealth impacting their lifestyle and choices. Essay questions: Molecular Genetics 201. Describe the structure of the DNA molecule and explain how the entire genetic code is constructed with only four different bases: adenine, thymine, cytosine, and guanine. Answer: The DNA molecule is a double helix structure consisting of two strands of nucleotides. Each nucleotide consists of a phosphate group, a sugar molecule (deoxyribose), and one of four nitrogenous bases: adenine (A), thymine (T), cytosine (C), and guanine (G). Adenine pairs with thymine, and cytosine pairs with guanine through hydrogen bonds, forming complementary base pairs. The sequence of these bases along the DNA strands serves as the genetic code, with the specific order of bases encoding instructions for building proteins and regulating cellular processes. Despite the simplicity of having only four bases, the arrangement and sequence of these bases allow for an incredibly diverse array of genetic information. 202. Discuss how the concept of “race” is typically considered from a genetic point of view. In your discussion, answer the questions: Are there “racial” differences that are coded in the genes? Answer: From a genetic standpoint, the concept of "race" is often viewed as a social construct rather than a biological reality. While there may be observable physical differences among populations that are often associated with racial categories, such as skin color or facial features, these differences are primarily due to adaptations to different environments rather than inherent genetic distinctions between racial groups. Genetic studies have shown that there is more genetic variation within racial groups than between them. The concept of race does not align neatly with genetic variation because human populations have intermixed throughout history, leading to genetic exchange and shared ancestry among diverse populations. Therefore, while there may be variations in certain genetic traits associated with geographical ancestry, such as lactose tolerance or susceptibility to certain diseases, these differences do not neatly correspond to traditional racial categories. Thus, "racial" differences are not coded in the genes in the sense of discrete, well-defined genetic variations that uniquely distinguish one racial group from another. Genes, Chromosomes, and Cell Division 203. Describe what a karyotype of the chromosomes of a typical person looks like. Include in your answer an explanation of the distinction between the autosomes and the sex chromosomes. Answer: A karyotype of the chromosomes of a typical person typically consists of 22 pairs of autosomes and one pair of sex chromosomes, totaling 46 chromosomes in total. Autosomes are chromosomes that are not involved in determining an individual's sex and are found in both males and females. They are numbered from 1 to 22 based on their size. Sex chromosomes, on the other hand, determine an individual's sex. In females, the sex chromosomes are homologous and are designated as XX, while in males, one sex chromosome is an X chromosome and the other is a Y chromosome, designated as XY. The presence or absence of the Y chromosome determines whether an individual develops as male or female. 204. What occurs during the process of mitosis and the process of meiosis? How do the processes of mitosis and meiosis differ? Answer: Mitosis is a process of cell division that results in two daughter cells that are genetically identical to the parent cell. During mitosis, a single cell undergoes a series of stages, including prophase, metaphase, anaphase, and telophase, ultimately leading to the division of the nucleus and cytoplasm. Mitosis is involved in growth, development, and tissue repair. On the other hand, meiosis is a specialized form of cell division that occurs in germ cells (cells that give rise to gametes) and results in the formation of haploid gametes (sperm and eggs). Meiosis involves two rounds of division (meiosis I and meiosis II), resulting in four daughter cells, each with half the number of chromosomes as the parent cell. Meiosis introduces genetic diversity by shuffling alleles through processes such as crossing over and independent assortment. Unlike mitosis, which produces genetically identical cells, meiosis generates genetically diverse cells. 205. Define the concept of “allele” and suggest the allele configuration of a homozygous versus a heterozygous trait. Answer: An allele is a variant form of a gene that arises by mutation and is found at a specific position on a chromosome. Alleles can exist in different forms and can produce variations in inherited traits. In a homozygous trait, an individual carries two identical alleles for a particular gene locus, whether they are both dominant (e.g., AA) or both recessive (e.g., aa). In contrast, a heterozygous trait occurs when an individual carries two different alleles for a particular gene locus (e.g., Aa), where one allele may be dominant and the other recessive. In this case, the dominant allele usually determines the phenotype, while the recessive allele remains unexpressed. 206. Give an example of a sex-linked trait and describe why such traits are more frequently observed in males than females. Answer: An example of a sex-linked trait is color blindness, which is more frequently observed in males than females. This is because the gene responsible for color vision (located on the X chromosome) is recessive, and males have only one X chromosome. Therefore, if a male inherits the recessive allele for color blindness from his mother, he will exhibit the trait since he lacks a corresponding dominant allele on the Y chromosome to mask its expression. In females, a recessive allele on one X chromosome can often be masked by the presence of a dominant allele on the other X chromosome, making the expression of the trait less likely. 