Nokea
What is the chemical structure that forms the base component of an amino acid?
- A. carboxyl group
- B. carbon chain
- C. radicals
- D. amino group
Correct Answer: D
Rationale: The correct answer is the amino group. Amino acids consist of an amino group (NH2), a carboxyl group (COOH), a hydrogen atom, and a variable side chain attached to a central carbon atom. The amino group is essential for the formation of proteins. The carboxyl group is not the base component but another important functional group in amino acids. Carbon chain and radicals are not specific chemical structures that form the base component of an amino acid.
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Which term describes the amino acids that are synthesized by the body?
- A. essential amino acids.
- B. nonessential amino acids.
- C. complete amino acids.
- D. incomplete amino acids.
Correct Answer: B
Rationale: The correct answer is B: nonessential amino acids. Nonessential amino acids can be synthesized by the body, so they do not need to be obtained through the diet. Essential amino acids, choice A, must be obtained from the diet because the body cannot produce them. Choices C and D, complete and incomplete amino acids respectively, do not accurately describe the classification of amino acids based on synthesis by the body.
In addition to active transport, which process is involved in absorbing food in the small intestine?
- A. pinocytosis
- B. excretion
- C. phagocytosis
- D. electrochemical diffusion
Correct Answer: A
Rationale: The correct answer is pinocytosis. Pinocytosis is a process where cells in the small intestine absorb nutrients by engulfing them. This process is different from phagocytosis, which involves engulfing large particles, and excretion, which is the removal of waste products. Electrochemical diffusion is not directly involved in the absorption of food in the small intestine.
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.
Feces are composed mainly of bacteria, mucosal cells, mucus, and what else?
- A. bile
- B. enzymes
- C. fiber
- D. chyme
Correct Answer: C
Rationale: The correct answer is 'C: fiber.' Feces are primarily made up of indigestible material, such as fiber. Bile (choice A) is produced by the liver to aid in digestion but is not a major component of feces. Enzymes (choice B) are involved in digestion but are not a significant component of feces. Chyme (choice D) is the semi-fluid mass of partially digested food that moves from the stomach to the small intestine and is not a major component of feces.
What are probiotics?
- A. Indigestible carbohydrates that promote growth of health-promoting bacteria.
- B. Antibiotics that prevent growth of harmful bacteria.
- C. Nutritional supplements of health-promoting bacteria.
- D. Commercial fiber supplements that have a laxative effect.
Correct Answer: C
Rationale: Probiotics are live bacteria that are beneficial for gut health and are often taken as supplements. They are not indigestible carbohydrates (Choice A), antibiotics (Choice B), or commercial fiber supplements (Choice D). Probiotics contain live strains of good bacteria that help maintain a healthy balance in the gut microbiome.