Nursing Elites

1. What substance activates pepsinogen to pepsin?

• A. Bile
• B. Gastrin
• C. Secretin
• D. Hydrochloric acid

Correct answer: D

Rationale: The correct answer is D: Hydrochloric acid. Hydrochloric acid in the stomach plays a crucial role in converting pepsinogen into its active form, pepsin, which is necessary for digesting proteins. Bile (Choice A) is involved in the emulsification of fats, not in the activation of pepsinogen. Gastrin (Choice B) is a hormone that stimulates the secretion of gastric acid but does not directly activate pepsinogen. Secretin (Choice C) is a hormone that regulates the pH of the duodenum but is not responsible for the activation of pepsinogen.

2. Which of the following is a source of complete protein?

• A. Cereal grains.
• B. Beans.
• C. Nuts.
• D. Eggs.

Correct answer: D

Rationale: Eggs are considered a source of complete protein because they contain all the essential amino acids required by the body. The other options, cereal grains, beans, and nuts, do not provide all the essential amino acids in the necessary proportions to be classified as complete proteins.

3. Which tissue has the highest rate of protein turnover?

• A. Skin
• B. Intestinal mucosa
• C. Muscle
• D. Adipose tissue

Correct answer: B

Rationale: The correct answer is B: Intestinal mucosa. The intestinal mucosa has the highest rate of protein turnover due to its rapid cell renewal. The skin, muscle, and adipose tissue do not exhibit protein turnover rates as high as the intestinal mucosa. Skin cells turnover relatively slower compared to the rapid renewal of intestinal mucosa cells. Muscles have a moderate rate of protein turnover, while adipose tissue has a lower turnover rate compared to the other tissues mentioned.

4. 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.

5. Two amino acids are chemically joined by a:

• A. double bond.
• B. hydrogen bond.
• C. carboxyl bond.
• D. peptide bond.

Correct answer: D

Rationale: The correct answer is D, peptide bond. A peptide bond is formed through a dehydration synthesis reaction between the amine group of one amino acid and the carboxyl group of another amino acid. This bond is crucial in protein synthesis. Choices A, B, and C are incorrect. A double bond involves sharing two pairs of electrons, a hydrogen bond is a weak attraction between a hydrogen atom and an electronegative atom, and a carboxyl bond is not a common term in biochemistry.

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