Facilated diffusion and active transport

what is facilitated diffusion?

Passive transport through a transport protein, moving substances from high → low concentration.

What are the two types of transport proteins?

Channel proteins and carrier proteins.

What is a channel protein?

A protein that creates a pathway through the membrane for specific molecules or ions.

What is a carrier protein?

A protein that binds to a substance and changes shape to move it across the membrane.

What is osmosis?

The movement of water across a membrane.

What are aquaporins?

Channel proteins specifically designed for water.

What is active transport?

Movement across a membrane that requires cellular energy (ATP).

Which direction does active transport move substances?

Low → high concentration, against the concentration gradient.

What does the Na⁺/K⁺ pump do?

Pumps 3 Na⁺ out and 2 K⁺ in using ATP.

What is an electrogenic/proton pump?

A pump that moves ions across the membrane to create a membrane potential (voltage).

What is cotransport?

When one substance moving down its gradient provides energy to move another substance against its gradient.

What is an example of cotransport?

H⁺ moves back into the cell and helps transport sucrose into the cell against its concentration gradient