Lipids

Question 1

Lipids

Answer 1

Group of substances soluble in alcohol but not water (because non-polar substance), smaller amounts of oxygen

Question 2

Triglyceride is made of

Answer 2

Glycerol and 3 fatty acids

Question 3

What does a C=C do?

Answer 3

Make unsaturated
Change shape of chain
Kink push molecules apart so more fluid so lower melting point

Question 4

Carboxyl group

Answer 4

-COOH

Question 5

Carboxyl ionises into

Answer 5

H+ and -COO-

Question 6

Triglyceride functions

Answer 6

Energy source
energy store 
Insulation
Buoyancy
Protection

Question 7

Why are triglycerides good energy stores/sources?

Answer 7

Less oxygen atoms so higher proportion of hydrogen atoms so release more energy
Insoluble in water so doesn’t affect water potential

Question 8

Phospholipid structure/function

Answer 8

Same as triglyceride but 1 fatty acid replaced by phosphate group

Selectively permeable, let’s small non-polar molecules through

Question 9

Cholesterol properties

Answer 9

Small hydrophobic

Steroid alcohol

Question 10

Cholesterol structure

Answer 10

4 carbon based rings,
Isoprene units
Not made from glycerol or fatty acids

Question 11

Cholesterol is small and hydrophobic so…

Answer 11

Can pass through hydrophobic part of membrane

Sit in bilayer to regulate fluidity of membrane