In a low-carbohydrate diet, most of the calories are supplied by:
- A. proteins.
- B. fats.
- C. carbohydrates.
- D. vitamins.
Correct Answer: B
Rationale: In a low-carbohydrate diet, fats become the primary source of calories as carbohydrate intake is restricted. Proteins can contribute to caloric intake but are not the primary source in a low-carbohydrate diet. Carbohydrates are intentionally limited in this diet, so they do not supply most of the calories. Vitamins are essential nutrients but do not provide calories.
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Cholecystokinin (CCK) is produced in the:
- A. duodenum.
- B. stomach.
- C. pancreas.
- D. liver.
Correct Answer: A
Rationale: Cholecystokinin (CCK) is produced in the duodenum, not the stomach, pancreas, or liver. It is released in response to the presence of food in the duodenum, where it plays a crucial role in regulating digestive processes by stimulating the release of bile from the gallbladder and enzymes from the pancreas. Therefore, the correct answer is the duodenum (Choice A). Choices B, C, and D are incorrect because CCK is not produced in the stomach, pancreas, or liver.
What is the primary nutritional function of the large intestine?
- A. Absorption of fats.
- B. Excretion of waste products.
- C. Excretion of bacteria.
- D. Absorption of water.
Correct Answer: D
Rationale: The correct answer is D: Absorption of water. The primary nutritional function of the large intestine is to absorb water from the indigestible food residue that enters it from the small intestine. This absorption of water helps to form solid waste, which is then eliminated from the body. Choices A, B, and C are incorrect because the large intestine is not primarily responsible for the absorption of fats, excretion of waste products, or excretion of bacteria. While the large intestine does play a role in waste elimination and contains bacteria beneficial for digestion, its main function in terms of nutrition is the absorption of water.
Which of the following is a source of complete protein?
- A. Cereal grains.
- B. Beans.
- C. Nuts.
- D. Eggs.
Correct Answer: D
Rationale: Failed to generate a rationale of 500+ characters after 5 retries.
At what pH does the digestion of protein by pepsin in the stomach require?
- A. 1.8 and 3.5.
- B. 4.8 and 7.0.
- C. 6.8 and 8.5.
- D. 7.8 and 10.0.
Correct Answer: A
Rationale: The correct answer is A: 1.8 and 3.5. Pepsin, an enzyme involved in protein digestion, functions optimally in an acidic environment, specifically between pH 1.8 and 3.5. This low pH is necessary for pepsin to break down proteins effectively. Choices B, C, and D are incorrect because pepsin requires a highly acidic environment, ruling out the pH ranges listed in those options.
Which hormone prevents excessive gastric activity?
- A. Gastrin
- B. Enterogastrone
- C. Secretin
- D. Cholecystokinin
Correct Answer: B
Rationale: The correct answer is Enterogastrone. Enterogastrone is a hormone that inhibits excessive gastric activity by slowing down stomach contractions and emptying. Gastrin (choice A) stimulates gastric acid secretion, secretin (choice C) regulates pH levels in the duodenum, and cholecystokinin (choice D) stimulates the release of digestive enzymes and bile.