Tca Cycle Chemistry Paper (Page 2 of 4) in pdf

Tca Cycle Chemistry Paper Page 2

7. At what point in the citric acid cycle do the methyl carbon from acetyl-CoA and the carbonyl

carbon from oxaloacetate become chemically equivalent?

8. The citric acid cycle is frequently described as the major pathway of aerobic catabolism,

which means that it is an oxygen-dependent degradative process. However, none of the reactions

of the cycle directly involves oxygen as a reactant. Why is the pathway oxygen-dependent?

9. There are a number of human diseases in which one of the enzymes necessary for the

synthesis or breakdown of glycogen is defective. There are few, if any, humans with defects in

the enzymes of the citric acid cycle. Explain this observation in terms of the role of the citric

acid cycle.

10. In 1935, Szent-Gyorgi showed that the production of CO

in an extract of muscle increased

when succinate was added. For every mole of succinate added, many extra moles of CO2 were

produced. Explain this effect in terms of the known catabolic pathways.

11. You are in charge of designing a new bacterium that will derive all of its ATP from sunlight

by photosynthesis. Will you put the enzymes of the citric acid cycle in this organism? Briefly

explain why or why not?

Tca Cycle Chemistry Paper Page 2