Many proteins are enzymes (they catalyze reactions). Thus, it is necessary to re

Question

Many proteins are enzymes (they catalyze reactions). Thus, it is necessary to review how reactions take place. Reduced organic compounds tend to contain stored energy in C–H bonds. As a general rule, the greater the number of C–H bonds, the greater the amount of potential energy stored in the molecule. Answer each question in the chart as it relates to the two reactions shown at the top. Be sure to be prepared to explain the reasoning behind your answers.

Reaction 1:

CH4 + 2O2 2H2O + CO2

(methane)

Reaction 2:

6 CO2 + 6 H2O C6H12O6 + 6O2

a.
Is the reaction exergonic or endergonic?

b. Is the reaction spontaneous?

c. Is the reaction anabolic or catabolic?

d. Is G (the change in free energy) positive or negative?

Reaction 1:

CH4 + 2O2 2H2O + CO2

(methane)

Reaction 2:

6 CO2 + 6 H2O C6H12O6 + 6O2

a.
Is the reaction exergonic or endergonic?

b. Is the reaction spontaneous?

c. Is the reaction anabolic or catabolic?

d. Is G (the change in free energy) positive or negative?

Explanation / Answer

Answer a. Is the reaction exergonic or endergonic?
Exergonic would mean release in energy while endergonic would mean absorption of it. As such Reaction 1 (henceforth R1) shows lesser C-H bonds in product side and is hence exergonic while Reaction 2 (henceforth R2) shows more C-H bonds in product side and is hence endergonic. The given change in energy needs to occur for the reactants to turn into products.

Answer b. Is the reaction spontaneous?
Generally, Exergonic reactions are energy giving hence they become more stable, entropy increases which is why these reactions are spontaneous in nature. The opposite is true for endergonic reactions.
R1 = Yes, reaction is spontaneous
R2 =  No, reaction is not spontaneous

Answer c. Is the reaction anabolic or catabolic?
Generally, anabolic is when elements from to or more compounds combine together and the average atoms on a compound increases after a reaction. The opposite is true for catabolic.
R1 = Catabolic
R2 = Anabolic

Answer d. Is G (the change in free energy) positive or negative?
Generally, spontaneous reactions give out energy and hence the change in free energy required is negative. The opposite is true for non-spontaneous reactions and positive G.
R1 = G is negative
R2 = G is positive

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