Lipids + fatty acids

Question 1

Why are lipids insoluble in water + why, and what are they soluble in

Answer 1

Hydrophobic–> consist hydrocarbons that form non-polar covalent bonds
soluble in organic solvents

Question 2

what are fatty acids used for

Answer 2

broken down to generate ATP

synthesise triglycerides + phospholipids

Question 3

what are triglycerides used for

Answer 3

energy storage
protection
insulation

Question 4

where are phospholipids found

Answer 4

in plasma membrane

Question 5

what are steroids used for

Answer 5

cholesterol + hormone components

Question 6

what is a fatty acid

Answer 6

long hydrocarbon chain with carboxylate group

Question 7

what is saturated fatty acid

Answer 7

NO DOUBLE BOND between carbons

solid –> hydrocarbon chain is straight so pack more tight together

Question 8

what is a unsaturated fatty acid

Answer 8

AT LEAST 1 double bonds between carbons

Question 9

what is cis unsaturated fatty acid

Answer 9

carbon atoms in double bond have H atom on same side of double bond
natural

Question 10

what is trans unsaturated fatty acid

Answer 10

carbon atoms in double bond have H atom on opposite side of double bond

Question 11

describe the characteristics of palmitic acid

Answer 11

hydrophobic
non-polar hydrocarbon chain
hydrophilic negative charged carboxylic group – associates with water
saturated

Question 12

describe the characteristics of oleic acid

Answer 12

monounsaturated
kink in chain = rigid so cannot rotate
can’t pack tightly together
liquid at room temp

Question 13

what is triglyceride made of

Answer 13

3 fatty acids

1 glycerol

Question 14

what are triglycerides used for

Answer 14

energy source
globular –> good storage
transport of lipids

Question 15

what are adipocytes + why are they important for triglycerides

Answer 15

synthesis + storage of triglycerides

adipocytes found in subcutaneous layer in abdominal cavity

Question 16

what are phospholipids made of

Answer 16

1 glycerol
2 fatty acids
1 phosphate group

Question 17

why are phospholipids called amphipathic

Answer 17

fatty acid tail = hydrophobic

phosphate head = hydrophilic

Question 18

how much of cell membrane is made of phospholipids

Answer 18

50% - in bilayer

Question 19

how much of cell membrane is made of cholesterol + what is it used for

Answer 19

20%
membrane less flexible
reduces permeability of membrane

Question 20

what are glycolipids made of

Answer 20

2 long hydrophobic hydrocarbon tails

1 or more polar sugar

Question 21

how much of cell membrane is made of glycolipids + what is their function

Answer 21

5%

protect + control function of membrane

Question 22

where else are glycolipids used in different cells

Answer 22

insulating agent in nerve cells

Question 23

what are steroids made up of + 1 example of steroid

Answer 23

4 carbon rings

Cholesterol

Question 24

what hormones are synthesised from cholesterol

Answer 24

testosterone
oestrogen
cortisol

Question 25

why are lipoproteins used in the body

Answer 25

lipids are insoluble in water so transported in plasma as lipoproteins lipoprotein carries fatty acid in blood + around body to cells

Question 26

what are apoproteins

Answer 26

protein component of lipoproteins | they interact with cellular receptors + determine metabolic rate of lipoprotein

Question 27

what are essential fatty acids

Answer 27

needed in human diet but can't be synthesised so must come from food

Question 28

what are examples of essential fatty acids + where can they be obtained

Answer 28

alpha linoleic acid + linoleic acid in forms of omega 3 + 6 | oily fish, rapeseed oil + leafy vegetables

Question 29

what are symptoms of deficiency in essential fatty acids

Answer 29

dry scaly rash decreased growth poor immunity + wound healing

Question 30

what is lipolysis + what happens after it + where does it occur

Answer 30

breakdown of triglycerides into glycerol + fatty acids + release of energy free fatty acids released into blood + circulate the body muscle liver + adipose tissue to produce ATP

Question 31

how does lipolysis breakdown a triglyceride

Answer 31

hydrolysed into glycerol + 3 fatty acids | using water + lipase

Question 32

how is lipolysis used to break down glycerol + fatty acids

Answer 32

glycerol --> glucose + enters glycolysis to make ATP | fatty acids --> acetyl coA + enters Krebs cycle

Question 33

what is lipogenesis + where does it occur

Answer 33

synthesis of lipids | liver + adipose tissue

Question 34

how is excess glucose linked to lipogenesis

Answer 34

excess glucose --> glycogen + triglycerides | in muscle + liver

Question 35

how is fructose linked to lipogenesis

Answer 35

fructose --> glycogen + triglycerides by liver linked to obesity