Lipids Flashcards Preview

YEAR 1: MCD - Metabolism > Lipids > Flashcards

Flashcards in Lipids Deck (11)
Loading flashcards...
1

3 sources of fats

Diet
De novo biosynthesis
Adipocyte stores

2

Describe the process of lipid digestion

Lipase breaks down triacylglycerols
Mono, diacylglycerols, fatty acids, bile salt, cholesterol, fat-soluble lipids and lysophosphatidic acid make micelles
Enter enterocytes
Triacylglycerol reformed
Modified into chylomicrons
Enter lymphatic system

3

Describe beta oxidation

Fatty acid -> acyl coA using 2 ATPs in outer mitochondrial membrane
Enter mitochondria by carnitine shuttle
Fatty acyl coA:
oxidised to give of FADH2
Hydrolysed
Oxidised to give NADH
CoA comes and takes off 2C —> acetyl coA using B KETOTHIOLASE

4

Overall equation for breakdown of palmitate

Palmitoyl coA + 7FAD + 7 NAD+ + 7H20 + 7CoA ——> 8 acetyl coA + 7 FADH2 + 7 NADH

5

When can acetyl coA from beta oxidation enter TCA?

When beta oxidation and carbohydrate metabolism are balanced as oxaloacetate is needed

6

Which 2 enzymes are involved in biosynthesis of lipids?

Acetyl coA carboxylase
Fatty acid synthase

7

What happens if acetyl coA can’t enter TCA?

Produces:
Acetoacetate
D 3 hydroxybutyrate
Acetone

8

Describe lipogenesis

Acetyl coA + HCO3 = malonyl coA using acetyl coA carboxylase
Transfer malonyl to ACP = malonyl ACP using malonyl-coA-ACP transferase
Transfer acetyl from acetyl coA to ACP = acetyl ACP using acetyl-coA-ACP transferase
Condensation of acetyl ACP and malonyl ACP = acetoacyl ACP
Reduction using ketoreductase
Dehydration using dehydratase
Reduction using Ebola reductase

9

Differences between fat metabolism and synthesis

Synthesis = ACP and uses NADP as reducing agent, happens in ER and mitochondria
Metabolism = coA and uses NAD+ and FAD as reducing agents , happens in mitochondria

10

Lipogenesis equation

Acetyl coA + 7 malonyl coA + 14 NADP + 14H+ = palmitate + CO2 +6H2O + 8 coA + 14 NADP+

11

Diseases to do with lipid metabolism

Medium chain acyl coA dehydrogenase deficiency (MCADD)
- autosomal recessive
- part of heel prick test
- no fasting
- have a high carb diet
Primary carnitine deficiency
- autosomal recessive
- carnitine supplements given