Which tissue has the highest rate of protein turnover?

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: 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: A

Rationale: The correct answer is A: Forming neurotransmitters. Methionine, tyrosine, and tryptophan are important amino acids involved in the production of neurotransmitters in the body. Neurotransmitters are chemical messengers that transmit signals across nerve cells, influencing various functions such as mood, memory, and muscle control. Choices B, C, and D are incorrect because these amino acids do not primarily play a role in blocking protein breakdown, increasing insulin and thyroxine production, or decreasing energy expenditure.

Correct Answer: A

Rationale: Dextrins are a type of polysaccharides formed during the breakdown of starch. Choice A is correct because dextrins are indeed polysaccharides, not the end products of starch digestion (Choice B). They are not formed in the liver (Choice C) nor rapidly excreted (Choice D).

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: 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: D

Rationale: The correct term for a vegetarian diet that includes both dairy foods and eggs is 'ovolactovegetarian.' This term specifically indicates the inclusion of eggs ('ovo') and dairy ('lacto') in the diet. Choice A, 'lactovegetarian,' is incorrect because it only includes dairy products without eggs. Choice B, 'vegan,' is incorrect as it excludes all animal products, including dairy and eggs. Choice C, 'semi-vegetarian,' is incorrect as it is a term used for individuals who occasionally eat meat, poultry, or fish but primarily follow a plant-based diet.

Correct Answer: C

Rationale: The correct answer is C: Small intestine. The majority of lipid digestion occurs in the small intestine, where bile and pancreatic lipase are active. Lipids are broken down into fatty acids and glycerol in the small intestine. Choices A, B, and D are incorrect because the mouth and stomach play minor roles in lipid digestion, and the large intestine is mainly responsible for absorbing water and electrolytes from the indigestible food residues.

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.