1.3 Lipids

Question 1

Solubility

Answer 1

Insoluble in water

Question 2

Two forms:

Answer 2

Fats are solid at room temperature

Oils are liquid at room temperature

Question 3

Provide how much kJ?

Answer 3

37kJ/g

Question 4

Functions

Answer 4

Store energy as triglycerides (fuel reserve)

Insulation and protection

Control metabolism

Provide satiety

Question 5

Triglycerides

Answer 5

3 fatty acids + glycerol

Composed of C,H,O

Question 6

Phospholipids functions

Answer 6

Emulsifiers

Sources: egg yolk, soybeans

Question 7

Saturated

Answer 7

Every carbon (C) atom has its full quota of Hydrogen (H) atoms

Best to be kept to a minimum in the diet

Hard at room temperature

Usually derived from animal sources

Question 8

Unsaturated

Answer 8

Carbon (C) contain less than their full quota of Hydrogen (H) atoms

Results in formation of one or more double bonds

Question 9

Mono-unsaturated

Answer 9

Only one double bond between C atoms

Question 10

Polly-unsaturated

Answer 10

Two or more double bonds between C atoms

Question 11

Saturation

Answer 11

Affects the temp at which fats melt

More saturated = more liquid y

Question 12

Omega-3 Functions

Answer 12

Reducing the chances of blood clots (thrombosis)

Counteracting irregular heart beat (cardiac arrhythmia)

Lowering triglyceride levels (blood fat that is as potentially dangerous as cholesterol)

Help brain growth and function

Question 13

Omega-6

Answer 13

The regulation of…

• Blood pressure
• Blood clot formation
• Immune response

Food sources:
sunflower and safflower oils – linoleic acids
vegetable oils and meat – arachidonic acids

Question 14

Trans Fats

Answer 14

^ LDL / decrease HDL

Question 15

Cholesterol

Answer 15

Made in liver and intestines

Not readily absorbed

Question 16

Very-low-density lipoproteins (VLDL)

Answer 16

Deliver triglycerides to cells

Question 17

Low-density lipoproteins (LDL)

Answer 17

Larger particles that deposit cholesterol on the inside of walls in the arteries.

Question 18

High-density lipoproteins (HDL)

Answer 18

Smaller particles and protect against heart disease as they pick up cholesterol to the liver for removal or recycling.

Question 19

Lower Cholesterol

Answer 19

Reduced fat milk

Use mono or poly spreads rather than butter

Choose lean meat / trim fat / remove skin
Eat oily fish

Question 20

Lipid Digestion

Answer 20

Mouth and Stomach - Minimal digestion of triglycerides

Small intestine:

• Bile emulsifies fat
• Digested by pancreatic lipase
• Fats are spilt into smaller particles: 3 fatty acids and glycerol for absorption
• Absorbed into intestinal cells

Question 21

Deficiency or Excessive

Answer 21

Deficiency: (Rare in Australia)
Eczema
Skin lesions
Failure to grow

Excess:
Stored as adipose tissue -> Weight gain -> obesity
- Hypertension,

Atherosclerosis, Heart Disease, Stroke and Type II Diabetes.