Glycolysis question

[DrRoyal Pains]

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I just took Achiever's Test 2 natural science section, and long story short, there is a question that says which of the following regarding cellular respiration is/are correct?
A. Substrate level phosphorylation occurs in glycolysis and the krebs cycle
B. Glycolysis may lead to fermentation or aerobic respiration
C. Each cytostolic NADH shuttling its electron to ubiqiunone of the ETC will end up producing 2 molecules of ATP
D. Each pyruvate from glycolysis is converted to Acetyl CoA before entering the Krebs Cycle
E. All of the above

Now I know everything is true, but doesn't NADH produce a net of 3 ATP, while FADH2 produces 2 ATP? Why would C be correct?

 

[ttpharm]

I just took Achiever's Test 2 natural science section, and long story short, there is a question that says which of the following regarding cellular respiration is/are correct?
A. Substrate level phosphorylation occurs in glycolysis and the krebs cycle
B. Glycolysis may lead to fermentation or aerobic respiration
C. Each cytostolic NADH shuttling its electron to ubiqiunone of the ETC will end up producing 2 molecules of ATP
D. Each pyruvate from glycolysis is converted to Acetyl CoA before entering the Krebs Cycle
E. All of the above

Now I know everything is true, but doesn't NADH produce a net of 3 ATP, while FADH2 produces 2 ATP? Why would C be correct?

It may be an error. Kaplan says NADH produces 2 ATP and FADH2 produces 3 ATP whereas other sources say otherwise.

 

[DrRoyal Pains]

Thats so stupid. Every source I have used for biology has said NADH = 3 ATP, FADH2 = 2 ATP

 

[asdfray]

C is correct.

Cytostolic NADH, meaning the ones produced during Glycolysis (during the formation of pyruvate) only obtains 2ATP/NADH, while the ones made in the mitochondria is 3ATP/NADH. Since the NADH from the cytosol cannot cross into the mitochondria, they must transfer it's electrons to ubiqiunone in the ETC and in this process, 1ATP is loss (since there's two NADH produced during glycolysis, 2 is loss in total). The NADH and the FADH2 in the mitochondria does however makes 3ATP/NADH and 2 ATP/FADH2 though (you're correct at this part). This is the reason why the ideal amount of ATP obtained for Eukaryotes from gycolysis and cellular respiration is 36 (not 38!). For prokaryotes, you obviously see it's 38ATP b/c there's no presence of membrane-bound organelles (mitochondria).


Hope that made sense. Happy studying.

 

[thejamespark]

i was wondering about that too...
NADH = 3ATP, FADH2 = 2ATP in mitochondria

I was still able to come down to that answer because I knew 100% that the first two were correct and the only answer choice was that one.
I just finished the achiever 2 and got a 19 on the PAT section.
Keyhole, TFE, my god hard...
RC is killing me. how have u been doing on the RC section of the achiever if you don't mind me asking... I'm struggling with that one. ergh

 

[DrRoyal Pains]

Ha, WOW . Thanks for the clarification.

 

[DrRoyal Pains]

I scored a 17 on the second test (I am doing them in sections). Im to the point where I a just going to keep redoing them, CDR, and godfrey just to practice. Awesome PAT!

 

[Dotoday]

NADH produces 2.5 ATP's and FADH2 produces 1.5 ATP's because of the shuttles. They are needed to shuttle molecules from cytosol to mitochondia and back. They use ATP.

Sent from my MB855 using Tapatalk

 

[asdfray]

NADH produces 2.5 ATP's and FADH2 produces 1.5 ATP's because of the shuttles. They are needed to shuttle molecules from cytosol to mitochondia and back. They use ATP.

Why would FADH2 need to be shuttled? isn't FADH reduced to FADH2 in the mitochondria? So why would there be loss of ATP?

Not questioning, just curious

 

[Blue87Fiero]

i was wondering about that too...
NADH = 3ATP, FADH2 = 2ATP in mitochondria

I was still able to come down to that answer because I knew 100% that the first two were correct and the only answer choice was that one.
I just finished the achiever 2 and got a 19 on the PAT section.
Keyhole, TFE, my god hard...
RC is killing me. how have u been doing on the RC section of the achiever if you don't mind me asking... I'm struggling with that one. ergh

RC is killing me in Achiever. I got 15's on the first two. I am taking the third one and I don't see why it would improve. I just hope I can 18 or 19 on the real thing.

 

[thejamespark]

man me too. have u been reading the article and then answering??
or did u just go straight to the questions first???
i usually read the article first but i kinda quick skimmed the article and it still took me 7 mins. -_-

 

[thejamespark]

thanks you too! don't burn yourself out! you will be do well on the PAT too!

 

[DrRoyal Pains]

man me too. have u been reading the article and then answering??
or did u just go straight to the questions first???
i usually read the article first but i kinda quick skimmed the article and it still took me 7 mins. -_-

I start out with skimming and writing keywords, then go straight to the questions and do S&D. If time is winding down, I'll just go straight to the questions, but its better to write down the keywords because I would waste a BUNCH of time skimming the article up and down. Im going to do Test 4 RC now

 

[Dotoday]

You are shuttling Hydrogens, not FAD's. Someimes you need to shuttle them to cytosol to produce NADH from NAD. Basically, if cytosol is short on H's it can borrow them from mitochondria and vise versa.

Sent from my MB855 using Tapatalk

 

[xtra333]

asdfray, I suggest you take a look at the chapter about the malate aspartate shuttle from Lehninger's principles of biochemistry if you need help understanding proton shuttles.

 

[xtra333]

or hopefully this wikipedia article might help you:
[link]http://http://en.wikipedia.org/wiki/Malate-aspartate_shuttle[/link]

 

[asdfray]

Interesting stuff, thank you for that =)

btw, does the DAT go that in depth?😀

 

[xtra333]

asdfray, to answer your question, I do not think so. I do remember, however, there was a question in achiever about how electrons are carried in cells, so NADH is an electron carrier.

The gist of that article was that NADH cannot cross the inner mitochondrial membrane, so malate does the job.