3 Portage Learning BIOD 151 Module 3 Exam Study Guide
Brand New Questions A++ (2022-2023)
Organic Chemistry I (University of Nairobi)
Portage Learning BIOD 151 Module 3 Exam Study Guide w/
Brand New Questions A++ (2022-2023)
M3: Exam- Requires Respondus Lock Down Browser
Question 1
Explain why someone who has hypergastrinemia (excessive secretion of gastrin) might develop
gastric/stomach ulcers.
Answer: Gastrin stimulates the secretaion of pepsinogenes and HCL. If it is excess amounr that
means it would be lead to erosion of the stomach.
Rationale:
Gastrin stimulates the secretions of pepsinogens and hydrochloric acid. Excess amounts would
lead to erosion of the stomach lining.
Question 2
Explain in detail how the stomach contents enter the small intestine.
Answer: There is the pyloric sphincter at the base of stomach. Therefore, this valve relaxes
causing a small quantity of chyme to pass the opening into the first part of small intestine. And
then, this initiates a reflex. That is why the muscles of the sphincter to contrcat and close the
opening temporarily. After sphincter relaxes again and it allows more chyme to enter.
Rationale:
The pyloric sphincter (valve), located at the base of the stomach, relaxes causing a small quantity
of chyme to pass through the opening into the first part of the small intestine.
This initiates a reflex that causes the muscles of the sphincter to contract and close the opening
temporarily. Then the sphincter relaxes again and allows more chyme to enter.
Question 3
Look carefully at the diagram below. Label the following 5 organs of the digestive system. To
receive credit for the intestines you must label the specific region.
3: __________
4: __________
7: __________
9: __________
10: __________
Answer:
3: Stomach
4: Gallbladder
7: Jejunum
9: Appendix
10: Rectum
Rationale:
3: Stomach
4: Gallbladder
7: Jejunum (not small intestine)
9: Appendix (not large intestine)
10: Rectum (not large intestine)
Question 4
A patient is experiencing vitamin toxicity. What type of vitamin would be causing this toxicity?
Explain your answer.
A. Water soluble vitamin
B. Fat soluble vitamin
C. All of the above
Answer:
Fat soluble vitamin. These vitamins are stored within the body's fat stores making it harder for
the body to rid itself of them. Therefore it can cause vitamin toxicity.
B. Fat soluble vitamin.
Rationale:
Fat soluble vitamins are stored within the body’s fat stores making it harder for the body to rid
itself of them.
Question 5
Explain which digestive system functions are carried out by the large intestine.
Answer:
Absorption: Water and electrolytes are reabsorbed and vitamins are absorbed. Defecation ; Feces
goes to the rectum then excreted va anus.
Rationale:
Absorption: In the large intestine water and electrolytes are reabsorbed and vitamins are
absorbed.
Defecation: Feces travel to the rectum where it is excreted via the anus.
Question 6
Note: Essay answers must clearly be in your own words. Answer the following essay
question:
Describe parietal cells and chief cells: name their location, secretions and purposes.
Answer:
Parietal cells located in the wall of stomach body secrete HCL acid, generate a pH of 1.3-3.5.
This acidite kills many bacteria. Also, the low pH stops the activity of salivary amylase.
Secretion of HCL acis is essential in the activate of pepsin.
Chief cells produces pepsinogen. Pepsinogen is secreted by the chief cells in the stomach. HCL
acid converts the inactive pepsinogen into the active enzyme pepsin and then it begins
breakdown of proteins.
Rationale:
The parietal cells (located in the wall of the stomach body) secrete hydrochloric acid, generating
a pH of 1.3-3.5. This very acidic pH kills many of the bacteria ingested along with food. In
addition, the low pH stops the activity of salivary amylase. The secretion of hydrochloric acid is
essential in the activation of pepsin.
Chief cells: secrete pepsinogen. Pepsinogen (a pre-enzyme) is secreted by the chief cells in the
stomach. Hydrochloric acid converts the inactive pepsinogen (secreted by the chief cells) into the
active enzyme pepsin which begins the breakdown of proteins.
Question 7
Match the digestive organ with the one substance it produces:
Other Incorrect Match Options:
• Bile
• Salivary amylase
• Trypsin
Question 8
What is the purpose of the hormone Leptin?
a. Increase hunger, decrease satiety
b. Increase hunger, increase satiety
c. Decrease hunger, increase satiety
d. Decrease hunger, decrease satiety
Answer: c. Decrease hunger, increase satiety
Rationale:
Leptin decreases hunger and increases satiety by signaling to the brain that fat stores are
sufficient.
