Topic 7: Energy Production: Lipids Flashcards
1
Q
What are the three classes of lipids?
A
- Fatty acid derivatives
- Hydroxy-methyl-glutaric acid derivatives
- Vitamins
2
Q
What are some fatty acid derivatives?
A
Fatty acids
Triacylglycerols
Phospholipids
Eicosanoids
3
Q
What are some hydroxy-methyl-glutamic acid derivatives?
A
Ketone bodies
Cholesterol
Cholesterol esters
Bile acids and salts
4
Q
What are some lipid soluble vitamins?
A
A, D E and K
5
Q
How is dietary triacylglycerol processed to produce energy?
A
- Hydrolysed by pancreatic lipase in small intestine to release glycerol and fatty acids (using bile salts and colipase)
- Glycerol metabolized in liver using glycerol kinase into glycerol phosphate, which is then oxidized to dihydroxyacetone phosphate which then goes through glycolysis to produce energy
- Adipose tissue triacylglycerols hydrolyse by hormone-sensitive lipase to release fatty acids and glycerol (lipolysis)
6
Q
How are ketone bodies formed?
A
Synthesised in liver mitochondria by lyase and reductase enzymes controlled by the insulin/glucagon ratio
7
Q
When are ketone bodies formed?
A
Starvation and in untreated type 1 diabetes
8
Q
Why are ketone bodies formed?
A
They are important fuel molecules that can be used by all tissues containing mitochondria including the CNS
9
Q
What is the central role of acetyl~CoA in metabolism?
A
- Produced by catabolism of fatty acids, sugars, alcohol and certain amino acids
- Oxidized via stage 3 of catabolism
- Important intermediate in lipid biosynthesis
