Correct Significant Figures Feedback: Your answer 0.0786 was either rounded diff
ID: 221391 • Letter: C
Question
Correct
Significant Figures Feedback: Your answer 0.0786 was either rounded differently or used a different number of significant figures than required for this part.
Part B
Is this reaction likely to be a control point for the citric acid cycle? Why or why not?
Is this reaction likely to be a control point for the citric acid cycle? Why or why not?
No, because aconitase catalyzes an inreversible reaction
Problem 13.14
Aconitase catalyzes the reaction:
citrateisocitrate
The standard free energy change, G ', for this reaction is +6.3 kJ/mol . However, the observed free energy change (G ) for this reaction in mammalian mitochondria at 25 C is ~ 0 kJ/mol .
Part A
Calculate the ratio of [isocitrate]/[citrate] in mitochondria.
Express your answer using two significant figures.
7.9×102
Yes, because aconitase catalyzes an inreversible reaction. Yes, because citrate ion is a limiting reactant in citric acid cycle. Yes, because G is greater than 0. No, because isomerisation proceeds slow compared to the following oxydation. No, because aconitase catalyzes a freely reversible reaction.No, because aconitase catalyzes an inreversible reaction
Problem 13.14
Aconitase catalyzes the reaction:
citrateisocitrate
The standard free energy change, G ', for this reaction is +6.3 kJ/mol . However, the observed free energy change (G ) for this reaction in mammalian mitochondria at 25 C is ~ 0 kJ/mol .
Part A
Calculate the ratio of [isocitrate]/[citrate] in mitochondria.
Express your answer using two significant figures.
[isocitrate][citrate] =7.9×102
Explanation / Answer
Standard free energy change delta G0 = +6.3kJ/mole and observed free energy change delta G = 0 kJ/mole
Free energy change is positive therefore it is an endergonic reaction.
Part A: Ratio of Isocitrate/Citrate in Mitochondria
= 7.9/10-2
=.079
Part B: In the next step in Citric acid cycle, citric acid loses one molecule of water to form Cis-aconitic acid which acts as an intermediate in the isomerization of Citric acid to Isocitric acid after taking back the molecule of water. Both the reactions of this step are catalyzed by the enzyme aconitase. These reactions can be termed as reversible transformation from Citrate to Isocitrate.
Therefore, this reaction cannot be the control point in Citric acid cycle as acotinase catalyzes freely reversible reaction. Therefore option e is correct.
Standard free energy change delta G0 = +6.3kJ/mole and observed free energy change delta G = 0 kJ/mole
Free energy change is positive therefore it is an endergonic reaction.
- The reactions of EMP pathway occur in the cytoplasm and the respiratory substrate enters for the Kreb’s cycle inside the mitochondria in the form of pyruvic acid.
- Pyruvic ac id is first converted into Acetyl CoA.
- Acetyl CoA with a 4-carbon compound Oxaloacetic acid with the use of one molecule of water and as a result a 6-carbon compound Citric acid is formed.
- Therefore, this Kreb’s cycle is also called as Citric acid cycle.
Part A: Ratio of Isocitrate/Citrate in Mitochondria
= 7.9/10-2
=.079
Part B: In the next step in Citric acid cycle, citric acid loses one molecule of water to form Cis-aconitic acid which acts as an intermediate in the isomerization of Citric acid to Isocitric acid after taking back the molecule of water. Both the reactions of this step are catalyzed by the enzyme aconitase. These reactions can be termed as reversible transformation from Citrate to Isocitrate.
Therefore, this reaction cannot be the control point in Citric acid cycle as acotinase catalyzes freely reversible reaction. Therefore option e is correct.