Chapter 03 Forming a New Life: Conception, Heredity, and Environment Multiple Choice Questions 1. Bronfenbrenner's _____________ approach examines the layers of social systems and how these layers interact. A. interactionist B. bioecological C. behaviorist D. cognitive Answer: B. bioecological 2. Which of the following factors can have vast consequences on a child's development? A. Whether the birth comes about through normal or extraordinary means B. Whether the birth is welcome or unwanted C. How old the parents are when the child is conceived or adopted D. All of the above Answer: D. All of the above 3. _____________ suggested that the production of male babies was the natural order of things and that a female came about only if development was disturbed. A. Bronfenbrenner. B. Aristotle. C. Skinner. D. Mendel. Answer: B. Aristotle. 4. The union of sperm and ovum to produce a zygote is known as A. the two-seed theory. B. ovulation. C. attachment. D. fertilization. Answer: D. fertilization. 5. In fertilization, the male and the female gametes combine to create a single cell called a(n) _____________, which then duplicates itself again and again to become a baby. A. zygote B. ovum C. sperm D. follicle Answer: A. zygote 6. Ovulation refers to the A. fertilization of an ovum by a sperm. B. expulsion of an ovum from the ovary. C. passage of an ovum through the vagina and out of the woman's body. D. absorption of an ovum by the woman's white blood cells. Answer: B. expulsion of an ovum from the ovary. 7. Fertilization usually takes place in the _____________ as the ovum make the trip from the ovary to the uterus. A. womb B. fallopian tube C. ovaries D. cervix Answer: B. fallopian tube 8. Sperm are produced in the _____________ at a rate of several hundred million a day and are ejaculated in the semen during sexual climax. A. ovary B. cervix C. testes D. uterus Answer: C. testes 9. Daniel and Nellie are hoping to maximize Nellie's chances of becoming pregnant. When should they have intercourse? A. between the 6th and 21st days of the menstrual cycle B. 5 days after the onset of ovulation C. 14 days after the onset of menstruation D. 28 days after the onset of menstruation Answer: A. between the 6th and 21st days of the menstrual cycle 10. Infertility is the inability to conceive after _____________ months of trying to have a baby. A. 3 to 6 B. 6 to 9 C. 9 to 12 D. 12 or more Answer: D. 12 or more 11. A common female cause of infertility is A. underproduction of ova. B. abnormal ova. C. blockage of the fallopian tube. D. disease of the uterine lining, which prevents implantation of the fertilized ovum. Answer: C. blockage of the fallopian tube. 12. The most common cause of infertility in men is A. low sperm production. B. impotence. C. use of over-the-counter medications. D. premature ejaculation. Answer: A. low sperm production. 13. Which of the following is NOT true about infertile couples? A. A common cause in females is blockage of the fallopian tubes. B. Drug therapy can sometimes correct the problem. C. Hormone treatment may raise a man's sperm count. D. Surgical treatments are ineffective. Answer: D. Surgical treatments are ineffective. 14. Dan and Fiona have decided to utilize technology to overcome their infertility problems. They opt for a procedure in which a mature ovum is surgically removed, fertilized in a laboratory dish, and then implanted in the woman's uterus. This technique is called A. artificial insemination. B. in vitro fertilization. C. gamete intrafallopian transfer. D. zygote intrafallopian transfer. Answer: B. in vitro fertilization. 15. Fred and Wilma have discovered that their infertility is due to Fred's extremely low sperm count. In an attempt to get pregnant, Wilma has a doctor inject a collection of her husband's sperm directly into her cervix. This procedure is called A. in vitro fertilization. B. sperm transfer. C. artificial insemination. D. ovum transfer. Answer: C. artificial insemination. 16. Medical technology is now able to offer couples several methods of bypassing the normal process of conception. These methods include A. ovum transfer. B. artificial insemination. C. in vitro fertilization. D. all of the above. Answer: D. all of the above. 17. The science of genetics focuses on the A. inherited factors that affect development. B. effects of environmental influences on phenotypic development. C. development of abnormal, rather than normal, behaviors and traits. D. processes involved in fertilization. Answer: A. inherited factors that affect development. 