Lipids

Question 1

What are 3 defining characteristics of lipids

Answer 1

1) Insoluble in water
2) soluble in organic compounds
3) Have multiple non-polar C-H bonds

Question 2

What are the main types of lipids?

Answer 2

1) Triglycerides (fats and oils)
2) Steroids
3) phospholipids
4) Waxes

Question 3

What type of reaction needs to occur between the glycerol molecules and the fatty acids to form a triglyceride?

Answer 3

Dehydration synthesis

Question 4

Define the following fats:

• Saturated
• Monounsaturated
• Polyunsaturated

Answer 4

• Saturated: has as many hydrogen atoms as possible attached to the carbon backbone of the fatty acid tail.
• Monounsaturated: has one double bond in the carbon chain of the fatty acid tail
• Polyunsaturated: has multiple double carbon - carbon bonds in the fatty acid tail

Question 5

List 4 essential roles of fats in living organisms

Answer 5

1) Energy storage (fat has twice the energy of carbohydrates)
2) Insulation
3) Absorption of fat-soluble vitamins (E, D, K)
4) Needed to form cell membranes (Phospholipids)

Question 6

How do steroids differ structurally from other lipids?

Answer 6

They form rings rather than linear chains

Question 7

What is the formula and structure of glycerol

MUST BE MEMORISED FOR GAMSAT

Answer 7

C3 H8 O3

      H  H    H
       l    l     l
H - C - C - C - H
       l     l     l 
    HO HO HO

Question 8

What are the components of a triglyceride?

Answer 8

Triglycerides are made from a glycerol backbone with 3 fatty acid tails bonded to each of the hydroxyl groups of the glycerol molecule via dehydration synthesis.