Which amino acid is not found in protein?

Correct Answer: A

Rationale: The correct answer is A: ornithine. Ornithine is not a standard amino acid found in protein structures but is involved in the urea cycle. Arginine, valine, and aspartic acid are all standard amino acids that are commonly found in proteins. Ornithine is not incorporated into proteins during translation, making it the correct choice.

Correct Answer: C

Rationale: The correct answer is C: 2. The posterior pituitary produces two hormones: oxytocin and vasopressin. Oxytocin is involved in childbirth and breastfeeding, while vasopressin helps regulate water balance in the body. Option A is incorrect because the posterior pituitary does produce hormones. Option B is incorrect as there are two hormones produced, not just one. Option D is incorrect as the posterior pituitary does not produce six hormones. In summary, the posterior pituitary gland produces two hormones, making option C the correct answer.

Correct Answer: B

Rationale: The correct answer is B (3 litres). The average adult human stomach secretes about 2-3 liters of gastric juice per day. This amount is necessary for the effective digestion of food, as gastric juice contains hydrochloric acid, enzymes, and mucus. Option A (1.5 litres) is too low for daily gastric juice secretion. Option C (4 litres) is too high and could lead to hypersecretion or other digestive issues. Option D is incomplete and does not provide a valid answer. Therefore, option B is the most accurate in reflecting the average daily secretion of gastric juice.

Correct Answer: C

Rationale: The correct answer is C: Kidney gland. The endocrine system consists of glands that secrete hormones directly into the bloodstream to regulate various bodily functions. The kidney is not a gland; it is an organ responsible for filtering waste from the blood and producing urine. The adrenal gland, thyroid gland, and pituitary gland are all part of the endocrine system as they secrete hormones. In summary, the kidney does not secrete hormones and therefore is not considered a gland in the endocrine system.

Correct Answer: A

Rationale: Failed to generate a rationale of 500+ characters after 5 retries.