18. Stacy wants to learn more about the sequence of base parts within DNA that determine inherited characteristics. Stacy is interested in A. autosomes. B. multifactorial transmission. C. genome imprinting. D. the genetic code. Answer: D. the genetic code. 19. The chemical that carries inherited instructions for the development of all cellular forms of life is called A. a teratogenic substance. B. adenosine monophosphate. C. arachidonic acid. D. deoxyribonucleic acid. Answer: D. deoxyribonucleic acid. 20. The _____________ is the basic unit that determines inherited characteristics. A. zygote B. gene C. follicle D. gamete Answer: B. gene 21. Which of the following are made up of DNA (deoxyribonucleic acid)? A. Gametes B. Gymnosperm C. Androsperm D. Genes Answer: D. Genes 22. How many pairs of chromosomes does a typically developing human being have? A. 22 B. 23 C. 44 D. 46 Answer: B. 23 23. A cell that has divided through mitosis possesses _____________ chromosomes, whereas a cell that has undergone meiosis possesses _____________ chromosomes. A. 23 pairs of ; 23 B. 46 pairs of ; 46 C. 23 ; 46 D. 23 chromosomes; 23 pairs of Answer: A. 23 pairs of ; 23 24. The process of cell division that produces copies of cells with 46 chromosomes is called A. diffusion. B. meiosis. C. translocation. D. mitosis. Answer: D. mitosis. 25. Meiosis A. results in two cells, each with 46 chromosomes. B. reduces the number of chromosomes by half. C. refers to the addition of an extra 21st chromosome. D. is the process by which the egg and sperm combine. Answer: B. reduces the number of chromosomes by half. 26. Each ovum possesses _____________ chromosomes, and each sperm possesses _____________ chromosomes. A. 23 ; 46 B. 46 ; 23 C. 23 pairs of ; 26 pairs of D. 23 ; 23 Answer: D. 23 ; 23 27. Child A's sex chromosomes are XX, and Child B's sex chromosomes are XY. Child A is a(n) _____________ and Child B is a(n) _____________. A. identical twin; fraternal twin B. fraternal twin; identical twin C. boy; girl D. girl; boy Answer: D. girl; boy 28. Harry's wife is pregnant with a child whose sex chromosome is XY. Harry and his wife are A. heterozygous. B. having a girl. C. having a boy. D. homozygous. Answer: C. having a boy. 29. The chromosomes that do NOT determine sex are called A. zygotes. B. genes. C. gametes. D. autosomes. Answer: D. autosomes. 30. Lewis has wanted a son for as long as he can remember. He has put a great deal of pressure on his pregnant wife. She constantly reminds him that that the sex of the child was determined at conception by the A. genotype of the autosomes of the ovum. B. genotype of the sex chromosomes of the ovum. C. genotype of the sperm that fertilized the ovum. D. phenotype of the sperm that fertilized the ovum. Answer: C. genotype of the sperm that fertilized the ovum. 31. The sex of a child is determined by the sex chromosomes of A. the mother. B. the father. C. both the mother and the father. D. neither the mother nor the father. Answer: B. the father. 32. The X and Y chromosomes are referred to as the A. sex chromosomes. B. autosomes. C. DNA. D. meiotic autosomes. Answer: A. sex chromosomes. 33. During the 1860s, Gregor Mendel conducted experiments that laid the foundation for understanding A. patterns of inheritance. B. intelligence. C. meiosis and mitosis. D. prenatal development. Answer: A. patterns of inheritance. 34. According to Mendel's findings, A. genes occur singly, never in pairs. B. genes do not have fixed positions on chromosomes. C. individual traits blend into one another. D. hereditary traits are transmitted separately. Answer: D. hereditary traits are transmitted separately. 35. Genes that produce alternative expressions of a trait are called A. gametes. B. alleles. C. autosomes. D. karyotypes. Answer: B. alleles. 36. If Ekaterina is homozygous for a particular trait, what will she pass on to her offspring? A. only one kind of gene for that trait B. either of two kinds of genes for that trait C. a sex-linked gene for that trait D. no gene for that trait Answer: A. only one kind of gene for that trait 37. Matu received identical genes for hair color from each of his parents. We would say that Matu is _____________ for that trait. A. homozygous B. monozygous C. heterozygous D. dizygous Answer: A. homozygous 38. If Carol and Robert both pass on the gene for red hair, their child will have red hair. This is an example of _____________ inheritance. A. dominant B. recessive C. sex-linked D. multiple-allele Answer: B. recessive 39. If Darla has albinism but neither of her parents exhibit this inherited condition, the trait must be _____________ and Darla's genotype for this trait is _____________. A. dominant; homozygous B. recessive; homozygous C. dominant; heterozygous D. recessive; heterozygous Answer: B. recessive; homozygous 40. Ulrich is heterozygous for a trait; therefore, he displays the _____________ trait in his phenotype. A. recessive B. dominant C. dominant-recessive D. genotypic Answer: B. dominant 41. Suzanne has brown eyes but also carries a gene for blue eyes. Suzanne is _____________ for the trait of eye color. A. homozygous B. unizygous C. monozygous D. heterozygous Answer: D. heterozygous 42. Permanent genetic alterations that may produce harmful characteristics are called A. transmissions. B. mutations. C. dominant-recessive alterations. D. selective alterations. Answer: B. mutations. 