Question 9
Which of the following statements is false?
a. Taste buds are located on the surface of the mouth and the wall of the pharynx.
b. The ileocecal valve controls the entrance of chyme into to the small intestine. (It controls the
entrance to the large intestine)
c. The gall bladder, teeth, and tongue are considered accessory organs to the digestive system.
d. The alimentary canal is a continuous muscular tube, open at both ends.
Answer: b. The ileocecal valve controls the entrance of chyme into to the small intestine.
Rationale:
The ileocecal valve actually controls the entrance of chyme from the small intestine into the large
intestine (colon), not the other way around. The valve prevents the backflow of colonic contents
into the small intestine.
Question 10
True/False:
Lipids can be divided into three categories: saturated fat, unsaturated fat, and cholesterol.
a. True
b. False
Answer: b. False
Rationale:
While saturated fats, unsaturated fats, and cholesterol are important components of lipids, they
do not represent the full range of lipid categories. Lipids can be divided into broader categories,
including:
1. Triglycerides (which include both saturated and unsaturated fats, and make up the majority of
dietary fats).
2. Phospholipids (which are key components of cell membranes).
3. Steroids (which include cholesterol and hormones like estrogen and testosterone).
4. Waxes (which are used for protection and waterproofing in plants and animals).
Thus, limiting lipid categories to just saturated fat, unsaturated fat, and cholesterol is too narrow.
Question 11
Anabolism combines smaller molecules to make larger molecules.
a. True
b. False
Answer: a. True
Rationale:
Anabolism is a metabolic process that involves the synthesis of larger molecules from smaller
ones. It is a constructive process where simple molecules are built up into complex molecules,
such as proteins from amino acids, and glycogen from glucose. This process typically requires
energy input.
Question 12
The oropharynx is the most superior region of the pharynx.
a. True
b. False (The nasopharynx is the most superior region)
Answer: b. False
Rationale:
The pharynx is divided into three regions:
1. Nasopharynx (most superior, located behind the nasal cavity)
2. Oropharynx (middle region, located behind the oral cavity)
3. Laryngopharynx (most inferior, located near the larynx)
Therefore, the nasopharynx is the most superior region of the pharynx, not the oropharynx.
Question 13
The pharynx has two types of skeletal muscle: circumferential and oblique.
a. True
b. False (It does not include an oblique layer)
Answer: b. False
Rationale:
The pharynx has two types of skeletal muscle layers:
1. Circular (or circumferential) muscles: These muscles are arranged in a circular fashion and
help constrict the pharynx during swallowing.
2. Longitudinal muscles: These muscles run vertically and help elevate the pharynx and larynx
during swallowing.
There is no oblique muscle layer in the pharynx.
Question 14
The digestive work of salivary amylase is an example of mechanical digestion.
a. True
b. False (Chemical digestion)
Answer: b. False
Rationale:
Salivary amylase is an enzyme found in saliva that breaks down starches into simpler sugars.
This process is an example of chemical digestion, not mechanical digestion.
• Mechanical digestion refers to the physical breakdown of food into smaller pieces (e.g.,
chewing).
• Chemical digestion involves enzymatic processes that chemically alter food components (e.g.,
salivary amylase breaking down starches).
Question 15
Label the following three types of raised bumps on the tongue. Describe the purpose of type C.
A: ___________
B: ___________
C: ___________
Describe C:
Answer:
A. Filiform papillae
B: Circumvallete papillae
C; Fungiform Papillae
C: They are raised bumps and located on the tounge. Fungiform papillae contain taste buds.
There type of papillae help to grip food on the tounge.
Rationale:
A: Filiform papillae
B: Circumvallate papillae
C: Fungiform papillae
Describe C: The papillae are raised bumps on the tongue. The three types of papillae help to grip
food on the tongue: circumvallate, fungiform and filiform. Fungiform papillae contain taste buds.
Question 16
Which of the following statements is true concerning glycolysis?
a. Pyruvic acid are broken down into glucose.
b. Two ATP molecules are formed in first breakdown of glucose.
c. Glucose is broken down into three pyruvate molecules.
d. Glucose is broken down into two sucrose molecules.
Answer: b. Two ATP molecules are formed in first breakdown of glucose.
Rationale:
This statement is incorrect. Glycolysis initially requires two ATP molecules (investment phase)
to phosphorylate glucose and its intermediates, but it generates four ATP molecules in the later
stages (payoff phase). The net gain is two ATP molecules.
