Question

While eukaryotic cells can use both glucose (C6H12O6) and hexanoic acid (C6H14O2) as fuel sources for cellular respiration, hexanoic acid yields more energy per gram when completely oxidized to CO2 and H2O. Select the reasons why hexanoic acid releases more energy upon complete combustion to CO2 and H2O.

a. Since hexanoic acid is more oxidized than glucose, complete oxidation of hexanoic acid generates more reducing equivalents that can enter the respiratory chain.
b. Hexanoic acid is more hydrogen rich than glucose, thus hexanoic acid is more reduced than glucose.
c. Glucose is more reduced than hexanoic acid, thus complete combustion of glucose requires more energy than the complete combustion of hexanoic acid.
d. Complete oxidation of hexanoic acid generates more reducing equivalents that can enter the respiratory chain than the complete oxidation of glucose.
e. Hexanoic acid is directly broken down into two molecules of acetyl-CoA. However, glucose is first broken down into two molecules of pyruvate, and then converted to acetyl-CoA, thus requiring more energy than the degradation of hexanoic acid.

Answer 1

b. Hexanoic acid is more hydrogen rich than glucose, thus hexanoic acid is more reduced than glucose.

d. Complete oxidation of hexanoic acid generates more reducing equivalents that can enter the respiratory chain than the complete oxidation of glucose.

Step-by-step explanation:

Hello,

In this case, the two options are b and d based on:

b. In organic chemistry, the presence of hydrogen and the absence of oxygen leads to a more reduced state, in such a way, when oxidizing a more reduced substance the released energy will be higher that when more oxidized since a longer path is performed.

d. Since the hexanoic acid is more reduced than the glucose, its oxidation involved a higher amount of reducing equivalents, serving as an electrons transferring which provides a higher amount of energy.

Best regards.

Answer 2

B. Hexanoic acid is more hydrogen rich than glucose, thus hexanoic acid is more reduced than glucose.

D. Complete oxidation of hexanoic acid generates more reducing equivalents that can enter the respiratory chain than the complete oxidation of glucose.

Step-by-step explanation:

From the structural formulas, we see that the carbon-bound H/C ratio of hexanoic acid (11/6) is higher than that of glucose (7/6). So, Hexanoic acid is more reduced and yields more energy on complete combustion to CO2 and H2O.