43. Melvin grew up near the Three Mile Island nuclear plant when the meltdown occurred. An analysis of his genetic material indicates changes that are consistent with radiation exposure. The term that describes such genetic or chromosomal alteration is called A. mutation. B. transmission. C. transduction. D. selective alteration. Answer: A. mutation. 44. An individual's _____________ consists of that individual's observable traits; an individual's _____________ is his/her underlying genetic pattern. A. dominant inheritance; heterozygosis B. dominant inheritance; homozygosis C. genotype; phenotype D. phenotype; genotype Answer: D. phenotype; genotype 45. Petra would like to replicate herself. However, she needs to realize that, although cloning can produce identical _____________, it cannot produce identical _____________. A. phenotypes; genotypes B. heredity; environments C. genotypes; phenotypes D. genotypes; alleles Answer: C. genotypes; phenotypes 46. Louise's blue eyes and petite frame are observable characteristics and are part of her A. alleles. B. genetic imprint. C. phenotype. D. genotype. Answer: C. phenotype. 47. Brooklyn has curly hair but carries a gene for straight hair. Her phenotype is A. curly hair. B. straight hair. C. unknown. D. her total genetic makeup. Answer: A. curly hair. 48. When the police ask you to give a description of an assailant and you say that she is tall with black, curly hair, you are describing the assailant's A. incomplete dominance. B. genetic pattern. C. phenotype. D. genotype. Answer: C. phenotype. 49. The differential expression of certain genetic traits is known as A. genome imprinting. B. genome splitting. C. chromosome imprinting. D. chromosome splitting. Answer: A. genome imprinting. 50. Which of the following statements best describes the concept of multifactorial transmission? A. One or two genes determine many obvious psychological characteristics, such as intelligence. B. Offspring with multiple recessive genes often do not survive to transmit those genes. C. The environment and many different genes interact to determine most psychological traits. D. The expression of dominant genes is solely influenced by hereditary factors, whereas the expression of recessive genes is strongly influenced by environmental factors. Answer: C. The environment and many different genes interact to determine most psychological traits. 51. Which of the following is NOT true about epigenetics? A. It is a mechanism that turns genes on or off. B. It refers to chemical molecules attached to a gene that "reads" the gene's DNA. C. Its name is derived from the prefix meaning "on or above" the genome. D. Epigenetic changes are hereditary not environmental. Answer: D. Epigenetic changes are hereditary not environmental. 52. Krystal was ill as a baby, and before she was a year old, she was diagnosed with _____________, a genetic defect that causes thick mucus to clog the breathing passages and the digestive system. A. cystic fibrosis B. Down syndrome C. neural tube defect D. Huntington's disease Answer: A. cystic fibrosis 53. When both parents carry an abnormal recessive gene, such as the gene for cystic fibrosis, each of their children has 1 chance in: A. 2 of being a carrier. B. 4 of being a carrier. C. 2 of receiving two abnormal recessive genes. D. 2 of receiving two normal genes. Answer: A. 2 of being a carrier. 54. Baby Shanna has been diagnosed with Tay-Sachs disease. However, neither of her parents has shown symptoms of this disease. What can we conclude from this information? A. Shanna is heterozygous for the Tay-Sachs gene. B. Shanna's parents are homozygous for the Tay-Sachs gene. C. Shanna is homozygous for the Tay-Sachs gene. D. One of Shanna's parents is a carrier of Tay-Sachs, the other is not. Answer: C. Shanna is homozygous for the Tay-Sachs gene. 55. Which birth defect afflicts African Americans more than it does other ethnic groups? A. Tay-Sachs disease B. sickle-cell anemia C. cystic fibrosis D. Cooley's anemia Answer: B. sickle-cell anemia 56. Arnold underwent genetic testing to determine whether he has the gene for Huntington's disease. The test confirmed that he does have it. This is an example of transmission by _____________ inheritance. A. recessive B. dominant C. sex-linked D. multifactorial Answer: B. dominant 57. A pattern of inheritance in which certain characteristics carried on the X chromosome inherited from the mother are transmitted differently to her male and female offspring is called _____________ inheritance. A. recessive B. dominant C. multifactorial D. sex-linked Answer: D. sex-linked 58. Gerald suffers from hemophilia, a blood-clotting disorder. He understands that the gene responsible for this disorder is carried by females but usually affects only males. This is an example of _____________ inheritance. A. heterozygous B. dominant C. sex-linked D. recessive Answer: C. sex-linked 59. Sex-linked traits A. are usually passed from father to son. B. are never manifested in females. C. can be carried by females