13. Exercise + questions, sequel of fatty acid metabolism

Question 1

Breakdown of triglycerides will lead to 3 fatty acids + glycerol, not .. , which is needed for ..

Answer 1

glycerol phosphate, synthesis

Question 2

What is lipolysis?

Answer 2

Breakdown (hydrolysis) of triglycerides will lead to 3 free fatty acids + glycerol

Question 3

Some lipases are inhibited by ..
High … = high …. consumption

Answer 3

Insulin. High insulin = high Ch consumption (glucose)

Question 4

What happens with beta oxidation?

Answer 4

Degradation of fatty acids

Question 5

What is the only reason that anaerobic metabolism is possible only for
glucose and not any other substrate? What product will you get with glucose anaerobic ?

Answer 5

Bc they don’t need oxidative
phosphorylation.
Lactate.
However, you need oxygen in the liver to get rid of lactate so it won’t last long-term.

Question 6

Metabolism of ethanol: yields? Where does it take place?

Answer 6

29 kj/gr (in between Ch+ pr and fatty acids)
In cytosol

Question 7

What is released per ethanol? (fun fact what does paracetamol do in terms of alcohol degradation?)

Answer 7

2 NADHc
Paracetamol blocks function of enzyme breaking down acetaldehyde (causes drunk/hangover feeling)

Question 8

With all oxidative processes there is more or less the same energetic efficiency. Why is this?

Answer 8

With all oxidative processes we always have more or less at the same level heat production > supports body temperature.

Question 9

What is the difference in ATP yield between pamitic (16:0) an linoleic (C18:2) acid?

Answer 9

Palmitic acid: -2 ATP act
C16:0, so 7 beta ox cycles. 7*4 = 28 ATP
8 acetyl-coA *10 = 80 ATP
= 108-2 = 106 ATP

Linoleic acid: -2 ATP
C18:2, so 8 beta ox cycles. 84 = 32 ATP
910 = 90 ATP
2 double bonds, 2*1.5 = -3
122 - 3 - 2 = 117 ATP

117 - 106 = 11 ATP difference

Question 10

What to take into mind when calculating oxidation of fatty acids?

Answer 10

With fatty acids, you ALWAYS need -2 ATP for activation energy before breaking down the molecule. Even with scfa of C2.
This is because fatty acid needs to be converted to cyl-CoA.

Remember, fatty acids are part of triacylglyceride (so without glyceride yet)

Question 11

What are the three SCFA? (with CX)

Answer 11

• Propionate C3
• Butyrate C4
• Acetate C2

Question 12

What is a principle and nutritional relevant difference between the three SCFA?

Answer 12

Propionate and acetate can easily be converted into Acetyl-CoA (C2). Propionate cannot. Is converted into succinyl-CoA