lecture 10 - lipid metabolism

Question 1

what are the different classifications of lipids?

Answer 1

simple (fatty acids), compound (triacylglycerols) and derived (steroids)

Question 2

what is a fatty acid comprised of?

Answer 2

a long chain of carbon atoms

Question 3

what is classified as a short chain fatty acid?

Answer 3

less than 8 carbons - found in milk fat

Question 4

what is classified as a medium chain fatty acid?

Answer 4

8-14 carbons, found in milk fat and coconut

Question 5

what is classified as a long chain fatty acid?

Answer 5

more than 14 carbons, makes up most of our diets

Question 6

what is a saturated fatty acid?

Answer 6

no double carbon bonds

Question 7

what does an unsaturated fatty acid have?

Answer 7

at least one double carbon bond - less tightly packed

Question 8

what is a mono unsaturated fat (MUFA)?

Answer 8

one double carbon bond

Question 9

what is a poly unsaturated fat (PUFA)?

Answer 9

more than one double carbon bond

Question 10

where are lipids stored?

Answer 10

in adipose tissues as triglycerides

Question 11

what is lipolysis?

Answer 11

break down of fat which takes place in fasting conditions
- takes place in adipose tissue

Question 12

what hormone activates lipolysis at rest?

Answer 12

glucagon

Question 13

what is the main hormone that activates lipolysis during exercise?

Answer 13

adrenaline

Question 14

what is the primary regulator to how fast fatty acids are broken down?

Answer 14

HSL

Question 15

what regulates the num of transport proteins?

Answer 15

high fat diet

Question 16

what is beta oxidation?

Answer 16

generates energy, cuts off carbon atoms from the chain and changes it into acetyl coA - happens in the aerobic energy system

Question 17

what needs to happen to a fatty acid before it is used for beta oxidation?

Answer 17

transported across the membrane

Question 18

what does it mean relating to beta oxidation if the fatty acid is longer?

Answer 18

the more cycles it has to undergo

Question 19

during beta oxidation what is removed at every step?

Answer 19

an acetyl coA

Question 20

what is decreased during exercise to allow beta oxidation to occur?

Answer 20

malonyl coA

Question 21

what is the amount of acetyl coa dependent on?

Answer 21

carb availability

Question 22

is fatty acid synthesis reversible?

Answer 22

no - fatty acids can’t be converted to glucose but glucose can be converted to fatty acids

Question 23

during fatty acid synthesis what happens?

Answer 23

more acetyl coa is transported so that they can combine to create 4 carbon molecules

Question 24

is a fatty acid synthesis allosteric regulation?

Answer 24

no - there is a high degree of hormonal control which happens at a much slower rate

Question 25

what is this reaction activated by?

Answer 25

insulin

Question 26

what is this reaction inhibited by?

Answer 26

glucagon

Question 27

what does ACC do?

Answer 27

dictates the speed of fatty acid synthesis

Question 28

what is a ketone body?

Answer 28

3 diff molecules which are classified – they are only produced in small quantities, useful when glucose is low – can be used as an alternative fuel source

Question 29

what is a ketogenic diet?

Answer 29

low protein, high fat – ketosis – produce so many ketone bodies to act as an alternative fuel source to glucose so that we rely less on glucose – can produce weight loss The longer the fast goes on for the higher the number of ketone bodies Can be dangerous conditions e.g. diabetes – excessively high num of ketone bodies