who do not display them. D. are carried by dominant genes. Answer: C. can be carried by females who do not display them. 60. John has hemophilia, a sex-linked, blood-clotting disorder transmitted by a recessive gene. Neither his mother nor his father has symptoms of this disease. What can we conclude about the genetic makeup of John's parents? A. Both of his parents have the faulty gene. B. The mother is a carrier of hemophilia, but the father does not have the gene. C. The mother is homozygous for the faulty gene, whereas the father is heterozygous. D. The father has the faulty gene, whereas the mother does not. Answer: B. The mother is a carrier of hemophilia, but the father does not have the gene. 61. Klinefelter syndrome and Turner syndrome are caused by abnormalities of the A. autosomes. B. sex chromosomes. C. teratogens. D. phenotypes. Answer: B. sex chromosomes. 62. A chromosomal disorder characterized by moderate-to-severe mental retardation and a downward-sloping skin fold at the inner corners of the eyes is called A. cystic fibrosis. B. Tay-Sachs disease. C. Down syndrome. D. sickle-cell anemia. Answer: C. Down syndrome. 63. Which of the following statements regarding Down syndrome is FALSE? A. The vast majority of genetic abnormalities are associated with the mother's ovum. B. There is no connection to paternal genetic abnormalities. C. Down syndrome is also called trisomy-21. D. The risk of having a child with Down syndrome increases with parental age. Answer: B. There is no connection to paternal genetic abnormalities. 64. Which of the following is NOT the responsibility of a genetic counselor? A. Taking a family history of prospective parents B. Making clients aware of the statistical probabilities of certain genetic conditions C. Presenting options of alternative courses of action D. Advising clients on which course of action to take Answer: D. Advising clients on which course of action to take 65. A karyotype is a(n) A. abnormal genotype. B. abnormal phenotype. C. photographic chart of chromosomal abnormalities. D. test of developing fetal cells. Answer: C. photographic chart of chromosomal abnormalities. 66. The misconception that individuals with a specific gene are destined to inherit that disease is called A. gene mapping. B. human genome. C. genetic engineering. D. genetic determinism. Answer: D. genetic determinism. 67. It eventually may be possible to treat inherited diseases by repairing or replacing abnormal genes through A. genetic counseling. B. gene therapy. C. genome replication. D. phoneme therapy. Answer: B. gene therapy. 68. Brynn carries the gene for heart disease. She now believes that no matter what steps she takes to protect her health, she will have a heart attack in the future. Brynn's misconception is known as A. genetic variability. B. genetic determinism. C. biological destiny. D. a false positive. Answer: B. genetic determinism. 69. The quantitative study of relative hereditary and environmental influences on behavior is called A. genetic testing. B. qualitative genetic research. C. cognitive genetics. D. behavioral genetics. Answer: D. behavioral genetics. 70. A statistical estimate of how much heredity influences individual differences in a specific trait at a certain time within a given population is referred to as A. inheritance. B. heritability. C. heredity. D. genetics. Answer: B. heritability. 71. In attempting to study the degree to which genetics influences activity levels in newborns, a researcher compares monozygotic and dizygotic twins for their level of similarity on that trait. This research is attempting to determine the _____________ of the trait activity levels. A. phenotype B. genotype C. karyotype D. heritability Answer: D. heritability 72. Doug has been recruited for a family study looking at the heritability of personality traits. Who else will most likely be included in the study? A. Doug's brother or sister B. Doug's spouse C. Doug's closest friends D. Doug's first cousins Answer: A. Doug's brother or sister 73. Although Roberto's adoptive parents are short in stature, he is growing to be tall like his biological mother. What might we conclude about Roberto's height? A. It is influenced primarily by environmental factors. B. It is influenced primarily by hereditary factors. C. Nutrition did not contribute to his height. D. It is primarily a result of independent segregation. Answer: B. It is influenced primarily by hereditary factors. 