Module 2

Cell Mediated Transport

Movement of molecules across a cell membrane by transport proteins.

Diffusion

Passive process that relies on the concentration gradient for molecule movement.

Primary Active Transport

Uses ATP as an energy source to pump molecules against their concentration gradient.

Secondary Active Transport

Uses the concentration gradient of one molecule to move a second molecule against its gradient.

Transport Proteins

Proteins that assist in the movement of substances across a cell membrane.

Channel

A type of transport protein that creates open, water-filled pores for molecule passage.

Gated Channel

A channel that opens and closes under various conditions to regulate molecule flow.

Carrier

A transport protein that binds to a substrate and undergoes a conformational change to move it across the membrane.

ATPase Pump

A transport protein that uses ATP to trigger conformational changes for substrate movement.

Uniporter

A transport protein that moves one type of molecule across the membrane.

Cotransporter

A transport protein that moves more than one type of molecule per cycle.

Symporter

A cotransporter that moves molecules in the same direction.

Antiporter

A cotransporter that moves molecules in opposite directions.

Unidirectional

A transport process that only works in one direction.

Bidirectional

A transport process that can work in either direction.

Competition for Specificity

The phenomenon where multiple molecules compete for the same active site on transport proteins.

Concentration Gradient

The difference in concentration of a substance across a space, affecting transport processes.

Na+/K+ Pump

A primary active transport mechanism that moves 2 K+ ions into the cell and 3 Na+ ions out using 1 ATP.

Conformational Change

The alteration in the shape of a transport protein that facilitates substrate movement.

Establishing Concentration Gradient

The process that must occur via primary active transport to enable secondary active transport.