Lipids

Question 1

Triglyceride

Answer 1

Made up of one glycerol molecule and three fatty acids joined together by ester bonds

Question 2

Phospholipids

Answer 2

Structure is similar to triglycerides except one fatty acid is replaced by a phosphate
Phosphate heads are hydrophilic
Tails are hydrophobic

Question 3

Saturated lipids

Answer 3

Has only single carbon-carbon bonds
:. Has maximum possible number of hydrogen atoms

Question 4

Unsaturated lipids

Answer 4

Has double carbon=carbon bond(s),
That form a kink so the molecules do not align uniformly preventing the molecule from being tightly packed
:. Unsaturated lipids such as oils are liquid at room temperature

Question 5

Roles of triglycerides

Answer 5

Energy reserve - lipids contain more carbon-hydrogen bonds than carbohydrates,
Thermal insulation - lipids insulate against heat loss or heat gain
Produces metabolic water - this is released from the body’s chemical reactions when triglycerides are oxidised

Question 6

Roles of phospholipids

Answer 6

Structural - in biological membranes
Electrical insulation

Question 7

Test for lipids

Answer 7

Add ethanol to solution and shake
Add cold water and shake
Cloudy white emulsion should form

Question 8

Diet high in saturated fats

Answer 8

Build up of low-density lipoproteins (LDL0
Atheroma gets deposited into coronary arteries restricting blood flow
Lack of oxygen to heart can result in angina and so a heart attack occurs

Question 9

Diet high in unsaturated fats

Answer 9

Body makes more high-density lipoproteins (HDL)
That carry harmful fats away to the liver for disposal
Lowering the risk of cardio-vascular and coronary heart disease