74. Which of the following most clearly demonstrates the influence of environment? A. Georgio, who was adopted at birth, and died at the same age as his biological father did B. Sally, who was adopted at the age of 2, and walks like her adoptive mother C. Bill and Jim, identical twins who were separated at birth, and are both overweight D. Ann and Jennie, fraternal twins who were reared apart, only Ann has high blood pressure Answer: B. Sally, who was adopted at the age of 2, and walks like her adoptive mother 75. Susan and Betty are monozygotic twins, whereas Ming and Li are dizygotic twins. If a particular trait is determined primarily by hereditary factors, what would be the relative degree of concordance in these two twin pairs? A. Ming and Li are more concordant than are Susan and Betty. B. Susan and Betty are more concordant than are Ming and Li. C. Given similar environments, the two sets of twins are equally concordant. D. It is not possible to determine concordance from studying twins. Answer: B. Susan and Betty are more concordant than are Ming and Li. 76. Scientists generally accept that A. human development is determined almost entirely by heredity. B. human development is determined almost entirely by environment. C. heredity and environment constantly interact to shape human development. D. hereditary and environmental influences on human development are impossible to identify. Answer: C. heredity and environment constantly interact to shape human development. 77. Which of the following statements about the influences of heredity and environment is correct? A. A person's height is determined by his or her genes. B. A person's potential range of height is genetically determined, but actual height may be influenced by nutrition. C. The genetic upper limit or range of height can be increased by improved nutrition. D. Nutrition is more important than are genetic limits or range. Answer: B. A person's potential range of height is genetically determined, but actual height may be influenced by nutrition. 78. Depending on environmental conditions, the potential variability in the expression of a hereditary trait is called A. canalization. B. genetics. C. reaction range. D. environmental interaction. Answer: C. reaction range. 79. Which child is likely to exhibit the smallest reaction range for the trait of intelligence? A. A child born with severe brain damage B. A child born to parents with low intelligence C. A child born to parents with normal intelligence D. A child born to parents with extremely high intelligence Answer: A. A child born with severe brain damage 80. Despite many variations in environmental conditions and rearing practices, most children learn to walk at about the same time and in the same sequence. We would say that walking is a _____________ trait. A. recessive B. dominant C. monozygotic D. canalized. Answer: D. canalized. 81. Traits that exhibit a _____________ degree of canalization will have a _____________ reaction range. A. low; narrow B. high; wide C. high; narrow D. low; nonexistent Answer: C. high; narrow 82. A strongly canalized trait is one that A. is easily influenced by environmental conditions. B. is affected little by environmental conditions. C. appears only in certain situations. D. has a large reaction range. Answer: B. is affected little by environmental conditions. 83. The effects of similar environmental conditions on genetically different individuals is called A. reaction range. B. genotype-environment interaction. C. canalization D. niche-picking. Answer: B. genotype-environment interaction. 84. The environment often reflects or reinforces genetic differences. In other words, certain genetic and environmental influences tend to reinforce each other. This tendency is called A. environment-genotype covariance. B. genotype-environment correlation. C. niche-picking. D. shared environmental effects. Answer: B. genotype-environment correlation. 85. William came from a disadvantaged background, with abusive parents. In high school, he turned his exceptional ability to win arguments into a positive characteristic by participating on the school debate team. When the debate team visited the nation's capital, William was so inspired by what he saw there that he decided to pursue a career in government. Which of the following terms best explains William's development? A. Genotype-environment interaction B. Canalization C. Reaction range D. Shared environmental effects Answer: A. Genotype-environment interaction 86. In college, Cathy tried a number of different majors until she found one that was right for her. She was originally interested in a career in research and was very successful academically. She later decided that she missed social interaction, so she decided to try teaching high school biology. The first time that she stood in front of the classroom, she knew that this was where she belonged. Which of the following terms best explains Cathy's development? A. Passive genotype-environment correlation B. Accommodating genotype-environment correlation C. Evocative genotype-environment correlation D. Active (niche-picking) genotype-environment correlation Answer: D. Active (niche-picking) genotype-environment correlation 87. The idea that each child in a family grows up in a unique environment is referred to as _____________ effects. A. nonshared environmental B. macrosystem C. shared environmental D. hereditary Answer: A. nonshared environmental 88. Although brothers Jono and Roman bear a striking physical resemblance to each other, they differ greatly in intelligence and personality. One reason for this difference may be A. normative events. B. age-graded normative events. C. nonshared environmental effects. D. shared environmental effects. Answer: C. nonshared environmental effects. 