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.

Correct Answer: C

Rationale: Chymotrypsin is an enzyme found in pancreatic secretions that plays a role in protein digestion. Rennin is primarily found in the stomach and is involved in milk digestion. Pepsin is also a stomach enzyme that aids in protein breakdown. Casein is a protein found in milk, not an enzyme involved in pancreatic secretions. Therefore, the correct answer is Chymotrypsin.

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.

Correct Answer: D

Rationale: Negative nitrogen balance occurs when the body loses more nitrogen than it gains. This imbalance is often seen in conditions like anorexia in older adults, where insufficient protein intake leads to muscle breakdown and negative nitrogen balance. Choices A, B, and C do not typically lead to negative nitrogen balance as seen in anorexia in older adults.

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.