Homework Questions 1)The pyruvate dehydrogenase complex utilizes multiple different cofactors. List each cofactor and where it is found in the enzyme and explain its role in the overall mechanism. 2)

Homework Questions

1)The pyruvate dehydrogenase complex utilizes multiple different cofactors. List each cofactor and where it is found in the enzyme and explain its role in the overall mechanism.

2)There is growing evidence that oxidative phosphorylation complexes I, II, III, and IV may be connected into a supercomplex. What might be the advantage of having all four complexes within a supercomplex?

3)During gluconeogenesis, the conversion of Pyruvate to PEP occurs via shuttling intermediates into and out of the mitochondria. Describe the steps of this pathway and explain why this pathway has to be shuttled through an additional organelle and the benefits of doing it this way.

4)Depending upon the environmental conditions (aerobic or anaerobic) different organisms do different things with pyruvate at the end of glycolysis. Describe in detail the different things organisms do with pyruvate and why each of these different fates is advantageous to the organism.

5)You decide to use the same biomolecules that are found on Earth in this other planet. Since this planet always has sunlight you decide to have the organism derive all of its ATP from photosynthesis. Will you need to put the enzymes of the Kreb’s cycle in this organism? Briefly explain why or why not.

6)Fluoroacetate (F-CH2COO-) is a toxic agent produced by the plant Dichapetalum cymosum. In vitro studies of incubated rat hearts with fluoroacetate resulted in decreased rates of glucose uptake and glycolysis, and glucose 6-phosphate and fructose 6-phosphate had accumulated. The citric acid cycle intermediates were all at concentrations below normal, except for citrate with a concentration 10 times higher than normal.

a)What are the substrates, products, and enzymes for the citric acid cycle step blocked by fluoroacetate?

b)In the described experiment, why did glucose uptake and glycolysis slow down? Why did glucose 6-phosphate and fructose 6-phosphate accumulate?

c)Why is fluoroacetate poisoning fatal?