Fermentation vs. Glycolysis question

[riseNshine]

From TPR:
One of the ways in which fermentation differs from glycolysis is that, in fermentation:
a. glucose is oxidized
b.nad+ is regenerated
c.high-energy electrons are passed to nad+
d.atp is produced

Answer is b, which I agree with. But, the solution also states that in both fermentation and glycolysis electrons are passed to nad+. I understand how electrons are passed to nad+ to make nadh in glycolysis, but when are electrons passed to nad+ in fermentation?


Also....on an unrelated note, are strict aerobes and obligate aerobes the same thing?

Thanks!

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[dariidar]

when are electrons passed to nad+ in fermentation?

They're not. Fermentation creates NAD+ from NADH via oxidation. I'm sure the book just has a typo.

As for your other question, wikipedia says:

"-Obligate aerobes require oxygen for aerobic cellular respiration. In a process known as cellular respiration, these organisms use oxygen to oxidize substrates (for example sugars and fats) in order to obtain energy.
-Facultative anaerobes can use oxygen, but also have anaerobic methods of energy production.
-Microaerophiles are organisms that may use oxygen, but only at low concentrations.
-Aerotolerant organisms can survive in the presence of oxygen, but they are anaerobic because they do not use it as a terminal electron acceptor."

 

[Laureatebarrel]

I think fermentation includes glycolysis and the generation process of nad+

 

[gettheleadout]

I think fermentation includes glycolysis and the generation process of nad+

This is true, but the solution should have explained it better.

 

[image187]

I think fermentation includes glycolysis and the generation process of nad+

It doesnt. Fermentation is separate from glycolysis, and uses its end products to regenerate NAD+ by reducing them to other compounds. Yeast actually prefer to do this, but in humans fermentation is switched to when NAD+ cannot be regenerated in other more preferable ways (i.e. by reducing oxygen in the electron transport chain). By definition, A C and D take place during glycolysis, not fermentation.

 

[Trayshawn]

its a bad question. fermentation is sperate from glycolysis. But MCAT strategy says that the difference they were going for probably has something to do with regenerating NAD+ as thats what makes fermentation unique.

 

[gettheleadout]

It doesnt. Fermentation is separate from glycolysis, and uses its end products to regenerate NAD+ by reducing them to other compounds. Yeast actually prefer to do this, but in humans fermentation is switched to when NAD+ cannot be regenerated in other more preferable ways (i.e. by reducing oxygen in the electron transport chain). By definition, A C and D take place during glycolysis, not fermentation.

its a bad question. fermentation is sperate from glycolysis. But MCAT strategy says that the difference they were going for probably has something to do with regenerating NAD+ as thats what makes fermentation unique.

Glycolysis can be considered a part of the fermentation process:

 

[Trayshawn]

I stand corrected. Not because of the wikipedia image above - not a big fan of wikipedia.
But I did a quick search and got this from an actual college website: "The complete pathway, including Glycolysis and the re-oxidation of NADH, is called fermentation." http://www.rpi.edu/dept/bcbp/molbiochem/MBWeb/mb1/part2/glycolysis.htm

good to know. I love these Q&As. I learn so much.

 

[gettheleadout]

I stand corrected. Not because of the wikipedia image above - not a big fan of wikipedia.
But I did a quick search and got this from an actual college website: "The complete pathway, including Glycolysis and the re-oxidation of NADH, is called fermentation." http://www.rpi.edu/dept/bcbp/molbiochem/MBWeb/mb1/part2/glycolysis.htm

good to know. I love these Q&As. I learn so much.

The image was sourced on Wikipedia.