Test on Biomembranes and Membrane Transport Mechanisms

Question 1: Van't Hoff's relation for ideal liquids incorporates the van 't Hoff's correcting coefficient (i).

A. Ano

B. Ne

Explanation: According to the study materials, Van't Hoff's relation for ideal liquids is 𝜋 = 𝑐𝑅𝑇, while for real solutions it is 𝜋 = 𝑖𝑐𝑅𝑇, where 'i' is the van 't Hoff's correcting coefficient. Therefore, the relation for ideal liquids does not incorporate the 'i' coefficient.

Question 2: Which of the following statements accurately describes the mechanism of group translocation?

A. The substance's chemical structure remains unchanged during transport.

B. Once a substance is inside the cell, the cytoplasmic membrane becomes impermeable to it.

C. Group translocation always requires the delivery of energy for transport.

D. The transported substance can easily exit the cell after entering through group translocation.

Explanation: Group translocation is characterized by the change in the structure of a compound during transport. Once the substance is inside, the cytoplasmic membrane becomes impermeable to it, ensuring it remains within the cell. This process can occur with or without the delivery of energy.

Question 3: The presence of cholesterol in a biomembrane increases the fluidity of the membrane.

A. Ano

B. Ne

Explanation: The study materials state that cholesterol decreases the shift of phospholipids, which leads to a decrease in the fluidity of the membrane.

Question 4: Longer saturated fatty acid chains generally lead to increased fluidity of the membrane.

A. Ano

B. Ne

Explanation: The study materials state that 'longer fatty acids – lower fluidity of membrane' in the context of saturated fatty acids.

Question 5: According to the fluid mosaic membrane model described, how do the movements of lipid lateral shift and flip-flop compare?

A. Lipid lateral shift is slower than flip-flop.

B. Lipid flip-flop is slower than lateral shift.

C. Both lipid lateral shift and flip-flop occur at the same speed.

D. Lipids only exhibit lateral shift, not flip-flop.

Explanation: The study materials state that the biomembrane model features "lateral shift of lipids vs. flip-flop (slower)", indicating that flip-flop is the slower movement compared to lateral shift.