207. Explain how epigenetic processes provide an explanation for gene-environment interactions and give an example to demonstrate your answer. Answer: Epigenetic processes involve modifications to DNA or associated proteins that can influence gene expression without altering the underlying DNA sequence. These modifications can be influenced by environmental factors, thus providing a mechanism for gene-environment interactions. For example, DNA methylation is an epigenetic modification that involves the addition of methyl groups to certain regions of DNA, often resulting in the suppression of gene expression. Environmental factors such as diet, stress, and exposure to toxins can influence DNA methylation patterns. An example demonstrating this is the effect of maternal diet on offspring health. Studies have shown that a mother's diet during pregnancy can influence the epigenetic patterns of her offspring, affecting their susceptibility to various diseases later in life. For instance, inadequate maternal nutrition can lead to altered DNA methylation patterns in the fetus, predisposing the offspring to conditions like obesity, diabetes, or cardiovascular disease. This illustrates how epigenetic processes mediate the interaction between genetic predisposition and environmental factors in shaping an individual's health outcomes. Genetic and Chromosomal Disorders 208. Describe what services are offered by genetics counselors and suggest why a couple might choose to seek out these services. Answer: Genetics counselors offer a range of services including assessing the risk of inherited conditions, explaining genetic testing options, interpreting test results, providing emotional support, and discussing reproductive options. A couple might seek out these services if they are planning to start a family and want to understand their genetic risks, especially if they have a family history of genetic disorders or if they are concerned about passing on certain traits to their children. Genetics counselors can help couples make informed decisions about family planning and prenatal testing. 209. Give an example of a genetic disorder and of a chromosomal disorder. What is the difference between these two types of disorders? Answer: An example of a genetic disorder is cystic fibrosis, which is caused by mutations in the CFTR gene and leads to the production of thick mucus in the lungs and other organs. A chromosomal disorder example is Down syndrome, which is caused by an extra copy of chromosome 21. The primary difference between these two types of disorders is their underlying cause: genetic disorders result from mutations or abnormalities in individual genes, while chromosomal disorders involve changes in the structure or number of chromosomes. 210. Explain how recombinant technology can be used as part of a gene therapy program. Answer: Recombinant technology can be utilized in gene therapy programs to introduce functional genes into cells to treat genetic disorders. This process involves isolating the gene of interest, modifying it if necessary, and then inserting it into a vector, such as a virus or plasmid. The modified vector carrying the functional gene is then introduced into the patient's cells, where it can integrate into the genome and express the therapeutic gene. By replacing or supplementing defective genes with functional ones, gene therapy aims to correct the underlying genetic cause of disorders and restore normal cellular function. Behavior Genetics 211. Define what is meant by “concordance” and describe how a concordance study would be conducted using twins. Answer: • Concordance refers to the degree of similarity or agreement between individuals with respect to a particular trait or condition. In genetics, it often refers to the presence of the same trait or condition in both members of a pair of individuals (e.g., twins) or in family members. In a concordance study using twins, researchers would assess the presence or absence of a trait or condition in pairs of twins, such as identical (monozygotic) twins or fraternal (dizygotic) twins. The concordance rate is then calculated as the proportion of twin pairs in which both twins share the trait or condition. 212. Explain the rationale for using adoption studies and twin studies in learning about genetic influences on behavior. Answer: • Adoption studies and twin studies are valuable in understanding genetic influences on behavior because they allow researchers to disentangle the effects of genetics and environment. In adoption studies, researchers compare the similarity of adopted children to their biological parents (genetic influence) and their adoptive parents (environmental influence) to determine the relative contributions of genetics and environment to behavioral traits. Twin studies, particularly comparing identical (monozygotic) twins who share 100% of their genes to fraternal (dizygotic) twins who share about 50% of their genes, allow researchers to estimate the heritability of traits by comparing the resemblance of twins for specific behaviors or characteristics. These studies provide insights into the extent to which genetics contribute to the variation observed in behavioral traits. Environmental Influences and Contexts 213. Describe how a phobia would be explained, using a classical conditioning model. Answer: In a classical conditioning model, a phobia can be explained as a learned association between a neutral stimulus and a fear response. For example, if someone experiences a traumatic event involving a particular object or situation (unconditioned stimulus), they may develop a fear response (unconditioned response). Through classical conditioning, if the neutral stimulus (such as the object or situation) is repeatedly paired with the unconditioned stimulus, it can become a conditioned stimulus that elicits the fear response even in the absence of the original trauma. This leads to the development of a phobia. 