Question

a graph showing the energy of the reactants and products of cellular respiration is shown here. which description accurately compares the products and reactants of cellular respiration in terms of energy level? a glucose is a reactant and has less energy than carbon dioxide, a product. b oxygen gas and glucose are products and have a lower energy level than the reactants. c water and carbon dioxide are products and have a lower energy level than the reactants. d oxygen gas is a reactant and has the same energy as the water molecule that is produced. graph: gibbs free energy (y - axis), time (x - axis); reactants (a) have higher energy, products (b) lower, δg < 0, energy released.

Explanation:

1. Recall the cellular respiration equation: \( \text{C}_6\text{H}_{12}\text{O}_6 + 6\text{O}_2

ightarrow 6\text{CO}_2 + 6\text{H}_2\text{O}+\text{Energy} \). Reactants are glucose (\( \text{C}_6\text{H}_{12}\text{O}_6 \)) and oxygen (\( \text{O}_2 \)); products are \( \text{CO}_2 \), \( \text{H}_2\text{O} \), and energy.

1. The graph shows \( \Delta G < 0 \), meaning it's an exergonic reaction (energy released), so products have lower energy than reactants.
2. Analyze options:

• Option A: Glucose is a reactant, but carbon dioxide is a product. The comparison of energy between glucose and \( \text{CO}_2 \) is not the focus here (reactants vs products overall). Eliminate A.
• Option B: Oxygen and glucose are reactants, not products. Eliminate B.
• Option C: Reactants of cellular respiration are glucose and oxygen; products are water and carbon dioxide. The graph shows products (B) have lower energy than reactants (A) (since \( \Delta G < 0 \), energy is released, so products are lower energy). This matches.
• Option D: Oxygen is a reactant, water is a product. The claim that oxygen (reactant) has the same energy as water (product) is wrong because products have lower energy. Eliminate D.

Answer:

C. Water and carbon dioxide are products and have a lower energy level than the reactants.