Which is WRONG about dopamine:

Correct Answer: A

Rationale: The correct answer is A because dopamine is not effective orally due to its inability to cross the blood-brain barrier. Dopamine is mainly metabolized by MAO and COMT enzymes (B). It is primarily excreted in the urine as homovanillic acid, not vanillylmandelic acid (C). Dopamine stimulates dopamine receptors (D), not α, β1, and D receptors.

Correct Answer: D

Rationale: The correct answer is D: Blockade of acetylcholine release from all cholinergic nerves. Botulinum toxin exerts its effects by inhibiting the release of acetylcholine from presynaptic nerve terminals at neuromuscular junctions. This leads to muscle paralysis, which is a characteristic feature of botulism. A: Massive release of adrenaline from the adrenal medulla is incorrect because botulinum toxin does not affect the adrenal medulla or adrenaline release. B: Blockade of alpha and beta adrenergic receptors is incorrect because botulinum toxin does not directly block adrenergic receptors. C: Stimulation of acetylcholinesterase enzyme is incorrect because botulinum toxin inhibits acetylcholine release rather than stimulating acetylcholinesterase. In summary, the correct answer D directly correlates with the mechanism of action of Botulinum toxin, while the other choices are unrelated to how Botulinum toxin exerts

Correct Answer: B

Rationale: The correct answer is B because phenylephrine stimulates α-adrenergic receptors, leading to vasoconstriction and mucous membrane decongestion. This action helps relieve nasal congestion. Choice A is incorrect because phenylephrine does not block muscarinic receptors. Choice C is incorrect because phenylephrine does not block β-adrenergic receptors. Choice D is incorrect because phenylephrine is not typically used for managing hypertension.

Correct Answer: B

Rationale: The correct answer is B because it accurately pairs the endocrine glands with their corresponding hormones. The adrenal gland secretes adrenaline, and the pancreas secretes insulin. Adrenaline is produced by the adrenal gland, not the ovary, making choices A and D incorrect. The pancreas secretes insulin, not adrenaline, making choice C incorrect. In summary, choice B is correct because it correctly matches the adrenal gland with adrenaline and the pancreas with insulin, while the other choices mix up the glands and hormones.

Correct Answer: A

Rationale: The correct answer is A. Catalysts decrease the activation energy required for a reaction, speeding up the reaction without being consumed in the process. They provide an alternative pathway for the reaction to proceed, facilitating the reaction without being altered themselves. This is why they are unchanged at the end of the reaction. Choice B is incorrect because catalysts are not used up in the reaction. Choices C and D are also incorrect as catalysts do not increase the time taken for a reaction to finish nor are they consumed in the reaction.