Components Of A Cell Membrane

Question 1

Structure of a phospholipid

Answer 1

Head is hydrophilic

Tail is hydrophobic

Question 2

How does molecules arrange themselves in phospholipids?

Answer 2

Into a bilayer- heads face out towards the water on either side of the membrane
Centre of the bilayer is hydrophobic so the membrane doesn’t allow water soluble substances through it- acts as a barrier to dissolved substances

Question 3

What is the role of cholesterol?

Answer 3

Gives the membrane stability

Question 4

What is cholesterol present?

Answer 4

In all cell membranes

Fits between the phospholipids

Question 5

Structure of cholesterol

Answer 5

Binds to the hydrophobic tails of the phospholipids, causing the, to pack more closely together, making them more rigid and less fluid

Question 6

What is the function of proteins?

Answer 6

Control what enters and leaves the cell

Question 7

What do proteins do?

Answer 7

Form channels in the membrane allowing small or charged particles through
Carrier proteins transport molecules and ions across the membrane by active transport and facilitated diffusion
Act as receptors for molecules in cell signalling when a molecule binds to the protein, a chemical reaction is triggered inside the cell

Question 8

What is the function of glycolipids and glycoproteins?

Answer 8

Act as receptors for messenger molecules

Stabilise the members by forming hydrogen bonds with surrounding water molecules

Question 9

What happens at the glycolipids and glycoproteins?

Answer 9

Sites where drugs, hormones and antibodies bind

Act as receptors for cell signalling

Question 10

What are antigens?

Answer 10

Cell surface molecules involved in the immune response

Question 11

What is the role of a phospholipid?

Answer 11

Form a barrier to dissolved substances