How is the enzyme trypsin activated?

Correct Answer: D

Rationale: The correct answer is D: By enterokinase. Trypsin is activated by enterokinase, an enzyme secreted by the small intestine. Enterokinase plays a crucial role in converting trypsinogen into its active form, trypsin. Choices A, B, and C are incorrect because trypsin is specifically activated by enterokinase, not by zymogen, bile, or gastrin.

Correct Answer: A

Rationale: Albumin is the correct answer. It is a plasma protein that helps maintain osmotic pressure, thereby playing a vital role in regulating fluid balance in the body. Fibrinogen is involved in blood clotting, not fluid balance. Hemoglobin is responsible for oxygen transport in red blood cells, not fluid balance. Collagen is a structural protein found in connective tissues, not directly involved in fluid balance.

Correct Answer: B

Rationale: A nursing infant receives antibodies from its mother through the absorption of antibodies present in breast milk. Choice A is incorrect as anabolism and catabolism refer to metabolic processes, not the transfer of antibodies. Choice C is incorrect as the infant does not need to synthesize antibodies but directly receives them. Choice D is incorrect because while genetic inheritance plays a role in the immune system, in this case, the direct transfer of antibodies occurs through breast milk.

Correct Answer: C

Rationale: The correct answer is C, kwashiorkor. Kwashiorkor is a type of protein-energy malnutrition characterized by edema, hypoalbuminemia, skin lesions, and fatty liver. Edema is a key feature of kwashiorkor due to hypoalbuminemia, which leads to decreased oncotic pressure. Marasmus (choice B) is a form of severe malnutrition characterized by energy deficiency without significant protein deficiency, resulting in severe wasting. Cachexia (choice A) is a syndrome characterized by weight loss, muscle atrophy, fatigue, weakness, and loss of appetite in someone who is not actively trying to lose weight. Sarcopenia (choice D) is the age-related loss of muscle mass and function.

Correct Answer: A

Rationale: The correct answer is 'tissue and plasma.' Protein turnover involves the continuous exchange of proteins between body tissues and the bloodstream (plasma) as part of normal metabolic processes. This process ensures a balance in protein levels throughout the body. Choices B, C, and D are incorrect as they do not represent the primary sites for protein turnover in the body.