Question 17
Which of the following statements is false concerning the second stage of glucose breakdown?
a. This second stage is also known as the TCA cycle.
b. Pyruvic acid is converted to carbon dioxide.
c. Additional ATP is formed.
d. This is also known as the electron transport system.
Answer: d. This is also known as the electron transport system.
Rationale:
This statement is false. The electron transport system (or chain) is actually the third stage of
glucose breakdown, not the second. It follows the TCA cycle and is responsible for producing
the majority of ATP through oxidative phosphorylation.
Question 18
Which of the following statements is false concerning the Electron Transport System?
a. Anaerobic respiration is more efficient than aerobic respiration.
b. Approximately a total of 34 ATP are formed.
c. Protons are pumped out of the inner mitochondrial membrane.
d. The proton motive force forms ATP molecules.
Answer: a. Anaerobic respiration is more efficient than aerobic respiration.
Rationale:
This statement is false. Aerobic respiration is more efficient than anaerobic respiration. In
aerobic respiration, which occurs in the presence of oxygen, up to 34-36 ATP molecules can be
generated per glucose molecule. In contrast, anaerobic respiration (such as fermentation)
produces only 2 ATP molecules per glucose molecule.
Question 19
Label the diagram below, including left or right. Describe tooth (A).
A: ____________
C: ____________
E: ____________
F: ____________
Describe tooth type A:
Answer:
A: Left Central Incisor
C: Left Canine
E: Right Molar
F: Maxilla (Hard Palate )
A: Left Central Incisor; It is Chisel-shaped for biting food.
Rationale:
A: Left Central Incisor
C: Left Canine (cuspid)
E: Right Molar
F: Maxilla (Hard Palate)
Describe tooth type A:Chisel-shaped for biting food
Question 20
Match the structure with the best description:
Pancreas:
a. Storage site for bile
b. Attached to the soft palate
c. Secretes juices which digest all types of foods
d. Stores glycogen and produces urea
e. Forms food into a bolus
Answer: c. Secretes juices which digest all types of foods
Rationale:
The pancreas produces pancreatic juices that contain a variety of digestive enzymes, including
amylase (for carbohydrates), proteases (for proteins), and lipase (for fats). These enzymes help in
digesting all types of nutrients in the small intestine.
Question 21
Small Intestine:
a. First section is called the jejunum
b. Contains the LES
c. Attaches to the greater omentum
d. Pancreas secretions enter here via Hepatopancreatic ampulla
e. Secretes Vitamin K
Answer: d. Pancreas secretions enter here via Hepatopancreatic ampulla
Rationale:
In the small intestine, pancreatic secretions enter the duodenum (the first section of the small
intestine) via the hepatopancreatic ampulla (ampulla of Vater). This ampulla is the junction
where the common bile duct and the pancreatic duct merge before releasing their contents into
the duodenum.
Question 22
Muscularis externa (layer of tissue):
a. Made of two layers of muscle
b. Innermost layer
c. Secretes mucous
d. Contains blood and lymph vessels
e. Begins in the mouth
Answer: b. Made of two layers of muscle
Rationale:
The muscularis externa is a layer of the digestive tract composed of two layers of muscle:
1. Inner circular layer: This layer helps in constricting the lumen of the digestive tract.
2. Outer longitudinal layer: This layer helps in shortening the length of the digestive tract.
Together, these muscle layers facilitate peristalsis and segmentation movements within the
digestive tract. The muscularis externa is not the innermost layer (which is the mucosa), does not
secrete mucus, does not primarily contain blood and lymph vessels (those are found in the
submucosa), and it does not specifically begin in the mouth.
Question 23
Dentin:
a. Upper portion of gums
b. Outermost layer
c. Bone-like substance
d. Hard connective tissue
e. Contains longitudinal muscle
Answer: d. Bone-like substance
Rationale:
Dentin is a dense, bone-like tissue found beneath the enamel and cementum of the tooth. It forms
the bulk of the tooth and supports the enamel. It is not the outermost layer (which is enamel), and
it does not contain longitudinal muscle. Dentin is not classified as a connective tissue but has a
composition and hardness similar to bone.
Question 24
Common Bile Duct
a. Contains secretions from the pancreas
b. Joins with the pancreatic duct
c. Enters the jejunum
d. Contains secretions from the salivary glands
e. Contains lymph vessels and nerves
Answer: b. Joins with the pancreatic duct
Rationale:
The common bile duct joins with the pancreatic duct at the hepatopancreatic ampulla (ampulla of
Vater). This junction allows bile from the gallbladder and liver and pancreatic secretions from the
pancreas to mix and enter the duodenum together. This combined secretion aids in digestion and
the emulsification of fats in the small intestine.
