Explore BrainMass

Carbon Tracking in TCA Cycle

This content was STOLEN from BrainMass.com - View the original, and get the already-completed solution here!

C14-Glucose labeled at carbon 5 enters glycolysis, is made into pyruvate, then acetyl CoA, and enters the TCA cycle. How much of the C14 will be released as CO2 during the second turn of the TCA cycle?

© BrainMass Inc. brainmass.com October 16, 2018, 8:33 pm ad1c9bdddf

Solution Preview

Get out your textbook and look at the structures as I walk you through the process of coming up with the solution.

What happens to the [14C]-Glucose labeled at carbon 5 as it goes through glycolysis?

The important point is that when the six carbon fructose-1,6-bisphosphate splits into DHAP and G3P, and that when DHAP converts into another G3P, that C5 (and C2 for that matter) both end up being the middle carbon in G3P. You can go through the individual steps on your own to confirm this, but it can be easy to remember:

C6 of glucose gets phosphorylated, right?
When it becomes fructose, the same C6 is phosphorylated.
Then, fructose gets phosphorylated on C1 too. Therefore, both ends are phosphorylated, C1 and C6.
When you get to the two G3P molecules, just remember that the carbons with the phosphates on them are the same carbons that ...

Similar Posting

TCA Cycle and Glycolysis

Hello, I was hoping someone can explain to me how to follow carbon labels (radioactive 14C) through glycolysis and TCA cycle. For example if C5 or C6 is labeled where will it end up in pyruvate or if its labeled in Oxaloacetate where it ends up after first, second round of TCA cycle etc. I'm uploading a few problems, I need a full explanation on how to follow through each cycle with details and notes. Please let me know how many credits this will require, I'm only posting 1 credit right now until someone sends me a message willing to do it!

Problem 2 & 5 in problem set 5
Problem 2 in practice exam 3

FYI, none of these are due for a grade, I have an exam Thursday

View Full Posting Details