Question

the process of cellular respiration begins with molecules of ____ and ends with the production of ____.
a. energy; sugar
b. sugar; energy
c. oxygen; sugar
d. sugar; oxygen

Explanation:

Cellular respiration is the process by which cells break down glucose (sugar) to produce energy (ATP), carbon dioxide, and water. The process starts with sugar (glucose) as the initial substrate and ends with the production of energy (along with other by - products). Let's analyze each option:

• Option A: Energy is the end product, not the starting molecule, and sugar is the starting molecule, not the end product in this context. So A is incorrect.
• Option B: Cellular respiration begins with sugar (glucose) and through a series of metabolic reactions, energy (ATP) is produced. This matches the process of cellular respiration.
• Option C: Oxygen is used in the later stages (aerobic respiration) but is not the starting molecule, and sugar is the starting molecule, not the end product. So C is incorrect.
• Option D: Sugar is the starting molecule, and oxygen is used in aerobic respiration but is not the end product (the end product related to energy production is ATP, and waste products are carbon dioxide and water). So D is incorrect.

Answer:

B. sugar; energy