What substance acts as an emulsifier and helps absorb digested fat?
- A. bile
- B. trypsin
- C. lipase
- D. cholecystokinin (CCK)
Correct Answer: A
Rationale: The correct answer is A: bile. Bile acts as an emulsifier, breaking down fats into smaller droplets to aid in digestion and absorption. Trypsin is a digestive enzyme that acts on proteins, not fats. Lipase is an enzyme that breaks down fats, but it doesn't act as an emulsifier. Cholecystokinin (CCK) is a hormone that stimulates the release of digestive enzymes, including lipase, but it is not directly involved in emulsification.
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Which component of protein contains nitrogen?
- A. Amino group
- B. Carboxyl group
- C. Peptide bond
- D. Side chain
Correct Answer: A
Rationale: The correct answer is the amino group. Amino groups are functional groups found in amino acids, which are the building blocks of proteins. These groups contain nitrogen and are essential for the structure and function of proteins. The carboxyl group (choice B) contains carbon, oxygen, and hydrogen, while the peptide bond (choice C) is a covalent bond formed between amino acids in a protein chain. The side chain (choice D) refers to the unique chemical structure attached to the central carbon of an amino acid and varies among different amino acids, but it does not specifically contain nitrogen.
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.
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 release of gastric secretions is stimulated by nerve and hormonal stimuli and the:
- A. ingestion of water.
- B. swallowing reflex.
- C. presence of food in the stomach.
- D. closing of the pyloric sphincter.
Correct Answer: C
Rationale: The correct answer is C: 'presence of food in the stomach.' Gastric secretions are stimulated when food enters the stomach, triggering nerve and hormonal responses. This process prepares the stomach for digestion. Choices A, B, and D are incorrect because ingesting water, swallowing reflex, and the closing of the pyloric sphincter do not directly stimulate the release of gastric secretions.
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.