MEH: Energy Production: Lipids

Question 1

Name the 3 classes of lipids.

Answer 1

1. Fatty acids derivatives
2. HMG acid derivatives
3. Vitamins

Question 2

Name 4 fatty acid derivatives.

Answer 2

1. Fatty aids
2. Triacylglycerols (triglycaerides)
3. Phospholipids
4. Eicosanoids

Question 3

Name 4 HMG acid derivatives.

Answer 3

1. Ketone bodies
2. Cholesterol
3. Cholesterol esters
4. Bile acid and salts

Question 4

Name the vitamins that are lipids.

Answer 4

A, D, E, K

Question 5

How is dietary triacylglycerol processed to produce energy?

Answer 5

1. It is first broken down into fatty acids and glycerol
2. It is recombined in the small intestine ad transported as TAG by lipoproteins (chylomicrons)
3. It is then sent to consumer tissues where it is oxidised to produce energy (it is sent to adipose for storage)

Question 6

When are ketone bodies formed?

Answer 6

When there are reduced glucose levels (therefore there is low NAD ) This high energy signal inhibits TCA. However, Acetyl-CoA is still building up so is diverted to ketone body production.

Question 7

Where are TAGs stored?

Answer 7

adipose tissue

Question 8

Are TAGSs hydrophobic or hydrophilic?

Answer 8

Hydrophobic

Question 9

How is stored TAG transported to consumer tissues to be oxidised?

Answer 9

albumin (remember it is hydrophobic)

Question 10

What substances activate fat mobilisation?

Answer 10

Glucagon and adrenaline

Question 11

What substance inhibits fat mobilisation?

Answer 11

Insulin

Question 12

What bits of the body does not use metabolised TAG?

Answer 12

RBC (no mitochondria)

Brain (BBB)

Question 13

What does low extracellular glucose concentration result in?

Answer 13

Fatty acids being released as alternative fuel.

Question 14

Where do stage 1 and stage 2 of dietary triacylglycerol take place?

Answer 14

1. GI tract (extracellular)

2. Mitochondria

Question 15

How are FA activated?

Answer 15

By linking it to Coenzyme A

Question 16

How is fatty acyl~CoA transported across the mitcochondiral membrane?

Answer 16

Carnitine shuttle

Question 17

What happens if the transport system that moves fatty Acyl~CoA across the mitochondria membrane has a defect?

Answer 17

A patient presents with exercise intolerance, lipid droplets are present in the muscle.

Question 18

Is more energy derived from FA oxidation or glucose oxidation?

Answer 18

FA Oxidation

Question 19

What happens to the number of carbons within the mitochondria during FA oxidation?

Answer 19

Removal of 2C

Question 20

Name the 3 ketone bodies produced in the body.

Answer 20

1. Acetoacetate
2. Acetone
   3 beta- hydroxybutyrate

Question 21

What is the normal plasma ketone body concentration?

Answer 21

<1mM

Question 22

What is the range of physiological ketosis?

Answer 22

2-10mM

Question 23

What are ketone bodies synthesis?

Answer 23

Liver mitochondria

Question 24

Statin drugs inhibit HMG-CoA Reductase. Why might patients be prescribed this?

Answer 24

HMG-CoA therefore can’t be reduced into cholesterol if their cholesterol levels are too high.

Question 25

Statin drugs inhibit HMG-CoA Reductase. Why might patients be prescribed this?

Answer 25

HMG-CoA therefore can’t be reduced into cholesterol if their cholesterol levels are too high.

Question 26

If there are increased levels of insulin (hence the patient is well fed) what does HMG-CoA produce?

Answer 26

Cholesterol

Question 27

If there are increased levels of glucagon (hence the patient is in a starvation state) what does HMG-CoA produce?

Answer 27

Ketone bodies

Question 28

Why are ketone bodies produced in response to starvation?

Answer 28

To spare glucose for the brain.

Question 29

Are ketone bodies water soluble?

Answer 29

Yes