Lipids (Biochemistry)

Question 1

What are lipids?

Answer 1

fats, oils and waxes

Question 2

What elements do they contain?

Answer 2

CArbon, Hydrogen and oxygen

Question 3

Compare oxygen count in carbs to lipids

Answer 3

oxygen content is much lower than in carbohydrates

Question 4

What is the polarity of lipids?

Answer 4

non-polar

Question 5

What is the solubility of lipids?

Answer 5

insoluble in water, soluble in organic solvents (acetone and ether (also non polar)

Question 6

What are the roles of lipids?

Answer 6

Thermal insulation
Energy Store
Buoyancy
Protection
Waterproofing
reducing water loss
source of metabolic water

Question 7

Why do lipids provide thermal insulation?

Answer 7

fat tissue has fewer capillaries

Question 8

How much energy per 1g is stored by lipids?

Answer 8

34KJ energy per 1g

Question 9

Why does fat provide buoyancy?

Answer 9

it is less dense than either muscle or bone

Question 10

how does fat provide protection?

Answer 10

fat can absorb shocks/impacts, protects organs against physical damage

Question 11

Why is lipids good for waterproofing?

Answer 11

lipid is hydrophobic so repels water

Question 12

How does lipid reduce water loss?

Answer 12

prevents desiccation/ drying out

Question 13

Why are lipids a source of metabolic water?

Answer 13

3 water molecules given off per one triglyceride formed

Question 14

How does an elephant seal use lipids?

Answer 14

as thermal insulation, buoyancy and a food store

Question 15

How does a dormouse use lipids?

Answer 15

energy store for hibernation

Question 16

how do seeds use lipids?

Answer 16

energy sore for germination/growth

Question 17

how do kidneys use lipids?

Answer 17

protection against physical damage

Question 18

How do leaves use lipids?

Answer 18

wax, reduces water loss

Question 19

How do ducks use lipids?

Answer 19

waterproofing

Question 20

What is the structure of triglycerides?

Answer 20

consists of one glycerol molecule and 3 fatty acids

Question 21

What is the structure of Glycerol?

Answer 21

Small
3 central carbon atoms
3 hydroxyl groups (OH)

Question 22

What is the structure of a fatty acid?

Answer 22

carboxyl group COOH
hydrocarbon tail/chain

Question 23

What is the difference in structure between saturated and unsaturated fatty acids?

Answer 23

Unsaturated have double carbon bonds, consist of less hydrogen atoms

Question 24

Where is Stearic acid found what is its melting point?

Answer 24

mammalian adipose tissue
69.6 deg. C

Question 25

Where is oleic acid found what is its melting point?

Answer 25

olive oil 13.4 deg. C

Question 26

What is the general formula for a Saturated fatty acid?

Answer 26

CH3(CH2)nCOOH

Question 27

What bond forms between a glycerol and a fatty acid?

Answer 27

ester bond

Question 28

How does an ester bond form?

Answer 28

by a condensation reaction

Question 29

What are the components of phopholipids?

Answer 29

1 glycerol 2 fatty acids 1 phosphate group

Question 30

What do phospholipids form? in which organelles?

Answer 30

cell surface membrane and membrane of other organelles such as endoplasmic reticulum, golgi apparatus, nuclear envelope of nucleus

Question 31

What is coronary heart disease?

Answer 31

condition in which proper circulation of blood and oxygen are not provided to the heart and surrounding tissue. Due to narrowing of blood vessels which normally supply the heart with blood and oxygen

Question 32

What contributes to heart disease?

Answer 32

a high intake of fats, especially saturated fats

Question 33

What is atherosclerosis?

Answer 33

formation of plaque and fatty build up on the artery walls, narrowing the vessels

Question 34

How are lipids transported in the body?

Answer 34

Low Density Lipoproteins (LDP) and High Density Lipoproteins transport triglycerides and cholesterol in the blood

Question 35

What are HDLs composed of?

Answer 35

mainly of proteins, only small amounts of cholesterol

Question 36

Why are HDLs often referred to as 'good' cholesterol?

Answer 36

help remove cholesterol from artery walls and transport it to the liver for removal from the body.

Question 37

What do higher HDL levels protect against?

Answer 37

coronary heart disease

Question 38

What are LDLs composed of?

Answer 38

mainly cholesterol, very little protein

Question 39

Why are LDLs often referred to as 'bad' cholesterol?

Answer 39

mostly responsible for depositing cholesterol inside arteries

Question 40

What are high levels of LDLs associated with?

Answer 40

increased risk of coronary heart disease

Question 41

How can an artheromatous plaque form?

Answer 41

early damage of protective lining of the artery means white blood cells move to the damaged area. muscle cells divide in the artery wall and there is a build-up of lipids.

Question 42

What can happen to an atheromatous plaque during exercise or stress?

Answer 42

the plaque can break. Blood enters the crack. Platelets in the blood are activated and a clot forms. Part of the clot may break off, travel to smaller vessels like arterioles and block them. Blood flow can be restricted by plaque or blocked by clot

Question 43

What is Angina?

Answer 43

affects the heart muscle, blocking of oxygen rich blood to the heart, leads to less oxygen in heart.

Question 44

What conditions put someone at greater risk of coronary heart disease?

Answer 44

Age (particularly 40+) Diabetes Gender Genetics (heredity) High blood pressure high bad cholesterol (LDL) Lack of sufficient physical activity Low good cholesterol (HDL) Menopause Obesity smoking