Anaerobic respiration

[Jjkwest1]

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This is from one of the questions in the princeton review bio book:

Cytochrome c:
I. is located in the inner mitochondrial membrane
II. undergoes redox reaction
III. functions in anaerobic respiration

A. I only
B. III only
C. I and II
D. I, II and III

The answer key said C. but isn't III also true? I thought that for anaerobic respiration, the ETC is still used, the only difference from aerobic respiration is that the final electron acceptor is not O2. Can someone clarify this? Thanks

 

[chem4ever]

This is from one of the questions in the princeton review bio book:

Cytochrome c:
I. is located in the inner mitochondrial membrane
II. undergoes redox reaction
III. functions in anaerobic respiration

A. I only
B. III only
C. I and II
D. I, II and III

The answer key said C. but isn't III also true? I thought that for anaerobic respiration, the ETC is still used, the only difference from aerobic respiration is that the final electron acceptor is not O2. Can someone clarify this? Thanks

For anaerobic respiration, the citric acid cycle and the ETC do not occur. The only shared pathway between anaerobic respiration and aerobic respiration is glycolysis. For anaerobic respiration, as soon as glycolysis is complete, the two pyruvate molecules undergo fermentation (producing lactic acid in muscle cells and ethanol in yeast.)

 

[Jjkwest1]

I check online and it said this:

"Anaerobic respiration is a form of respiration using electron acceptors other than oxygen. Although oxygen is not used as the final electron acceptor, the process still uses a respiratory electron transport chain; it is respiration without oxygen."

 

[ClemsonFirst]

Anaerobic respiration in humans, which I assume is what the question focuses on, only uses glycolysis and is a modified form called fermentation. Because oxygen is not present, we cannot utilize it in our electron transport chain, and we will not use any other molecule as the final electron acceptor triggering the progression of fermentation, which uses NAD+ to produce ATP and NADH to produce the byproduct lactic acid in humans.

Cytochrome C may not be present in anaerobic organisms, but I'm not entirely sure. If it is present, then you may have an argument in answering D.

For the most part, anaerobic will be in terms of humans/eukaryotes and mean using the alternate energy pathway, fermentation.

 

[chem4ever]

I check online and it said this:

"Anaerobic respiration is a form of respiration using electron acceptors other than oxygen. Although oxygen is not used as the final electron acceptor, the process still uses a respiratory electron transport chain; it is respiration without oxygen."

The electron transport chain (besides for creating a proton gradient) oxidizes NADH to NAD+ so that it can get reused in glycolysis. In anaerobic respiration, there needs to be a different electron acceptor to oxidize NADH because oxygen is not available.

Fermentation is the process by which the NADH's gets oxidized by the pyruvate and the reduced pyruvate is lactic acid. So technically, it is using an "electron transport" (I wouldn't call it a chain because I think it's only one reaction) where the "final" electron acceptor is pyruvate. But it is most definitely not using THE electron transport chain that occurs in the mitochondria which used cytochrome c.

 

[heartsavior]

cytochrome c is associated with the inner membrane, but not itself embedded in it. Cytochrome c1 and b are.

 

[heartsavior]

sorry for double post