214. Suppose you want to improve your study habits. Describe how an applied behavior analysis program based on shaping could be used to help you accomplish this goal. Answer: An applied behavior analysis program based on shaping could be used to improve study habits by gradually reinforcing behaviors that lead to effective studying. For example, if someone struggles with studying for long periods, the program might start by reinforcing shorter study sessions and gradually increasing the duration over time. Positive reinforcement, such as rewards or praise, can be provided for each successful study session, encouraging the individual to continue and reinforcing the desired behavior. Through shaping, the person's study habits can be systematically modified and improved. 215. Explain the difference between the terms self-concept and self-efficacy. Answer: Self-concept refers to the overall perception or understanding that an individual has about themselves, including beliefs, attitudes, and perceptions about their own identity, abilities, and characteristics. It encompasses how one views themselves across various domains, such as social, academic, and personal. On the other hand, self-efficacy refers to a person's belief in their ability to succeed in specific situations or accomplish particular tasks. It is more focused on confidence in one's own capabilities to perform certain actions or achieve goals. Self-efficacy influences motivation, effort, and persistence in the face of challenges, as individuals with higher self-efficacy are more likely to engage in goal-directed behaviors and persevere in the face of obstacles. Environment in a Broader Context: Family and Culture 216. Give an example of ethnocentric thinking and explain why researchers in the area of human development must be especially aware of its influence as they formulate theories. Answer: Ethnocentric thinking involves viewing one's own cultural group as superior to others and judging other cultures based on the standards and values of one's own culture. An example of ethnocentric thinking could be when researchers from a particular cultural background assume that their cultural norms, practices, or behaviors are universally applicable without considering the diversity of human experiences across cultures. In the field of human development, researchers must be aware of ethnocentric thinking because it can lead to biased interpretations and generalizations about human behavior and development. Ignoring cultural diversity can result in the development of theories that are not applicable or relevant to individuals from different cultural backgrounds, ultimately limiting our understanding of human development. 217. Distinguish between normative age-graded influences and normative history-graded influences and give an example of each. Answer: Normative age-graded influences are events or experiences that are typical for people of a certain age group and are often associated with biological or social aging processes. These influences occur at predictable ages and affect large segments of the population similarly. An example of a normative age-graded influence is puberty, which typically occurs during adolescence and involves biological changes such as growth spurts and hormonal changes that are experienced by most individuals in that age group. Normative history-graded influences, on the other hand, are events or experiences that are common to a particular generation or historical era. These influences shape the experiences of individuals who live through them and may have long-lasting effects on their development. An example of a normative history-graded influence is the Great Depression, which affected individuals who lived through that era and influenced their economic opportunities, lifestyles, and psychological well-being. 218. Describe how normative age-graded influence, normative history-graded influences, and nonnormative events change in their relative influence on development across the lifespan. Which are most important in early life? Which are most important in later life? Answer: Normative age-graded influences, such as biological changes associated with aging and social transitions (e.g., starting school, retirement), are most influential in early life as they set the trajectory for development and establish developmental milestones. As individuals age, normative history-graded influences become increasingly important, as they shape the experiences and opportunities available to them within the context of their historical and cultural milieu. Nonnormative events, which are unique and unpredictable events that may have significant impacts on an individual's life, tend to become more influential in later life as individuals accumulate a variety of experiences and encounter more variability in life circumstances. In early life, normative age-graded influences such as genetic predispositions and family environments play a crucial role, while in later life, normative history-graded influences such as societal changes and historical events become more prominent in shaping development. Test Bank for Understanding Human Development Wendy L. Dunn, Grace J. Craig 9780205989522, 9780135164204, 9780205233878, 9780205753079