ADH has two actions, one on the kidney and the other on vascular smooth muscle, these actions are mediated by different receptors, different intracellular mechanisms, and different secondary messengers.

a. The major action of ADH is to increase the water permeability of principal cells in the late distal tubule and collecting duct.

b. The receptor for ADH on the principal cells is a V2 receptor, which is coupled to adenylyl cyclase via a Gs protein. 

c. The second messenger is cAMP, via phosphorylation steps, directs the insertion of water channels, aquaporin 2 (AQP2), in luminal membranes.

d. The receptor for ADH on the principal cells is a V1 receptor, which is coupled to phospholipase C via Gq protein.

Which one of the following combination of above statements is correct?

#Question id: 10534

#Unit 2. Cellular Organization

This experiment (shown in figure ) was performed at 37degree C. If the experiment were carried out at 10 degree C, what effect would you expect on the rate of diffusion? Why?

#Question id: 10533

#Unit 2. Cellular Organization

Following statements are regarding to the fluidity of a bilayer.

A. A lipid bilayer cools below a characteristic transition temperature, it undergoes a sort of phase change in which it becomes a liquid; that is, it loses its fluidity.

B. Above the transition temperature, the highly mobile lipids are in a state known as a liquid crystal.

C. The bilayer is thicker in the gel state than in the liquid crystal state due to the stiffening of the hydrocarbon tails at lower temperatures.

D. The transition temperature of a bilayer decreases with the chain length and the degree of saturation of its component fatty acid residues for the same reasons that the melting points of fatty acids increase with these quantities.

Which of the following combination is correct?

#Question id: 10532

#Unit 2. Cellular Organization

A  closed, self-sealing solvent-filled vesicles that are bounded by only a single bilayer, known as:

#Question id: 10531

#Unit 2. Cellular Organization

Flippases catalyze translocation of the aminophospholipids:

#Question id: 10530

#Unit 2. Cellular Organization

The transfer of a lipid molecule across a bilayer, a process termed:

#Question id: 2257

#Unit 2. Cellular Organization

Match the following property (Column I) with the transport mechanism (Column II).