Ocr Biology (Cell Membranes)

Front 1

Describe the 3 functions of the membrane at the surface of the cell.

Back 1

>Separating cell contents from the outside environment
>Controls which substances enter and leave the cell
>Cell recognition and signalling

Front 2

Describe the 3 functions of the membrane within the cell.

Back 2

>Divide cell into compartments making different functions more efficient
>Can form vesicles
>Control which substances enter and leave the organelle.

Front 3

Describe the 'fluid mosaic' structure.

Back 3

>Phospholipid molecules form a continuous fluid bilayer
>Various protein molecules are scattered through the bilayer some can move around
>Glycoproteins (protein molecules have a carbohydrate part attached)
>Glycolipids (phospholipid molecules have a carbohydrate part attached)
>Cholesterol

Front 4

Describe the role of cholesterol in the cell membrane.

Back 4

Cholesterol molecules fit between phospholipid tails to make the membrane more rigid/more complete so water molecules and ions cannot pass easily through the membrane.

Front 5

Describe the role of phospholipids in the cell membrane.

Back 5

Front 6

Describe the role of glycolipids and glycoproteins in the cell membrane.

Back 6

>Cell signalling and recognition
>Glycoproteins can bind cells together in tissues.
>Some receptor sites allow hormones to bind with the cell which causes the cell to respond in some way.

Front 7

Outline the effects of changing temperature on membrane structure and permeability.

Back 7

Increase in temperature gives molecules more kinetic energy so they move faster. This increased movements of phospholipids makes membranes more permeable.

Front 8

Describe the role of channel proteins in the cell membrane.

Back 8

Allows the movement of molecules that are usually too large and too hydrophylic to cross the membrane.

Front 9

Describe the role of carrier proteins in the cell membrane.

Back 9

Actively moves some substances across membrane using ATP.

Front 10

Explain the term 'cell signalling'.

Back 10

One cell releases a messenger molecule, which travels to another cell where it binds to a receptor on the target cell membrane because the two have complimentary shapes, causing the target cell to respond in some way.