A little biochem help before the final

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Discussion Overview

The discussion revolves around the calculation of ATP yield from the complete oxidation of glucose, specifically addressing discrepancies in the total ATP count derived from various biochemical processes, including glycolysis and the TCA cycle. Participants explore the theoretical versus net ATP yield and the implications of different assumptions in their calculations.

Discussion Character

  • Technical explanation
  • Debate/contested
  • Meta-discussion

Main Points Raised

  • One participant outlines a detailed calculation for ATP yield, arriving at a total of 32 ATP, while referencing class notes that suggest a yield of 30 ATP.
  • Another participant suggests that the discrepancy may arise from not accounting for ATP used during glycolysis, indicating that 30 ATP might represent the net yield.
  • A later reply acknowledges the mistake in the initial calculation, suggesting it was a simple oversight.
  • Some participants express confusion over abbreviations used in the discussion, questioning their relevance and understanding of the biochemical terms.
  • One participant humorously remarks on the nature of biochemistry as involving memorization of pathways and cycles, indicating a preference for mathematics over biology.

Areas of Agreement / Disagreement

Participants do not reach a consensus on the correct ATP yield, as there are multiple interpretations of the calculations and differing views on the definitions of net versus theoretical yield. The discussion remains unresolved regarding the exact source of the discrepancy in ATP counts.

Contextual Notes

Limitations include potential misunderstandings of biochemical abbreviations, assumptions about the efficiency of ATP production, and the lack of clarity on whether the discussion refers to theoretical or net ATP yields.

gravenewworld
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I was wondering if someone could explain to me where all the ATP comes from from the complete oxidation of glucose. We said in class complete oxidation yields ~30ATP. I pretty much have where all the ATP comes from so far except my math is a little off.

We said in class 2.5 ATP come from NADH when e- 's are transferred to O2.

Thus in the TCA cycle I count 4 places where NADH is given off 4x2.5=10ATP
multiply that by 2 since there are two copies of pyruvate after glycolysis for 1 glucose molecule so there are 20ATP.

In another step in the TCA cycle 1 GTP is given off so 2x1GTP=2 NTPs.
That gives 22 ATPs

In another step in TCA cycle there is 1FADH given off, which we said in class yields 1.5 ATP, so 2x1.5=3 ATP

so we have 25 ATP.

4 NTPs from glycolysis

so 29 ATPs. Finally there is 1 cytosolic NADH that is given off during glycolysis. In class we said cytosolic NADH yields 1.5 ATP. So 2x1NADH=2NADHx1.5=3ATP

For a grandtotal of

32ATP. In the handout notes my prof. gave us he said there should be 30 ATP, where did I go wrong?
 
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Did you take into account that during glycolysis ATPs are used. 30 might be the net yield of ATP.

However, I remember that maximun net yield was 38 but your prof my give you the number in term of efficiency rather than theoretical.
 
Last edited:
Ah yes that was it. Thanks for catching it. Such an easy mistake.
 
gravenewworld said:
I was wondering if someone could explain to me where all the ATP comes from from the complete oxidation of glucose. We said in class complete oxidation yields ~30ATP. I pretty much have where all the ATP comes from so far except my math is a little off.

We said in class 2.5 ATP come from NADH when e- 's are transferred to O2.

Thus in the TCA cycle I count 4 places where NADH is given off 4x2.5=10ATP
multiply that by 2 since there are two copies of pyruvate after glycolysis for 1 glucose molecule so there are 20ATP.

In another step in the TCA cycle 1 GTP is given off so 2x1GTP=2 NTPs.
That gives 22 ATPs

In another step in TCA cycle there is 1FADH given off, which we said in class yields 1.5 ATP, so 2x1.5=3 ATP

so we have 25 ATP.

4 NTPs from glycolysis

so 29 ATPs. Finally there is 1 cytosolic NADH that is given off during glycolysis. In class we said cytosolic NADH yields 1.5 ATP. So 2x1NADH=2NADHx1.5=3ATP

For a grandtotal of

32ATP. In the handout notes my prof. gave us he said there should be 30 ATP, where did I go wrong?

uh what maybe if you stopped the abriviations we could help you out?
 
Luongo said:
uh what maybe if you stopped the abriviations we could help you out?


Well, if you don't know what those abbreviations stand for, then you're not going to be able to help him anyways. :wink:
 
BoomBoom said:
Well, if you don't know what those abbreviations stand for, then you're not going to be able to help him anyways. :wink:

it looks like simple multiplication and addition with silly abbriviations is this what biochem is? lol
 
uh what maybe if you stopped the abriviations we could help you out?

1. If you don't know what ATP, TCA etc stand for, I don't think you're going to be very much help.

2. This thread is over four years old, I'm sure he has finished this class by now!
 
i think from bio 12 i remember atp is adenosinetriphosphate or something i don't know what TCA is or FAGH or NADS lol what kind of course is this? I'm glad i stuck with mathematics
 
They're all relatively basic abbreviations that most bio students learn in their first year, and yes, biochemistry basically consists of memorizing mundane chemical pathways and cycles, and knowing the abbreviations of the constituents.

Good thing I only decided to minor in bio :D
 
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Thread locked. Luongo necroposted.