Krebs Cycle Question- HELP!!!

[DonExodus]

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This question has been bugging me forever.

Is the conversion of pyruvate to acetyl-CoA part of the Krebs cycle or not???
One book says it links the two, and another has it listed as step 1 of the Krebs cycle.

I ask because this produces CO2 and NADH. If Im asked a question regarding the products of the Krebs cycle, should I include those CO2s and NADHs?



Also wondering if we need to know the intermediates (quinone, Fc, etc) and their orders in the electron transport chain.

Finally, with the Calvin Cycle. It takes 3CO2 to make a G3P. Does 1 turn produce 1 G3P and use 3CO2? (Hence 2 turns to make a glucose)
Or, do we count it as a turn based on the entry of 1 CO2? (6 turns to make glucose).
Topscore had it as the latter, but that makes no sense, since you need 3CO2 to make a G3P.

Thoughts?

 

[GoDucks69]

This question has been bugging me forever.

Is the conversion of pyruvate to acetyl-CoA part of the Krebs cycle or not???
One book says it links the two, and another has it listed as step 1 of the Krebs cycle.

I ask because this produces CO2 and NADH. If Im asked a question regarding the products of the Krebs cycle, should I include those CO2s and NADHs?



Also wondering if we need to know the intermediates (quinone, Fc, etc) and their orders in the electron transport chain.

Finally, with the Calvin Cycle. It takes 3CO2 to make a G3P. Does 1 turn produce 1 G3P and use 3CO2? (Hence 2 turns to make a glucose)
Or, do we count it as a turn based on the entry of 1 CO2? (6 turns to make glucose).
Topscore had it as the latter, but that makes no sense, since you need 3CO2 to make a G3P.

Thoughts?

Yes include pyruvate to acetyl-CoA as part of the krebs cycle. It is outside of the circle but it feeds into the cycle and is definately a part of it.

 

[KingChris]

This question has been bugging me forever.

Is the conversion of pyruvate to acetyl-CoA part of the Krebs cycle or not???
One book says it links the two, and another has it listed as step 1 of the Krebs cycle.

I ask because this produces CO2 and NADH. If Im asked a question regarding the products of the Krebs cycle, should I include those CO2s and NADHs?



Also wondering if we need to know the intermediates (quinone, Fc, etc) and their orders in the electron transport chain.

Finally, with the Calvin Cycle. It takes 3CO2 to make a G3P. Does 1 turn produce 1 G3P and use 3CO2? (Hence 2 turns to make a glucose)
Or, do we count it as a turn based on the entry of 1 CO2? (6 turns to make glucose).
Topscore had it as the latter, but that makes no sense, since you need 3CO2 to make a G3P.

Thoughts?

no, decarboxylation is an intermediate step and is not considered part of the krebs cycle. Know that quinone and Fc are involved in etc but that's it. and for calvin cycle, I turn produces NO g3p and uses 1 co2. 3 turns is necessary to produce 1 g3p. remember that every turn is fixing another molecule of co2, so the amount of co2 is always proportional to the number of turns in the cycle.

 

[thehipster]

no, decarboxylation is an intermediate step and is not considered part of the krebs cycle. Know that quinone and Fc are involved in etc but that's it. and for calvin cycle, I turn produces NO g3p and uses 1 co2. 3 turns is necessary to produce 1 g3p. remember that every turn is fixing another molecule of co2, so the amount of co2 is always proportional to the number of turns in the cycle.

Yeah, this is the right answer

 

[joonkimdds]

Is the conversion of pyruvate to acetyl-CoA part of the Krebs cycle or not???
One book says it links the two, and another has it listed as step 1 of the Krebs cycle.

Think of 4 different stages.
1st stage = glycolysis
Cellular respiration(2nd,3rd,and 4th steps) and they are
2nd = pyruvate decarboxylation
3rd = Krebs cycle(citric acid cycle)
4th = electron transport chain

I ask because this produces CO2 and NADH. If Im asked a question regarding the products of the Krebs cycle, should I include those CO2s and NADHs?

1 cycle of Krebs cycle(considering just 1 pyruvate acid)
is 1ATP, 3NADH, and 1FADH2

2nd stage has
2pyruvic acid + 2 Coenzyme A + 2NAD+ ==>2acetyle CoA +2CO2 + 2NADH
therefore u don't have to include those CO2 and NADHs

Also wondering if we need to know the intermediates (quinone, Fc, etc) and their orders in the electron transport chain.

not sure

Finally, with the Calvin Cycle. It takes 3CO2 to make a G3P. Does 1 turn produce 1 G3P and use 3CO2? (Hence 2 turns to make a glucose)
Or, do we count it as a turn based on the entry of 1 CO2? (6 turns to make glucose).
Topscore had it as the latter, but that makes no sense, since you need 3CO2 to make a G3P.

Thoughts?

easy way to remember
CO2 combines with RuBP per cycle
so in 3rd cycle
3 of CO2 combines with 3of RuBP
meaning
(3 x 1c) + (3 x 5c) = 18c
seperate 18C into 3(since 3 cycle) = 6C, 6C, 6C
and that's 6PGA (PGA=3C)

*6 of ATP and 6 of NADPH from light reaction makes 6 of PGA into 6 of PGAL.
*2 ATP and 2 NADPH for each CO2(i used 3CO2, remember?)
*only 1 PGAL is released and 5PGAL recycle by becoming 3RuBP with help of 3ATP[how? because PGAL has 3C so 5PGAL = 15C = 3RuBP since RuBP=5C. anyway these 3RuBP meet 3CO2 and the cycle repeats!!!]
*since 3 cycle release 1PGAL, 6cycle release 2PGAl which is glucose!!!
[2PGAL = 2 x 3C = 6C = glucose!!!]

 

[akdental]

wooh...thanks for breakin it down like that joon. 👍

 

[DonExodus]

I understand it, and the loss/gains of carbons. My issue was just the terminology heh. Adding 1C gives nothing, you need 3. Its not like the cycle makes G3P one carbon atom at a time, and the products are joined...