Question

List and describe the three different types of membrane transport that occur in a cell (not including bulk transport). Provide one example of each.

Answer 1

different types of membrane transport that occur in a cell are =

1] Passive transport - passive transport involves the movement of materials along a concentration gradient ( High concentration to low conc.)

Because materials are moving down a conc.gradient,it does not require expenditure of energy.

there are 3 main types of passive transport.

a] Simple diffusion- in this diffusion ,small noncharged molecules or lipid soluble molecules pass between the phospholipids to enter or leave the cell,moving from areas of high conc.to areas of low concentration i.e. they move down their conc.gradient.

example- Oxygen and carbon dioxide and most lipid enter & leave cells by simple diffusion.

B] Osmosis= is a type of simple diffusion in which water molecules diffuse through a selectively permeable membrane from areas of high water concentration to areas of lower water conc.

example- movement of water molecules

C] Facilitated diffusion-substances move into or out of cells down their concentration gradient through protein channels in the cell membrane.

example- charged or polar molecules i.e.ions,sucrose atc.

2] Active transport- Involves the movement of materials against a concentration gradient i.e.low to high.

because materials are moving against a gradient ,it requires the expenditure of energy.