Lecture 13: lipids metabolism

Question 1

How does glycerol get metabolised?

Answer 1

1. Glycerol gets phosphorylated to form glycerol-3-phosphate
2. It is converted to dihydroxyacetone phosphate (DHAP) which then enters glycolysis for further metabolism

Question 2

How do fatty acids get metabolised?

Answer 2

1. Fatty acids are converted to acyl-coA
2. Carnitine acyltransferase I transfers the acyl group from acyl coA to carnitine
3. This product gets transported across the inner mitochondrial membrane
4. The acyl group is transferred to coA-SH by carnitine acyltransferase II
5. The acyl coA is degraded via beta oxidation which is a 4 step reaction. This reaction produces acetyl coA
6. The beta oxidation continues again and again until all of the products are converted to acetyl coA –> total 7 acetyl coA

Question 3

What happens during beta oxidation of odd numbered fatty acids?

Answer 3

1. The last beta oxidation step results in the production of propionyl coA
2. This is converted to succinyl coA, which enters the krebs cycle

Question 4

When are ketone bodies produced?

Answer 4

1. Intake high in lipids and low in carbohydrates
2. Diabetes not controlled well
3. Starvation
4. These conditions cause the concentration of acetyl coA to be much higher than the concentration of oxaloacetate