Cell membranes

Question 1

Active transport

Answer 1

The active movement of ions or polar molecules from a lower concentration to a higher concentration using a carrier protein.
This movement against the concentration gradient requires energy from ATP.

Question 2

Osmosis

Answer 2

The movement of water from an area of higher water potential to an area of low water potential, down water potential gradient across the phospholipid bilayer or via protein channels

Question 3

Simple diffusion

Answer 3

The movement of substances from an area of high concentration to an area of low concentration down a concentration gradient across a partially permeable membrane directly through the phospholipid bilayer

Question 4

Facilitated diffusion

Answer 4

movement of substances from an area of high concentration to an area of low concentration down a concentration gradient across the membrane via carrier or channel proteins

Question 5

Channel proteins

Answer 5

-act as pores in the membrane, some only allow specific ions through

-they can be gated, so the only open/close in specific circumstances

Question 6

Carrier proteins

Answer 6

Allow specific large molecules to pass through when the molecule binds to a specific site on the carrier the protein changes shape and transfers the molecules to the other side of the membrane