studyguide3

studyguide3 - I. Citric Acid Cycle A. Acetyl CoA, the fuel...

Info iconThis preview shows pages 1–2. Sign up to view the full content.

View Full Document Right Arrow Icon
I. Citric Acid Cycle A. Acetyl CoA, the fuel for the citric acid cycle, has a high-energy thioester bond similar to that of citryl coA. Why does this bond in acetyl CoA not get hydrolyzed by citrate synthase upon entering the citric acid cycle? B. What is the net equation of the citric acid cycle? How is the energy present in acetyl CoA stored? C. What is the synthase reaction that uses acetyl CoA as a substrate to synthesize a 6 carbon intermediate? What is the difference between a synthase and a synthetase enzyme reaction? What provides the energy needed for the chemical condensation catalyzed by this citric acid cycle enzyme? D. What two enzymes in the citric acid cycle perform oxidative decarboxylation? By analogy with the pyruvate dehydrogenase reaction, show the series of reactions that are performed by the α-ketoglutarate dehydrogenase. A thiamin deficiency leads to accumulation of α-ketoglutarate in the bloodstream and a severe decrease in citric acid cycle activity. Why is this? E. The two enzymes that perform the oxidative decarboxylation reactions are regulatory points in the citric acid cycle. Describe how these enzymes are regulated. F. Which citric acid cycle enzyme is membrane associated? What redox cofactor is tightly associated with it?Show its reaction. Why is NAD+ not the cofactor in this reaction? G. Which enzyme catalyzes a substrate-level phosphorylation reaction to drive the production of a nucleotide triphosphate. Show its reaction. Considering the structure of the substrates, describe where/how is energy stored to drive the formation of an NTP? H. Two enzymes in the citric acid cycle catalyze reactions that are highly endergonic under standard biological conditions. What are they? Why do these reactions proceed in the direction that is disfavored thermodynamically? I.
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Image of page 2
This is the end of the preview. Sign up to access the rest of the document.

Page1 / 3

studyguide3 - I. Citric Acid Cycle A. Acetyl CoA, the fuel...

This preview shows document pages 1 - 2. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online