89. Which of the following statements about environmental influences is FALSE? A. Children growing up in the same family experience the same environment. B. Some individual experiences, such as illness and injury, become environmental influences. C. Siblings are usually more different than they are alike. D. The home is the primary environment in the early years of life. Answer: A. Children growing up in the same family experience the same environment. 90. Which of the following statements regarding obesity is FALSE? A. Twin studies indicate that 40-70% of the risk of obesity is genetic. B. Twin studies indicate that up to 80% of the risk of obesity is environmental. C. Obesity is on the rise in western countries. D. A predisposition toward obesity does not necessarily mean that a person will become obese. Answer: B. Twin studies indicate that up to 80% of the risk of obesity is environmental. 91. Intelligence is a trait that is A. polygenetic. B. determined by a relatively small number of recessive genes. C. the karyotype of both parents. D. the phenotype of both parents. Answer: A. polygenetic. 92. More complex traits, such as intelligence, seem to be the result of A. heredity, or nature. B. the environment, or nurture. C. an interaction between nature and nurture. D. maturation. Answer: C. an interaction between nature and nurture. 93. Data on the heritability of intelligence indicates that when two people are very closely related, their A. similarity in intelligence is low. B. intelligence test scores are much more similar than are those of unrelated people. C. intelligence test scores are similar only if they have been reared together. D. intelligence test scores are no more similar than would be expected for any two randomly selected individuals. Answer: B. intelligence test scores are much more similar than are those of unrelated people. 94. Sophia was adopted when she was 1. If she is given an intelligence test at age 16, her intelligence level is likely to be more similar to that of her A. adoptive mother. B. adoptive father. C. biological mother. D. maternal grandparents. Answer: C. biological mother. 95. Which of the following statements about heredity and personality traits is correct? A. Most personality traits seem to be inherited and unalterably imprinted at birth. B. Although many personality traits seem to be inherited, they are not unalterably imprinted at birth. C. Personality traits, unlike many physical traits, do not seem to be inherited. D. Because of the limitations of research methodology, researchers have not been able to identify any personality traits that are genetically based. Answer: B. Although many personality traits seem to be inherited, they are not unalterably imprinted at birth. 96. Temperament seems largely determined by A. the age of your parents when you were conceived. B. the number of siblings you have. C. your genotype. D. your karyotype. Answer: C. your genotype. 97. A psychological disorder that is marked by a loss of contact with reality, includes such symptoms as hallucinations and delusions, and seems to have a strong genetic component is A. neuroticism. B. depression. C. schizophrenia. D. mental retardation. Answer: C. schizophrenia. 98. Many studies suggest that schizophrenia A. has a strong genetic component. B. has a strong environmental component. C. is a result of environmental stress. D. is caused by a single gene. Answer: A. has a strong genetic component. 99. Several members of the Theroz family suffer from schizophrenia. Concordance rates for schizophrenia are highest between: A. mothers and biological sons or daughters. B. grandparents and grandchildren. C. members of monozygotic twin pairs. D. members of dizygotic twin pairs. Answer: C. members of monozygotic twin pairs. 100. A cause of schizophrenia may be A. advanced paternal age. B. the mother's loss of a close relative in the first trimester of pregnancy. C. maternal rubella infection during pregnancy. D. all of the above. Answer: D. all of the above. Essay Questions 101. Describe how and when human conception normally occurs. In your answer, include the following terms: fertilization, gamete, ovulation, and zygote. Answer: Human conception typically occurs when a sperm cell (male gamete) fertilizes an egg cell (female gamete) during ovulation. Ovulation is the release of a mature egg from the ovary, usually around the middle of the menstrual cycle. Fertilization takes place in the fallopian tube, where the sperm penetrates the egg, forming a zygote. The zygote then undergoes rapid cell division, beginning the process of embryonic development. 