May be stupid BIO question

[299678]

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I was always wondering why glycolysis is anaerobic?
the book said the glycolysis does not involve the intervention of molecular oxygen, so called anaerobic, but

when we have oxygen, it undergo glycolysis
when we have a oxygen deficiency, it undergo fermentation, then glycolysis should be called aerobic? hehe

Please explain this for me

thank you

 

[SmB27]

Glycolysis will operate in both the presence and absence of oxygen; it neither requires oxygen, nor is poisoned by it.
Fermentation is anaerobic respiration. It includes the process of glycolysis, the reduction of pyruvate to ethanol or lactic acid, and the oxidation of the NADH back to the NAD+.
Aerobic respiration requires oxygen. If oxygen is present in a cell that is capable of aerobic respiration, the products of glycolysis (pyruvate and NADH) will move into the matrix of a mitochondrion. Once inside, pyruvate is converted to acetyl CoA.

So, when no O2 is available, the cell will convert pyruvate to lactic acid, or ethanol depending on the organism. When O2 is available pyruvate will be converted to acetyl CoA then enter into the Citric acid cycle.

So because glycolysis is part of fermentation and aerobic respiration it is both aerobic and anaerobic.

I am going based off my understanding of class lectures, so I hope I covered it correctly.
(sorry if there are any mistakes)

 

[jay47]

I was always wondering why glycolysis is anaerobic?
the book said the glycolysis does not involve the intervention of molecular oxygen, so called anaerobic, but

when we have oxygen, it undergo glycolysis
when we have a oxygen deficiency, it undergo fermentation, then glycolysis should be called aerobic? hehe

Please explain this for me

thank you

Glycolysis must happen for it to go through fermentation. The product of glycolysis is used in fermentation, so it DOES occur in both anaerobic and aerobic conditions.

 

[azar87]

glycolysis my friend is anaerobic because there is no actual use for oxygen in this cycle. However the key point is noting that when oxygen is not present fermentation will occur.

 

[jj007]

The best way to understand fermentation is the following:

Glycolysis generates ATP and NADH. NADH usually get transported into the ETC to generate ATP. However, since no oxygen is present, ETC does not work. Hence there will be an accumulation of NADH. Therefore we need a mechanism to oxidize NADH back to NAD+; hence fermentation.

 

[AmpedUp]

Definitely not a stupid question. Some Biology teachers don't do a good job making metabolism a clear and easy to understand subject. This question you've asked has taken me a few years to process it correctly, mainly nurtured and developed in upper level classes. However, just like someone mentioned, Glycolysis is an anaerobic process because it simply doesn't utilize oxygen...the main goal of glycolysis is to push reaction into cellular respiration or fermentation pathways.

 

[kokokaware3]

here are my 2 cents. to make it easier for you to understand it

1st > you have to know that glycolysis is anarobic ( which means it doesnt need oxygen to go on, so it can go on with or without the presence of oxygen)

2nd > here is the trick :: now we have the products of glycolysis, which is Puryvate. watch this out lol >> if oxygen is present pyruvate which is the product of glycolysis will go to kreb cycle then ETC (electron transport chain) this is called oxadative phophorylation.

but if oxygen is not present pyruvate will go Fermentation ( this is usually happens in muscles, producing lactic acid)

i hope that made it clear