Cell Membranes

Question 1

What is the purpose of a cell surface membrane ?

Answer 1

Barrier between cell and environment

Controls substance which goes in and out of cell

Question 2

3 ways in which substances can move across cell surface membranes

Answer 2

Osmosis
Diffusion
Active transport

Question 3

Describe the structure of a membrane

Answer 3

Lipids(phospholipids)

Proteins and carbohydrates

Question 4

Name the 2 proteins in a cell surface membrane

Answer 4

Channel proteins
Carrier proteins
(Receptor proteins)

Question 5

In the fluid mosaic model what do phospholipids form

Answer 5

(Fluid) bilayer

Question 6

Protein attached to a carbohydrate?

Answer 6

Glycoprotein

Question 7

Everything in the fluid mosaic model

Answer 7

Glycoproteins 
Glycolipids
Phospholipids 
Protein 
Cholesterol 
Protein channel

Question 8

Structure of phospholipids

Answer 8

Hydrophilic head
Hydrophobic tail
Creates a phospholipid bilayer

Question 9

Importance of the centre of the phospholipid bilayer being hydrophobic

Answer 9

Membrane won’t allow water soluble substances to diffuse through it e.g ions
Small non polar molecules and water can diffuse through it

Question 10

Function of cholesterol

Answer 10

Gives the membrane stability

Question 11

What does cholesterol do to make the phospholipids pack closer together

Answer 11

Binds to the hydrophobic tail , meaning the membrane is less fluid and more rigid