102. Define what scientists mean by the term infertility. List the causes of infertility for both males and females, and describe three alternate ways that couples can become pregnant. Answer: Infertility refers to the inability to conceive after one year of regular unprotected sexual intercourse. Causes for males include low sperm count, sperm abnormalities, and hormonal imbalances. Causes for females include ovulation disorders, blocked fallopian tubes, and uterine abnormalities. Alternatives for conception include assisted reproductive technologies like in vitro fertilization (IVF), intrauterine insemination (IUI), and fertility medications to stimulate ovulation. 103. The study of inherited factors that affect development is referred to as heredity. Define the function of each of the following terms, and explain their relationship to the mechanisms of heredity: DNA, chromosomes, and genes. Answer: DNA (Deoxyribonucleic acid) serves as the genetic blueprint, encoding instructions for the development, functioning, and growth of all living organisms. Chromosomes are structures within cells that contain DNA, organizing and packaging genetic information into manageable units. Genes are segments of DNA that carry specific instructions for traits, such as eye color or height, and are passed down from parents to offspring through heredity. Together, these components form the molecular basis of inheritance and determine an individual's genetic makeup. 104. Using the following terms, describe the factors involved in dominant and recessive inheritance: alleles, homozygous, heterozygous, genotype, and phenotype. Answer: Alleles are alternate forms of a gene, with dominant alleles exerting their effects over recessive alleles. Homozygous individuals have two identical alleles for a particular gene (either both dominant or both recessive), while heterozygous individuals possess two different alleles (one dominant and one recessive). Genotype refers to an individual's genetic makeup (e.g., BB, Bb, or bb), whereas phenotype is the observable expression of that genotype (e.g., brown eyes if dominant, blue eyes if recessive). 105. Define multifactorial transmission. Provide several examples of how multifactorial transmission plays a role in the expression of most traits. Answer: Multifactorial transmission refers to the interaction of multiple genetic and environmental factors in influencing the expression of traits. Examples include height, which is influenced by both genetic factors (multiple genes contribute) and environmental factors (nutrition, health). Risk for diseases like diabetes or heart disease also involves a complex interplay of genetic predisposition and lifestyle factors such as diet and exercise habits. 106. When a couple decides to conceive a baby, one of their greatest concerns is that the baby be healthy. Describe at least three birth defects described in your textbook, and explain how each of them is transmitted. For each problem, describe possible treatment options. Answer: Three birth defects include: 1. Down syndrome: Caused by an extra copy of chromosome 21 (trisomy 21), usually due to nondisjunction during meiosis. Treatment involves early intervention programs, special education, and medical management for associated health issues. 2. Cleft lip and palate: Can be caused by genetic factors or environmental influences. Treatment includes surgical repair shortly after birth, followed by speech therapy and orthodontic care as needed. 3. Spina bifida: Results from incomplete closing of the neural tube during fetal development, influenced by genetic and environmental factors. Treatment involves surgical correction shortly after birth to prevent complications and ongoing management of associated health issues like mobility impairments and bladder problems. 107. Many birth defects are transmitted by dominant or recessive genes. Others are transmitted by sex-linked inheritance. Define the terms dominant, recessive, and sex-linked genes. Give an example of each, and describe a defect transmitted in each of these three ways. Answer: Dominant gene: A gene that, when present, masks the expression of the corresponding recessive allele. Example: Huntington's disease, where inheriting one dominant allele leads to the disorder. Recessive gene: A gene that is expressed only in the absence of a dominant allele. Example: Cystic fibrosis, where inheriting two recessive alleles (one from each parent) results in the condition. Sex-linked gene: A gene located on a sex chromosome (usually the X chromosome) and thus shows different patterns of inheritance in males and females. Example: Hemophilia, a disorder where the gene for clotting factors is carried on the X chromosome, causing bleeding disorders predominantly in males who inherit the recessive allele. 