Molecules - Triglyceride

Question 1

Lipids

Answer 1

Group of substances soluble in alcohol not water

Include triglycerides, phospholipids, glycolipids and cholesterol

Question 2

Lipids properties

Answer 2

C,H and some O
Not polar
3 most important lipids:
- Triglyceride, phospholipids, steroids

Not polymers but have different components bonded together —— macromolecules

Question 3

Triglyceride structure

Answer 3

Glycerol and fatty acids

Fatty acids types

Some made in body

Essential fatty acids must b digested ‘complete’

Question 4

Glycerol ( part of triglyceride )

Answer 4

Alcohol 
      H     H   H
       |      |     |
H - C - C - C - H
       |      |     |
     OH  OH  OH

Question 5

Fatty acid ( part of triglyceride)

Answer 5

Carboxyl group (COOH) One end

Hydrocarbon tail

Carboxyl group ionises into H + and COO - so acidic as free H+ ions

Question 6

Fatty Acid saturated / unsaturated

Answer 6

Saturated No C = C Bond
Unsaturated C=C bond

Monounsaturated = 1 C=C bond 
More = Polyunsaturated

C=C bond gives kink as it pushes molecules apart slightly — more fluid

Animal lipids contain lots of saturated fatty acid‘s often solid at 20° C but if more unsaturated fatty acid’s melting point lower.

Question 7

Ester bond

Answer 7

Triglyceride consists of one glycerol molecule Bonded to 3 fatty acids
Condensation reaction between -COOH and -OH

Three Ester bonds

Fatty acids maybe same or different

Question 8

Function of triglycerides

Answer 8

Energy source - hydrolyse Ester bonds —— fatty acid and glycerol broken down to carbon dioxide and water

Energy store- Indissoluble
Fat stored in adipose cells

Insulation- adipose cells - Blubber —- heat insulator

Buoyancy- fat less dense than water used by aquatic animals to stay afloat

Protection- Fat around delicate organs I.e. kidneys