Membrane Proteins

Question 1

Cholesterol

Answer 1

Regulates fluidity/flexibility and adds stability to membrane. Positioned between phospholipids in bi-layer

Question 2

Glycolipids

Answer 2

Lipids are attached to carbohydrates chain. recognition sites and antigens.Recognised by the immune system.anti gens for cell-cell recognition.

Question 3

Channel protein

Answer 3

Provided hydrophilic channel, allowing small polar molecules and ions to pass passively through a membrane. Movement is DOWN a concentration gradients

Question 4

Carrier protein

Answer 4

Can change shape in order to transport molecules across a membrane. Can be used in both passive and active transport

Question 5

Glycoprotein

Answer 5

Intrinsic protein with carbohydrate chains attached. Play a role in cell adhesion in certain tissues. Important for cell communication act as receptors for chemical signals

Question 6

Fluid mosaic model

Answer 6

Phospholipids are “fluid”, they are free to move within the layer leading to membrane flexibility.

The proteins are variable in size and shape and are scattered randomly throughout the membrane like tiles with a mosaic

Question 7

Phospholipids

Answer 7

Composed of glycerol backbone attached on one end to two fatty acids and the other end has the esterified phosphoric that is modified by an alcohol group

Question 8

Intrinsic

Answer 8

Transmembrane - embedded in both layers of the membrane.

Examples, channel protein , carrier protein and glycoproteins

Question 9

Transmembrane

Answer 9

Transmembrane proteins span the entire plasma membrane. Transmembrane proteins are found in all types of biological membranes.

Question 10

Extrinsic

Answer 10

Found in surface/present on 1 side of the bi-layer.

Usually functions as enzymes and catalyse reactions e.g hormones