Part I: Short answer. Please use complete sentences. You may use structures and equations when necessary.

4. (20 points) What enzymes from the Kreb=s cycle are regulated by allosteric interactions, covalent modification or both? Draw the structures of all of the reactants and products for all of the reactions that are regulated. Fully discuss how each enzyme is regulated. Give an example of a disease that results from a defect in one of these enzymes.

5. (10 points) Explain (in detail) why fatty acids with an even number of carbons can not be used to synthesize glucose. Also explain why fatty acids with an odd number of carbons can be used to make glucose. Be sure to include relevant biochemical reactions to support your answer.

6. (10 points) Combine the Alanine-Glucose cycle and the Cori cycle in one picture. You can use names of compounds or draw the structures. For the key steps, please provide the name of the enzyme involved. Explain how these cycles exacerbate the hyperglycemic state in a diabetic patient.

7. (10 points) A new wonder diet pill is being advertized, AEat everything and stay svelte!@ Unfortunately it has a nasty side effect of over heating the consumer and could result in death. You suspect that the wonder pill is an uncoupler. Describe how an uncoupler works, and propose an experiment to determine if this compound is an uncoupler.

8. Elephant seals are sea mammals that obtain all of their water via metabolism. Their diets consist mainly of squid, and these delicious morsels have a very high fat content. In addition to using stored fat for insulation, they also use fat stores as a source of water.

a. (10points) What are the specific reactions that produce water.

b. (10 points) How many moles of water are generated per mole of palmitate? (Your reasoning is the important part of this answer. Please demonstrate how you determined this number.)

c. (10 points) How many liters of water can be obtained from β-oxidation of 5 lbs of palmitic acid? (The density of water is 1 g/mL.)

9. (10 points) The energy for the synthesis of ATP in the mitochondria comes from the pH gradient that exists across the inner mitochondrial membrane. If the pH of the mitochondrial matrix is 7.2 and the pH of the inner membrane space is 6.8, what is the ΔG for the flow of protons into the matrix? The membrane potential is -0.28V (inside is negative). The temperature is 25EC.

10. (10 points) If each mole of ATP requires 51.8kJ of energy, how many moles of ATP can be made from the transport of 5 moles of protons? (Use the value for ΔG that you obtained in the preceding question.)

11. (20 points) Compare the net yield of ATP from the complete oxidation of hexanoic acid versus the complete oxidation of glucose. Then, based on the caloric content of fats and sugars, calculate the number of ATP that could be made from a mole of glucose and from a mole of hexanoic acid (hexanoic acid= 9kcal/gram) and (sugar glucose=4 Kcal/gram) Each ATP requires 51.8 kJ to synthesize. Now, compare the values that you obtained in from biological oxidation versus your caloric content calcuations. Are they the same? Account for any differences.

14. Fully describe the regulation mechanisms for glycolysis. What glycolytic enzymes are allosterically regulated? What glycolytic enzymes are covalently modified? How are they inhibited? How are they stimulated?