Diffusion

Front 1

What is diffusion?

Back 1

The net movement of molecules or ions from a region where they are more highly concentrated to one where there concentration is lower

Front 2

What factors affect the rate of diffusion?

Back 2

- Concentration gradient
- Surface area
- Thickness of the exchange surface

Front 3

What is facilitated diffusion?

Back 3

Passive process involving the use of protein channels or carrier proteins in which molecules go down the concentration gradient

Front 4

What are protein channels and their function?

Back 4

Protein channels form water-filled channels across the membrane, which open only in the presence of a specific molecule
These allow water soluble ions and molecules to pass through - control entry and exit of materials

Front 5

How are carrier proteins involved in facilitated diffusion?

Back 5

Carrier proteins span the plasma membrane. When a particular molecule is present that is specific to the protein, it binds to the protein.
Causes it to change shape so the molecule is released on the inside of the membrane

Front 6

What is osmosis?

Back 6

The passage of water from a region where it has a higher water potential to a region where it has a lower water potential through a partially permeable membrane

Front 7

What is active transport?

Back 7

The movement of molecules or ions into or out of a cell from a region of lower concentration to a region of higher concentration using energy and carrier molecules

Front 8

Describe direct active transport

Back 8

Molecules or ions bind to the receptors on the carrier protein.
Inside of cell - ATP binds to the protein which splits it into ADP and a phosphate molecule
Causes protein molecule to change shape and open on the opposite side of the membrane releasing molecules to the other side of the membrane

Front 9

What is co-transport in active transport?

Back 9

When the molecule or ion is moved into the cell at the same time as a different one is being removed from it.