MEH: Energy Production: Lipids Flashcards
Name the 3 classes of lipids.
- Fatty acids derivatives
- HMG acid derivatives
- Vitamins
Name 4 fatty acid derivatives.
- Fatty aids
- Triacylglycerols (triglycaerides)
- Phospholipids
- Eicosanoids
Name 4 HMG acid derivatives.
- Ketone bodies
- Cholesterol
- Cholesterol esters
- Bile acid and salts
Name the vitamins that are lipids.
A, D, E, K
How is dietary triacylglycerol processed to produce energy?
- It is first broken down into fatty acids and glycerol
- It is recombined in the small intestine ad transported as TAG by lipoproteins (chylomicrons)
- It is then sent to consumer tissues where it is oxidised to produce energy (it is sent to adipose for storage)
When are ketone bodies formed?
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.
Where are TAGs stored?
adipose tissue
Are TAGSs hydrophobic or hydrophilic?
Hydrophobic
How is stored TAG transported to consumer tissues to be oxidised?
albumin (remember it is hydrophobic)
What substances activate fat mobilisation?
Glucagon and adrenaline
What substance inhibits fat mobilisation?
Insulin
What bits of the body does not use metabolised TAG?
RBC (no mitochondria)
Brain (BBB)
What does low extracellular glucose concentration result in?
Fatty acids being released as alternative fuel.
Where do stage 1 and stage 2 of dietary triacylglycerol take place?
- GI tract (extracellular)
2. Mitochondria
How are FA activated?
By linking it to Coenzyme A
How is fatty acyl~CoA transported across the mitcochondiral membrane?
Carnitine shuttle
What happens if the transport system that moves fatty Acyl~CoA across the mitochondria membrane has a defect?
A patient presents with exercise intolerance, lipid droplets are present in the muscle.
Is more energy derived from FA oxidation or glucose oxidation?
FA Oxidation
What happens to the number of carbons within the mitochondria during FA oxidation?
Removal of 2C
Name the 3 ketone bodies produced in the body.
- Acetoacetate
- Acetone
3 beta- hydroxybutyrate
What is the normal plasma ketone body concentration?
<1mM
What is the range of physiological ketosis?
2-10mM
What are ketone bodies synthesis?
Liver mitochondria
Statin drugs inhibit HMG-CoA Reductase. Why might patients be prescribed this?
HMG-CoA therefore can’t be reduced into cholesterol if their cholesterol levels are too high.
Statin drugs inhibit HMG-CoA Reductase. Why might patients be prescribed this?
HMG-CoA therefore can’t be reduced into cholesterol if their cholesterol levels are too high.
If there are increased levels of insulin (hence the patient is well fed) what does HMG-CoA produce?
Cholesterol
If there are increased levels of glucagon (hence the patient is in a starvation state) what does HMG-CoA produce?
Ketone bodies
Why are ketone bodies produced in response to starvation?
To spare glucose for the brain.
Are ketone bodies water soluble?
Yes