108. What is Down syndrome? Explain how often it occurs. Who is at risk of giving birth to a child with this disorder? What challenges does an individual with Down syndrome face? Answer: Down syndrome is a genetic disorder caused by the presence of an extra copy of chromosome 21 (trisomy 21). It occurs in about 1 in every 700 births worldwide. Advanced maternal age increases the risk, though most babies with Down syndrome are born to younger mothers due to higher fertility rates in younger women. Individuals with Down syndrome may face developmental delays, intellectual disability, and increased risk of certain health conditions like heart defects and leukemia. 109. Give five examples of the influences of heredity and environment on a preschool-age child. Answer: 1. Physical traits: Hereditary factors influence traits like eye color and hair texture, while nutrition and healthcare in the environment impact physical growth. 2. Language development: Genetic predispositions may affect language abilities, but exposure to language-rich environments at home and in preschool settings also plays a crucial role. 3. Personality traits: Temperament and personality tendencies can be influenced by genetics, but parenting styles and social interactions in the environment shape behavior. 4. Cognitive skills: Genetic factors contribute to cognitive abilities, but educational opportunities and stimulating experiences in the environment support cognitive development. 5. Health outcomes: Genetic factors influence susceptibility to certain health conditions, but access to healthcare, nutrition, and exposure to environmental toxins also impact overall health in preschool-age children. 110. Describe the role of heredity and environment in obesity, schizophrenia, autism, and intelligence. Answer: 1. Obesity: Hereditary factors can predispose individuals to obesity, influencing metabolism and fat storage. Environmental factors such as diet and physical activity levels also play significant roles. 2. Schizophrenia: Genetic factors contribute to susceptibility, with multiple genes involved. Environmental factors like stress, prenatal infections, and substance abuse can trigger the disorder in genetically predisposed individuals. 3. Autism: Hereditary factors are strongly implicated, with genetic mutations and variations influencing brain development. Environmental factors such as prenatal exposure to toxins and parental age at conception also play roles. 4. Intelligence: Both hereditary and environmental factors influence intelligence. Genetic variations contribute to cognitive abilities, while environmental factors such as education, nutrition, and stimulating experiences also impact intellectual development. True/False Questions 111. A one-celled organism that results from fertility is called a blastocyst. Answer: False 112. Sex cells are also called gametes. Answer: True 113. At birth, girls are born with all of the ova she will ever produce. Answer: True 114. The most common cause of infertility is a woman's failure to produce ova. Answer: False 115. Dizygotic twins are the result of two ova and two sperm. Answer: True 116. A typically developing person has 23 pairs of chromosomes for a total of 46. Answer: True 117. The Y in an XY pattern comes from the father. Answer: True 118. Gregor Mendel is credited with laying the foundation for our understanding of genetic inheritance. Answer: True 119. Mai has brown eyes and her partner Jonas has blue eyes. Their offspring will be homozygotic for the trait eye color. Answer: False 120. Waylon is tall and his partner Tara is short. Their child will be heterozygotic for the trait height. Answer: True 121. Most traits, like intelligence, are polygenic. Answer: True 122. Research suggests that being light skinned is the result of a minute genetic mutation that occurred tens of thousands of years ago. Answer: True 123. All of your genetic material is your genotype, whereas your observed characteristics are your phenotype. Answer: True 124. Luz has brown hair, brown eyes, and is generally considered smart and funny by others. This is an example of her genotype. Answer: False 125. The bidirectional interplay of all activity of genetic and environmental levels is considered to be your genotype. Answer: False 126. The differential expression of certain genetic traits based on if the trait came from the mother or the father is called epigenesis. Answer: False 127. Babies that are born with only Y chromosomes and no X chromosomes are not viable. But babies with at least one X are. Answer: True 128. Sex-linked characteristics generally come from the father. Answer: False 129. Down syndrome occurs on the thirteenth chromosome. Answer: False 130. If a trait like intelligence has a heritability estimate of 0.86 it would indicate that there is a weak genetic influence on intelligence and that environment is far more important. Answer: False 131. The home you grow up in, your parents' SES level, and the friends your parents choose for you to play with are all examples of a passive-genotype effect. Answer: True Test Bank for A Child's World: Infancy Through Adolescence Diane E. Papalia, Gabriela Martorell, Ruth Duskin Feldman 9780078035432
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