33 Year 3: Basic Pharmacology II exam questions on MBPL3621 Introduction to Pharmacology Quiz 1 for medical students. Includes MCQs, answers, explanations and w
This MCQ set contains 33 questions on MBPL3621 Introduction to Pharmacology Quiz 1 in the Year 3: Basic Pharmacology II unit. Each question includes the correct answer and a detailed explanation for active recall and exam preparation.
Correct answer: A – Absorption
Absorption is the movement of a drug from its site of administration into the bloodstream. This process is essential for the drug to reach systemic circulation and eventually its site of action. ---
Correct answer: A – True
Receptor agonists bind to receptors and activate them, producing a biological response. This is the mechanism by which many drugs exert their therapeutic effects. ---
Correct answer: B – Plasma protein binding
Only free (unbound) drug molecules can be filtered through the glomerulus. Drugs bound to plasma proteins are too large to pass through the glomerular membrane, so plasma protein binding directly affects glomerular filtration. ---
Correct answer: B – Concentration of a substance in plasma
Volume of distribution (Vd) is calculated using the formula: Vd = Dose / Plasma concentration. It represents the theoretical volume needed to contain the total amount of drug at the same concentration as in plasma. ---
Correct answer: B – Rate of metabolism and excretion
The illustration focuses on pharmacokinetics (how the body processes the drug), not pharmacodynamics (drug effects). Metabolism and excretion are pharmacokinetic processes that determine drug concentration over time. ---
Correct answer: A – True
Strength refers to the amount of drug in a dosage form (e.g., 500 mg tablet). Higher doses contain more drug and therefore have greater strength, though this is different from potency, which is a comparative measure. ---
Correct answer: B – Drug biotransformation in the organism
Pharmacokinetics describes what the body does to the drug, including absorption, distribution, metabolism (biotransformation), and excretion (ADME). ---
Correct answer: C – Have low oral bioavailability
First-pass metabolism occurs when orally administered drugs are metabolized in the liver before reaching systemic circulation, reducing the amount of active drug available and thus decreasing oral bioavailability. ---
Correct answer: C – None of the choices
Bioavailability is the percentage of administered dose that reaches systemic circulation in the UNCHANGED (active) form, not "changed form" as stated in option E. None of the provided options correctly defines bioavailability. ---
Correct answer: A – False -
Receptor antagonists bind to receptors but do not activate them. They block the receptor and prevent agonists from binding, thereby inhibiting a response rather than producing one. ---
Correct answer: E – All the choices
Drugs can be derived from multiple sources including animals (e.g., insulin), plants (e.g., morphine), and synthetic/chemical synthesis (e.g., aspirin). Modern pharmaceuticals use all these sources. ---
Correct answer: D – Absorption
Bioavailability is primarily determined by absorption and first-pass metabolism. The extent and rate of absorption directly affect how much drug reaches systemic circulation. ---
Correct answer: D – Convert lipid soluble drugs into non-lipid soluble metabolites
Biotransformation (metabolism) typically converts lipid-soluble drugs into more water-soluble (non-lipid soluble) metabolites, facilitating their excretion through urine or bile. ---
Correct answer: A – Single to a daily dose of an administrated drug
Volume of distribution is the theoretical volume necessary to contain the total amount of administered drug at the same concentration observed in blood plasma. It indicates the extent of drug distribution in body tissues. ---
Correct answer: A – Extent of absorption and hepatic first-pass effect
Bioavailability is primarily determined by how much drug is absorbed and how much undergoes first-pass metabolism in the liver before reaching systemic circulation. ---
Correct answer: A – The ED50 is a measure of drug's efficacy
ED50 (effective dose in 50% of population) is a measure of potency, not efficacy. Efficacy refers to the maximum effect a drug can produce, regardless of dose. ---
Correct answer: C – CYP 3A4
CYP3A4 is responsible for metabolizing approximately 50% of all drugs and is frequently involved in clinically significant drug-drug interactions. ---
Correct answer: C – An inactive drug that is transformed in the body to an active metabolite
A prodrug is administered in an inactive or less active form and is metabolized in the body to produce the active drug. This approach can improve drug absorption, distribution, or reduce side effects. ---
Correct answer: C – Distribution
Distribution involves the movement of drug from circulation to tissues and is affected by barriers (like blood-brain barrier), tissue binding, and plasma protein binding. ---
Correct answer: C – Plasma half life
Plasma half-life (t½) is the time required for the plasma concentration of a drug to decrease by 50%. It is the primary parameter used to monitor and characterize drug elimination. ---
Correct answer: A – Glucuronidation
Glucuronidation is the most common Phase II conjugation reaction, involving the addition of glucuronic acid to drugs or their metabolites, making them more water-soluble for excretion. ---
Correct answer: A – Absence of pores in the brain capillary endothelium
The blood-brain barrier has tight junctions between endothelial cells with no pores, making it difficult for many drugs to penetrate. Only lipid-soluble drugs or those with specific transporters can cross easily. ---
Correct answer: A – Metabolism
This describes first-pass metabolism, where orally administered drugs are metabolized in the liver (or gut wall) before reaching systemic circulation, reducing bioavailability. ---
Correct answer: D – Inhalation provides slow access to the general circulation
Inhalation actually provides rapid access to systemic circulation due to the large surface area and rich blood supply of the lungs, not slow access. ---
Correct answer: B – Distribution
Distribution is the process by which a drug reversibly moves from the bloodstream into tissues and the site of action. ---