KMU MDCAT 2025 past paper, Code D

Answer: B. Absorption of vitamin B12 in the intestine

Intrinsic factor binds to vitamin B12 in the stomach, forming a complex that is then absorbed in the ileum of the small intestine. Option A is incorrect because hydrochloric acid, not intrinsic factor, activates pepsinogen. Option D is incorrect because bicarbonate from the pancreas neutralizes stomach acid in the duodenum.

Answer: B. Guanine

The correct answer is **B) Guanine**. In DNA, Adenine always pairs with Thymine, and Cytosine always pairs with Guanine. This is known as complementary base pairing. **A) Adenine** is the most tempting wrong option because it also pairs with a pyrimidine base, but it pairs with Thymine, not Cytosine.

Answer: C. Enveloped capsid virus

Influenza virus possesses an outer lipid envelope derived from the host cell membrane, which encloses the viral capsid. This characteristic makes it an enveloped virus according to morphological classification. While it has a helical capsid *within* the envelope, the presence of the envelope is the primary distinguishing feature in this classification scheme.

Answer: D. Testes

The testes are the primary reproductive organs responsible for producing sperm and male hormones, not accessory glands. The seminal vesicles, prostate gland, and bulbourethral glands are all accessory glands that contribute fluids to semen.

Answer: C. Ventricular systole

The semilunar valves (aortic and pulmonary) open when the pressure inside the ventricles exceeds the pressure in the aorta and pulmonary artery, respectively. This pressure increase occurs during ventricular systole, which is the contraction phase of the ventricles. While atrial systole (A) precedes ventricular contraction, it's the ventricular pressure that directly drives the semilunar valves open.

Answer: C. Inertia

The passenger falls backward due to inertia, which is the tendency of an object to resist changes in its state of motion. The passenger's body, due to inertia, tends to remain at rest while the bus moves forward. Deceleration (D) is the rate of decrease in velocity, which is not directly applicable here as the bus is accelerating.

Answer: B. Decreases continuously and becomes zero at the extreme position

As the particle moves from the mean position to the extreme position, its velocity decreases, and since kinetic energy is directly proportional to the square of velocity ($KE = \frac{1}{2}mv^2$), the kinetic energy also decreases continuously. At the extreme position, the particle momentarily stops, so its velocity is zero, resulting in zero kinetic energy. Option A is incorrect because kinetic energy decreases. Option C is incorrect because kinetic energy varies with velocity. Option D is incorrect because kinetic energy is maximum at the mean position where velocity is maximum.

Answer: A. 9% increase

Water has a unique property where its density is highest at 4°C. As water cools from 4°C to 0°C, its density decreases, meaning its volume increases. This expansion is about 9%, which is why ice floats. Option C is a distractor, representing a larger, incorrect percentage of volume change.

Answer: C. BF₃

Boron trifluoride (BF₃) has boron as its central atom, which is bonded to three fluorine atoms. This arrangement results in a trigonal planar geometry, where all atoms lie in the same plane. Ammonia (NH₃) has a trigonal pyramidal shape due to the lone pair on nitrogen, and water (H₂O) has a bent shape for the same reason. Methane (CH₄) has a tetrahedral geometry, which is not planar.

Answer: D. Subject

The gerund phrase "Jogging every morning" acts as the subject of the sentence because it performs the action of the verb "improves." It is the thing that is doing the improving. Option A is incorrect because the gerund phrase is not receiving the action of a verb, and while it is the subject, it is not specifically a predicate noun.