?

AP® Biology

Free Version

Upgrade subject to access all content

Moderate

Free Energy and Cell Respiration

APBIO-MJRBQ9

The incremental oxidation of one molecule of glucose during cell respiration produces 30 molecules of ATP according the balanced equation:

$$C_{6}H_{12}O_{6} + 6O_{2} + 30ADP + 30P_{i} \rightarrow 6{H}_{2}O + 6C{O}_{2} + 30ATP$$

ATP is then hydrolyzed by cells for a variety of biochemical processes.

Changes in free energy between glucose oxidation and ATP hydrolysis were compared. The table below illustrates the data collected:

Reaction Change in Free Energy ($\Delta G$)
Glucose Oxidation -686 kcal/mol
ATP Hydrolysis -13 kcal/mol

$\ $

Which of the following statements BEST explains the data?

A

Both glucose oxidation and ATP hydrolysis are exergonic because they have negative $\Delta G$ values.

B

Both glucose oxidation and ATP hydrolysis are exergonic because their products have more free energy than their reactants.​

C

Both glucose oxidation and ATP hydrolysis are endergonic because they have negative $\Delta G$ values.

D

Both glucose oxidation and ATP hydrolysis are endergonic because their products have less free energy than their reactants.