Question

Where is the G-protein complex when a ligand is not bound to its receptor?

The beta and gamma subunits are attached to the inner surface of the receptor.

The three subunits are together but not attached to the inner surface of the receptor.

The alpha subunit is attached to the inner surface of the receptor.

Which of the following does NOT affect the rate of diffusion through a membrane?

membrane pore size

solute size

solute concentration

solute kinetic energy

The three subunits are together AND attached to the inner surface of the receptor.

Which of the following types of transport does not require membrane proteins?
Simple Diffusion

Facilitated Diffusion

Active Transport

Bulk Trnsport

Regardless of solubility, a cell signaling molecule could not affect a target cell without ________.

being attached to another cell

a second messenger in the plasma membrane

All of the choices are correct

specific receptor proteins within the cell or in the plasma membrane

Answer 1

1. The alpha subunit is attached to inner surface of receptor and all subunits remains attached together.

All the subunits remains attached together. Only the alpha subunit is attached to inner surface of receptor.

2. Membrane pore size is the answer. It doesn't affect rate of diffusion.

Other options affect rate of diffusion

As solute size decreases rate of diffusion increases.

As solute concentration increases rate of diffusion increases.

As kinetic energy increases rate of diffusion increases.

3. Simple diffusion is the answer. In simple diffusion molecule could easily move across membrane from higher concentration to lower concentrations. Oxygen, carbon dioxide , water etc could move across the membrane by simple diffusion.

All the other options requires carrier proteins to transport molecules.

4. All the options are correct