How many different amino acids make up human proteins?
- A. 9
- B. 13
- C. 15
- D. 20
Correct Answer: D
Rationale: The correct answer is D: 20. There are 20 different amino acids that combine to form proteins in the human body. Each amino acid has a unique side chain that determines its properties. Choices A, B, and C are incorrect as they do not represent the total number of different amino acids found in human proteins.
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What are the small, fingerlike projections into the intestinal lumen called?
- A. Villi
- B. Goblets
- C. Lacteals
- D. Polyps
Correct Answer: A
Rationale: The correct answer is A: Villi. Villi are small fingerlike projections in the intestine that increase the surface area for nutrient absorption. Goblets (choice B) are mucus-secreting cells in the intestines. Lacteals (choice C) are lymphatic vessels in the small intestine that absorb dietary fats. Polyps (choice D) are abnormal tissue growths.
The interrelated network of nerves within the gastrointestinal wall that regulates its muscular action is known as the:
- A. gastric nerve plexus.
- B. biliary nerve plexus.
- C. intramural nerve plexus.
- D. intestinal nerve plexus.
Correct Answer: C
Rationale: The correct answer is C - intramural nerve plexus. This network of nerves regulates the muscular movements within the gastrointestinal wall. The gastric nerve plexus (choice A) specifically relates to the stomach, not the entire gastrointestinal tract. The biliary nerve plexus (choice B) is associated with the bile ducts and gallbladder, not the regulation of muscular action. The intestinal nerve plexus (choice D) is a general term that doesn't specifically refer to the network of nerves within the gastrointestinal wall.
What is the term for the production of glucose from protein, lactate, or glycerol?
- A. glycolysis
- B. gluconeogenesis
- C. glycogenolysis
- D. glucogenesis
Correct Answer: B
Rationale: Gluconeogenesis is the correct term for the production of glucose from non-carbohydrate sources such as protein, lactate, or glycerol. Choice A, glycolysis, is the process of breaking down glucose into pyruvate. Choice C, glycogenolysis, is the breakdown of glycogen into glucose. Choice D, glucogenesis, is not a recognized term in biochemistry.
Which hormone stimulates the gallbladder to contract?
- A. Secretin.
- B. Cholecystokinin (CCK).
- C. Gastrin.
- D. Gastric inhibitory polypeptide (GIP).
Correct Answer: B
Rationale: Cholecystokinin (CCK) is the hormone responsible for stimulating the gallbladder to contract and release bile into the small intestine. Secretin primarily acts on the pancreas to stimulate the secretion of bicarbonate-rich fluid. Gastrin functions in the stimulation of gastric acid secretion, while Gastric inhibitory polypeptide (GIP) plays a role in inhibiting gastric acid secretion and stimulating insulin release.
What is a major function of glucose?
- A. Produce energy.
- B. Transport oxygen to cells.
- C. Convert fat to glycogen.
- D. Maintain body weight.
Correct Answer: A
Rationale: Glucose serves as a primary source of energy for the body, especially for the brain and muscles. Choice B is incorrect because glucose itself is not responsible for transporting oxygen to cells. Choice C is incorrect as glucose is converted to glycogen, not the other way around. Choice D is incorrect as glucose itself does not play a direct role in maintaining body weight.