Active transport

Active Transport

The movement of a substance from a low conc gradient to a high conc gradient. This is done by using energy

Types of Active transport - Proton or Ion Pump

Transport proteins that require ATP/energy to do work. The protein changes shape to move molecules - this requires energy.

Co-transport

When two molecules are transported across the cell membrane together.

E.g this happens on the epithelial cells of the small intestine

Endocytosis

The process of a cells membrane stretching around a large particle in order to engulf it

What could be a reason for why cells need to be so small? - Surface Area to Volume Ratio ( SA:V)

Materials can move in and out of the cell by diffusion and active transport.

The larger the cell, the less efficient it’s ability to perform cellular transport will be. Small cells have a higher SA, lower V makes them more efficient at cell transport.

Some cells are specialized to have an increased SA:V, by having folds. This aids in the movement of materials.

Excocytosis

forcing bulky material out of the cell

Any change in shape > requires ATP/energy

adds to the cell membrane

The process of a cell spitting out a large particle by fusing a vehicle with the cell membrane