Nokea
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.
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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.
Which phase of metabolism makes growth and repair possible?
- A. digestion
- B. catabolism
- C. anabolism
- D. ketosis
Correct Answer: C
Rationale: Anabolism is the phase of metabolism responsible for building up and repairing tissues in the body. It involves processes that require energy to synthesize complex molecules from simpler ones. Digestion (choice A) is the process of breaking down food into simpler substances for absorption. Catabolism (choice B) involves the breakdown of complex molecules into simpler ones with the release of energy. Ketosis (choice D) is a metabolic state where the body uses fat as the primary source of energy, which is not directly related to growth and repair.
Infections are common in people who have inadequate protein intake because of an insufficient quantity of:
- A. insulin.
- B. lipoprotein.
- C. antibodies.
- D. albumin.
Correct Answer: C
Rationale: Inadequate protein intake can lead to a decrease in antibody production, making individuals more susceptible to infections. Insulin (Choice A) is a hormone involved in regulating blood sugar levels, not related to protein intake. Lipoprotein (Choice B) is a type of lipid-protein complex involved in lipid transport, not directly related to antibody production. Albumin (Choice D) is a protein that helps maintain oncotic pressure and carries various substances in the blood, but it is not primarily responsible for fighting infections like antibodies.
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.
Which of the following is an example of a complete protein?
- A. Milk
- B. Soy
- C. Sesame seeds
- D. Sweet potato
Correct Answer: A
Rationale: The correct answer is A, Milk. Milk is considered a complete protein as it contains all the essential amino acids required by the body. Soy (choice B) is also a complete protein, containing all essential amino acids. Sesame seeds (choice C) and sweet potato (choice D) are not complete proteins as they lack one or more essential amino acids needed by the body.