Question

T/F : Lactic acid fermentation starts when all the co-enzyme A is used up

Answer 1

how are they related..

Answer 2

I think the lactate starts to build up when the oxygen is low - eg in a muscle during extreme exercise

Answer 3

i know that too...then? i sstill dont get it

Answer 4

Sorry - I didn't know what you wanted to know. Acetyl Coenzyme A is how carbon from fatty acids get into the citric acid cycle; the oxidation of the carbon contributes to energy production in the cell

Answer 5

but lactate is when oxygen is used up
acetyl coA is generating carbon from fatty acid
so...they dont really related?

Answer 6

I think it might go like this - if you are a muscle cell and there's plenty of oxygen then you can run on fat or sugar (so the pyruvate can come from either fat or glucose via acetyl coA). The acetyl co A can be used up by the TCA cycle, which produces NADH from NAD+. This NADH can be used in oxidative phosphorylation to produce many molecules of ATP per molecule of acetyl coA if oxygen is present. If there's not enough oxygen the cell can make energy from the TCA cycle but this only produces 2 molecules of ATP. The cell builds up lactate which is dealt with by the liver if the organism can get a rest - this is called getting rid of the "oxygen debt".

I hope this makes things clearer - if not let me know and I'll try to answer any specific questions you might have

Answer 7

So is it more oxygen = more cellular respiration
when coA is used up means no more oxygen, and lactic acid builds
is it like that?

Answer 8

I don't think the cell runs out of acetyl co A unless there is no sugar, fat or protein to be broken down. If there is no oxygen then there's no oxidative phosphorylation in the mitochondria so energy comes from glycolysis and there's a build up of lactate. This is because the lack of oxygen means the carbon in acetyl coA can't go into the TCA cycle. Instead, the energy come from glucose breakdown to pyruvate and fermentation. Fermentation in animals is the conversion of pyruvate to lactate and NADH.

Answer 9

ok
so if acetyl coa is used up = no glucose available
no glucose = build in lactic acid


ohh i get it now!! so the answer is true

Answer 10

Sorry to burst your balloon but it's actually if there's not enough oxygen then glucose is broken down to pyruvate and converted to lactate. This can go on for a short while but there's a build up if more lactate is produced by the muscles than the liver can clear. This is known as an oxygen debt. I hope this clears things up a bit, best wishes