Nursing Elites

1. The lining of the stomach and intestine is protected from self-digestion by:

• A. pepsinogen.
• B. bile.
• C. mucus.
• D. fat.

Correct answer: C

Rationale: The correct answer is C: mucus. Mucus forms a protective barrier that prevents the stomach and intestine from digesting themselves. Pepsinogen (choice A) is an inactive form of pepsin, a digestive enzyme, and does not protect the stomach lining. Bile (choice B) aids in the digestion and absorption of fats but does not protect the stomach lining. Fat (choice D) is a nutrient and energy source; it does not play a role in protecting the stomach and intestine from self-digestion.

2. Where does the absorption of most nutrients occur?

• A. Large intestine.
• B. Small intestine.
• C. Stomach.
• D. Mouth.

Correct answer: B

Rationale: The absorption of most nutrients occurs in the small intestine. This is where digested food is broken down further and absorbed into the bloodstream through the intestinal walls. The large intestine primarily absorbs water and electrolytes, while the stomach mainly aids in digestion by breaking down food with gastric juices. The mouth is responsible for the initial mechanical breakdown of food through chewing and the enzymatic action of saliva, but absorption does not occur there.

3. The number of kilocalories provided by a food that contains 22g of fat is:

• A. 88
• B. 132
• C. 154
• D. 198

Correct answer: D

Rationale: The correct answer is D. Fat provides 9 kcal per gram, so 22 grams of fat will provide 198 kcal (22g * 9 kcal/g = 198 kcal). Choice A (88) is incorrect because it miscalculates the kcalories. Choice B (132) is incorrect as it does not consider the correct kcaloric value of fat. Choice C (154) is incorrect as it also does not calculate the kcalories accurately based on the fat content.

4. 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.

5. In an analysis of the amino acid composition of foods, the amino acid occurring in the smallest amount is called:

• A. indispensable.
• B. dispensable.
• C. complementary.
• D. limiting.

Correct answer: D

Rationale: The correct answer is D, 'limiting.' In the analysis of the amino acid composition of foods, the amino acid that occurs in the smallest amount is referred to as the limiting amino acid. This term is used because when one essential amino acid is deficient, it limits the synthesis of proteins, making it crucial in determining protein quality. Choices A, B, and C are incorrect. 'Indispensable' and 'dispensable' refer to the essentiality of amino acids, and 'complementary' does not describe the concept of the amino acid occurring in the smallest amount.

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