Question

Which type of transport occurs when a membrane protein binds to a molecule on one side of the cell membrane, and then releases it on the other side?
a. active transport
b. exocytosis
c. facilitated diffusion
d. passive diffusion

Answer 1

Facilitated diffusion is the type of transport that occurs when membrane proteins bind to a molecule on one side of the cell membrane and then releases it on another side. An integral membrane protein provides continuous protein lined pathway through bilayer. There are two classes of proteins transport membrane one which carries specific molecules across and two is channel proteins which form narrow pore where ions can pass.

 Channel proteins also carry out passive transport where ions level spontaneously down their gradients membranes which transport proteins are important pharmacologically with two reasons. One is some drugs exploit endogenous membrane transport process to enter or exit cells. Two membrane transport proteins are major drug targets.

Answer 2

Facilitated diffusion or facilitated transport is also known as passive-mediated transport is the movement of molecules or ions across a biological membrane through transmembrane integral proteins. This process does not require chemical energy from ATP as such molecules and ions use the movement of gradient concentration for diffusion.