Lipids 2 - Phospholipids + Cholesterol

Question 1

Structure of phospholipid

Answer 1

A glycerol molecule, two fatty acids + phosphate group.

(Same structure as triglycerides except one fatty acid is replaced with a phosphate group).

Question 2

Behaviour of phosphates in water

Answer 2

amphipathic so is hydrophobic and hydrophilic.

For a layer on the surface of water with heads in water and tails sticking out.

Also form micelles

Question 3

Micelles

Answer 3

Tiny balls with tails tucked away inside and the heads pointing outwards into the water.

Question 4

Phospholipid bilayer

Answer 4

A bilayer is created inside the membrane with rows of phospholipids. The tails pointing inwards and the heads outwards into the solution.

Question 5

Cholesterol

Answer 5

A type of lipid which is not made from glycerol or fatty acids

Consists of 4 carbon based rings

Small + hydrophobic

Question 6

How does cholesterol being hydrophobic mean it can do?

Answer 6

Sit in the middle of the hydrophobic part of the bilayer in the membrane.

Question 7

One Function of cholesterol

Answer 7

Regulate the fluidity of membrane preventing it from becoming to fluid or stiff.