Metabolic transformation and conjugation usually results in an increase of a substance biological activity:

Correct Answer: B

Rationale: Correct Answer: B (FALSE) Rationale: 1. Metabolic transformation and conjugation often lead to the inactivation or reduction of a substance's biological activity. 2. Conjugation typically involves adding a polar group to increase the substance's water solubility for excretion. 3. Metabolic transformations can lead to the formation of less active or inactive metabolites. 4. Therefore, the correct answer is FALSE as these processes usually decrease the biological activity of a substance. Summary: - Choice A (TRUE) is incorrect as metabolic transformation and conjugation generally decrease, not increase, a substance's biological activity. - Choice C (All) and Choice D (None) are also incorrect as the correct answer is specifically B, indicating a decrease in biological activity.

Correct Answer: B

Rationale: The correct answer is B because carbachol causes miosis (pupillary constriction) instead of mydriasis (pupillary dilation). Carbachol stimulates muscarinic receptors causing constriction of the pupil. Choices A, C, and D are incorrect because carbachol does decrease intraocular pressure, exerts both nicotinic and muscarinic effects, and is resistant to acetylcholinesterase, respectively.

Correct Answer: A

Rationale: The correct answer is A: Benztropine. Benztropine is an anticholinergic drug that helps improve symptoms of Parkinson's disease by blocking excess acetylcholine in the brain, thus restoring a balance between dopamine and acetylcholine. This helps alleviate tremors, muscle stiffness, and other motor symptoms associated with Parkinson's. Summary of other choices: B: Edrophonium is a reversible acetylcholinesterase inhibitor used for diagnosing myasthenia gravis. C: Succinylcholine is a depolarizing neuromuscular blocker used for muscle relaxation during surgeries. D: Hexamethonium is a ganglionic blocker used to lower blood pressure.

Correct Answer: C

Rationale: The correct answer is C because a relatively pure alpha agonist primarily acts on alpha receptors in blood vessels causing vasoconstriction, leading to increased peripheral arterial resistance and reflex bradycardia. This results in an increase in blood pressure and venous return. Since alpha agonists primarily target blood vessels, they do not have a direct effect on blood vessels. Choices A, B, and D are incorrect as they are known effects of alpha agonists.

Correct Answer: B

Rationale: The correct answer is B: Metoprolol. Metoprolol is a beta1-selective antagonist, meaning it selectively blocks beta1-adrenergic receptors. This specificity results in decreased heart rate and contractility without affecting beta2 receptors, which are primarily found in the lungs. Choice A, Propranolol, is a non-selective beta blocker that blocks both beta1 and beta2 receptors. Choice C, Carvedilol, is a non-selective beta blocker with additional alpha-blocking activity. Choice D, Sotalol, is a non-selective beta blocker with Class III antiarrhythmic properties. Therefore, the correct answer is B as it is the only beta1-selective antagonist among the options provided.