The Relationship of Free-Energy Change (ΔG) to the Concentrations of Reactants

question 16

Multiple Choice

The relationship of free-energy change (ΔG) to the concentrations of reactants and products is important because it predicts the direction of spontaneous chemical reactions.Consider, for example, the hydrolysis of ATP to ADP and inorganic phosphate (P_i) .The standard free-energy change (ΔG°) for this reaction is −7.3 kcal/mole.The free-energy change depends on concentrations according to the following equation:
ΔG = ΔG° + 1.42 log₁₀ ([ADP] [P_i]/[ATP])
In a resting muscle, the concentrations of ATP, ADP, and P_i are approximately 0.005 M, 0.001 M, and 0.010 M, respectively.At [P_i] = 0.010 M, what will be the ratio of [ATP] to [ADP] at equilibrium?

• A)1.38 × 10⁶
• B)1
• C)7.2 × 10⁻⁸
• D)5.14

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Definitions:

Perennial Herbaceous Plants

Plants that live for more than two years, lacking woody stems, and dying back at the end of the growing season only to regrow from the same root system.

Scramble Competition

See Exploitation Competition.

Intraspecific

Pertaining to interactions or relationships occurring within the same species, such as competition or mating.

Negative Feedback

A regulatory mechanism in which a stimulus causes an opposite output in order to maintain an optimal level of whatever is being regulated.