Nursing Elites

1. Pepsinogen secreted by the gastric cells is converted into pepsin by:

• A. enterokinase
• B. hydrochloric acid
• C. gastric lipase
• D. pancreatic lipase

Correct answer: B

Rationale: Pepsinogen is converted into its active form, pepsin, by hydrochloric acid in the stomach. Hydrochloric acid helps in unfolding the pepsinogen molecule to transform it into pepsin, which is crucial for protein digestion. Therefore, the correct answer is hydrochloric acid (choice B). Enterokinase (choice A) is an enzyme produced in the small intestine that activates trypsinogen into trypsin, not pepsinogen. Gastric lipase (choice C) is an enzyme that digests fats, not involved in converting pepsinogen to pepsin. Pancreatic lipase (choice D) is an enzyme produced by the pancreas that aids in breaking down fats in the small intestine, not part of the process of pepsin activation.

2. Plasma lipoproteins contain varying amounts of:

• A. ascorbic acid.
• B. triglycerides.
• C. lecithin.
• D. glucose.

Correct answer: B

Rationale: The correct answer is B: triglycerides. Plasma lipoproteins, such as LDL and HDL, contain triglycerides, cholesterol, and other fats. Ascorbic acid (choice A) is not typically found in plasma lipoproteins; it is a form of vitamin C. Lecithin (choice C) is a phospholipid found in cell membranes but is not a major component of plasma lipoproteins. Glucose (choice D) is a type of sugar and is not a primary component of plasma lipoproteins.

3. 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.

4. From where are trypsin and chymotrypsin secreted?

• A. Small intestine.
• B. Liver.
• C. Stomach.
• D. Pancreas.

Correct answer: D

Rationale: Trypsin and chymotrypsin are enzymes involved in protein digestion. These enzymes are secreted by the pancreas, not the small intestine, liver, or stomach. The pancreas plays a crucial role in producing digestive enzymes that aid in breaking down proteins in the small intestine. The small intestine is the site where these enzymes act, not where they are secreted. The liver is responsible for producing bile, not digestive enzymes. The stomach secretes gastric juices but not trypsin and chymotrypsin. Therefore, the correct answer is the pancreas.

5. A chemical feature that distinguishes a saturated fatty acid from an unsaturated fatty acid is the:

• A. arrangement of carbon atoms.
• B. number of oxygen molecules.
• C. number of double bonds.
• D. food source.

Correct answer: C

Rationale: The correct answer is C. Saturated fatty acids have no double bonds between carbon atoms, while unsaturated fatty acids have one or more double bonds. Therefore, the number of double bonds is the chemical feature that distinguishes a saturated fatty acid from an unsaturated fatty acid. Choices A, B, and D are incorrect because the distinguishing factor between saturated and unsaturated fatty acids lies in the presence or absence of double bonds, not in the arrangement of carbon atoms, number of oxygen molecules, or food source.

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