What is the primary purpose of cellular respiration?

• A. To convert light energy into chemical energy
• B. To convert biochemical energy from nutrients into ATP
• C. To produce oxygen for photosynthesis
• D. To synthesize proteins

Answer: (B)

The primary purpose of cellular respiration is to convert biochemical energy from nutrients, specifically glucose, into adenosine triphosphate (ATP), which serves as the main energy currency of the cell. This process occurs in multiple stages, including glycolysis, the Krebs cycle, and the electron transport chain. Cellular respiration is fundamental for providing cells with the energy required to perform various functions such as growth, repair, and maintenance of cellular activities.

In contrast, converting light energy into chemical energy is a function of photosynthesis rather than cellular respiration. Producing oxygen for photosynthesis is also not a purpose of cellular respiration; instead, cellular respiration consumes oxygen and produces carbon dioxide as a byproduct. The synthesis of proteins is a separate cellular process that relies on the energy provided by ATP but is not a direct outcome of cellular respiration itself. Thus, the focus of cellular respiration on converting nutrients into ATP distinctly identifies option B as the correct answer.