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Problem 43
Why is ATP sometimes called a high-energy molecule?
Problem 44
What general kind of chemical reaction does ATP participate in?
Problem 45
What does it mean when we say that two reactions are coupled?
Problem 47
Write the reaction for the hydrolysis of 1,3-bisphosphoglycerate coupled to the phosphorylation of ADP using the curved-arrow symbolism.
Problem 49a
FAD is a coenzyme for dehydrogenation.
a. When a molecule is dehydrogenated, is FAD oxidized or reduced?
Problem 49b
FAD is a coenzyme for dehydrogenation.
b. Is FAD an oxidizing agent or a reducing agent?
Problem 49d
FAD is a coenzyme for dehydrogenation.
d. What is the form of FAD after dehydrogenation?
Problem 51
What is the purpose of the citric acid cycle?
Problem 52
Where in the cell does the citric acid cycle take place?
Problem 54
What is the final fate of the carbons in acetyl-CoA after several turns of the citric acid cycle?
Problem 55a
Look at the eight steps of the citric acid cycle (Figure 21.8) and answer the following questions:
a. Which steps involve oxidation reactions?
Problem 55b
Look at the eight steps of the citric acid cycle (Figure 21.8) and answer the following questions:
b. Which steps involve decarboxylation (loss of CO2)?
Problem 55c
Look at the eight steps of the citric acid cycle (Figure 21.8) and answer the following questions:
c. Which step or steps involve a hydration reaction?
Problem 56
How many NADH and how many FADH2 molecules are formed in the citric acid cycle?
Problem 57
Which reactions of the citric acid cycle transfer energy as FADH2?
Problem 58
Which reactions of the citric acid cycle transfer energy as NADH?
Problem 59
What are the two primary functions of the electron-transport chain?
Problem 61
What two coenzymes are involved with initial events of the electron-transport chain?
Problem 62
What are the ultimate products of the electron-transport chain?
Problem 64b
What do the following abbreviations stand for?
b. CoQ
Problem 64c
What do the following abbreviations stand for?
c. NADH/H+
Problem 65
What atom in the cytochromes undergoes oxidation and reduction in the electron-transport chain? What atoms in coenzyme Q undergo oxidation and reduction in the electron-transport chain?
Problem 68
What would happen to the citric acid cycle if NADH and FADH2 were not reoxidized?
Problem 69
What does the term “oxidative phosphorylation” mean? What is substrate-level phosphorylation? Are these processes the same? Explain.
Problem 70
In oxidative phosphorylation, what is oxidized and what is phosphorylated?
Problem 71a
Oxidative phosphorylation has three reaction products.
a. What is the energy-carrying product?
Problem 72
What supplies the energy to drive oxidative phosphorylation?
Problem 76
Why must the breakdown of molecules for energy in the body occur in several steps, rather than in one step?
Problem 79
With what class of enzymes are the coenzymes NAD+ and FAD associated?
Problem 80
We talk of burning food in a combustion process, producing CO2 and H2O from food and O2. Explain how O2 is involved in the process although no O2 is directly involved in the citric acid cycle.