DUHS MDCAT 2022 past paper, Code B

Answer: E. Virus

Hepatitis is an inflammation of the liver, and the most common causes are viral infections. Options A, B, C, and D are incorrect because protozoans, algae, bacteria, and fungi, while capable of causing various diseases, are not the primary or typical agents responsible for hepatitis.

Answer: A. Lungs

The frog draws fresh air into its bucco-pharyngeal cavity by closing its nostrils and lowering the floor of its mouth. Simultaneously, the glottis closes, trapping the old air under pressure in the lungs. This pressure difference forces the stale air out of the lungs when the floor of the mouth is raised, and fresh air enters the bucco-pharyngeal cavity. Option A is correct because the lungs are where the old air is retained under pressure.

Answer: E. Acylglycerol

Acylglycerols, specifically triglycerides, are the primary form of stored energy in both plants and animals due to their high energy density. Phospholipids are crucial for cell membranes, while carotenoids and terpenoids/terpenes are involved in pigment and signaling roles, not energy storage.

Answer: C. 1-4 glycosidic linkage

The correct answer is C because amylose is a linear polymer of glucose units linked by $\alpha$-1,4 glycosidic bonds. Option A is incorrect because 1-2 glycosidic linkages are rare and not found in amylose. Options B and D are incorrect as 2-3 and 1-3 glycosidic linkages, respectively, do not form the linear structure characteristic of amylose.

Answer: C. The behavior of gases

The kinetic molecular theory describes the motion of particles in a gas and how this motion relates to macroscopic properties like pressure, volume, and temperature. This theory is specifically designed to explain the observed behavior of gases. While atoms are made up of the other options listed (mass number, atom number, electrons, and neutrons), the kinetic molecular theory does not directly explain these fundamental atomic properties.

Answer: D. At high pressure & low temperature

Gases deviate from ideal behavior when their particles have significant volume and attractive forces. High pressure forces gas particles closer together, increasing the influence of intermolecular forces and particle volume. Low temperature reduces the kinetic energy of particles, making attractive forces more significant relative to their motion. Option C is tempting because high pressure is indeed a factor, but high temperature would increase kinetic energy, counteracting the deviations caused by pressure.

Answer: A. Aromatic alcohol

The compound C₆H₅CH₂OH is classified as an aromatic alcohol because it has a hydroxyl group (-OH) attached to a carbon atom that is directly bonded to a benzene ring (C₆H₅) via a methylene group (-CH₂-). Option B is incorrect because phenols have the hydroxyl group directly attached to the benzene ring.

Answer: C. 1.33 μF

The formula for equivalent capacitance ($C_{eq}$) of capacitors in series is $1/C_{eq} = 1/C_1 + 1/C_2$. Plugging in the given values, $1/C_{eq} = 1/2 + 1/4 = 3/4$. Therefore, $C_{eq} = 4/3 \approx 1.33 \mu F$. Option B is tempting because it might result from incorrectly adding the reciprocals or incorrectly inverting the sum.

Answer: A. 12volt

When cells are connected in series, their individual electromotive forces (emfs) add up to give the net emf of the combination. In this case, four cells, each with an emf of 3 volts, are connected in series, so the total emf is 3V + 3V + 3V + 3V = 12 volts. Option E (3 volt) is tempting as it is the emf of a single cell, but it ignores the series combination.

Answer: D. I will be moving to China.

Option D is correct because "China" is a proper noun and must be capitalized. The other options incorrectly capitalize "Moving" or "To" or fail to capitalize "China."