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Chemistry 160 Bioenergetics Homework key
1. Give the equation that relates free energy to the equilibrium constant.
ΔG = -RTlnK
2. What does it mean that ΔG are additive. Why is this important in metabolism?
It means that if there are several reactions in a process (such as metabolism) that the ΔG
for the process is the sum of the ΔG of the reactions. This is important because we can
still have a positive ΔG in a process while the overall ΔG is negative.
3. What molecule is the carrier for energy?
ATP
4. Give two reasons that hydrolysis of ATP releases energy.
increase ΔS, separation of negative charges, resonance stabilization of phosphate
5. How much energy is released per mole of ATP hydrolyzed?
7.3kcal = 30.5kJ
6. What is energy used for?
any number of things...motion, anabolism, fighting infections...what a stupid question!
7. Explain why hydrolysis of a thioester releases more energy than hydrolysis of an ester.
a thioester has no resonance between the sulfur and the oxygen while an ester does.
Therefore an ester has lower energy. when either is hydrolyzed, the result is a resonance
stabilized carboxylate ion.
8. What molecules are electron carriers?
NAD, FADH
9. For the electron carriers, which is used to oxidize Oxygen-containing groups and which
for carbon groups:
Oxygen: NAD
Carbon: FAD
10. Why is it advantageous to store energy in a diffusable molecule, like ATP and
electrons in diffusable molecules like NAD, FAD?
Because otherwise the energy or electrons would have to be used locally where
they are generated. Using diffusable molecules allows electrons or energy to be carried to
other locations to be used.
11. It is said that B vitamins are essential for energy. What are the roles of niacin,
riboflavin and pantothenic acid? (All of which are B vitamins) in bioenergetics?
Niacin is part of NAD, riboflavin is part of FAD and pantothenic acid is part of
coenzyme A
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