SZABMU MDCAT 2025 past paper, Code 2

Answer: D. Aldosterone

Aldosterone is a steroid hormone, meaning it is derived from cholesterol and is lipid-based. Insulin, FSH, and oxytocin are protein or peptide hormones, not lipid-based.

Answer: C. They are steroids

Aldosterone, sex hormones (like testosterone and estrogen), and cortisone are all synthesized from cholesterol and share a

Answer: C. Helper T-cells

Helper T-cells are crucial because they release cytokines that signal and activate both B-cells and T-cells to proliferate and differentiate. Plasma cells are effector B-cells that produce antibodies and do not stimulate other lymphocytes. Memory cells are long-lived cells that respond quickly upon re-exposure to an antigen but don't initiate the primary immune response by stimulating naive lymphocytes. Neutrophils are phagocytic cells important for innate immunity and don't directly regulate lymphocyte division.

Answer: B. Thymus

The thymus is the primary site for T-cell maturation, a crucial process for adaptive immunity. While the spleen filters blood and participates in immune responses, and the liver and kidneys have distinct roles unrelated to T-cell maturation, the thymus is uniquely responsible for this specific immune cell development.

Answer: C. Hard palate

The hard palate is the bony anterior part of the roof of the mouth, formed by the fusion of the palatine processes of the maxilla and the horizontal plates of the palatine bones. The soft palate, while part of the roof of the oral cavity, is made of muscle and is located posterior to the hard palate.

Answer: B. enantiomers

The correct answer is B because (+) tartaric acid and (-) tartaric acid are non-superimposable mirror images of each other, which is the definition of enantiomers. They have opposite configurations at their chiral centers. Option A is incorrect because geometric isomers arise from restricted rotation around a double bond or in a ring, which isn't the case here.

Answer: A. 3 double bonds

Benzene reacts with three molecules of chlorine under UV light via addition reaction, forming hexachlorocyclohexane. This addition across the double bonds indicates that benzene possesses three double bonds, which break

Answer: B. molecules are in constant random motion

Molecules of both ideal and real gases are in constant, random motion, a fundamental principle of kinetic theory. While ideal gases have perfectly elastic collisions and no intermolecular forces (options A and C are incorrect), and point masses (option D is incorrect), real gases exhibit some degree of inelasticity and attractive forces between molecules. Option B remains true for both as the basis of their gaseous state.

Answer: B. A quantum of energy with zero rest mass and zero charge

Photons are discrete packets of energy (quanta) that exhibit wave-particle duality. They have no rest mass and no electric charge, which is why option B is correct. Option A is incorrect because photons do not have mass or charge.

Answer: B. Rashid Khan wrote the book.

The sentence is in the active voice, meaning the subject (Rashid Khan) performs the action (writing the book). Option B uses the simple past tense "wrote," correctly indicating that the action was completed by the subject. Option A uses the present tense, implying an ongoing or habitual action, which doesn't fit the context of a completed book. Option C is grammatically incorrect as "written" is a past participle and requires a helping verb. Option D incorrectly uses the base form "write" after "has."