Which statement correctly describes the relationship between photosynthesis and respiration at a cellular level in energy transformation?

Which statement correctly describes the relationship between photosynthesis and respiration at a cellular level in energy transformation?

• A. Photosynthesis stores chemical energy by converting CO2 and water into glucose and O2; respiration releases CO2 and water to release energy.
• B. Respiration releases CO2; photosynthesis consumes CO2.
• C. Both require light energy input in the same cell.
• D. Only respiration occurs in plants.

Answer: (D)

Cells transform energy in two linked ways. During photosynthesis, light energy is captured to drive the synthesis of glucose from carbon dioxide and water, storing energy in the chemical bonds of glucose and releasing oxygen as a byproduct. In cellular respiration, glucose is broken down with oxygen to produce ATP, releasing energy stored in the glucose as CO2 and water. These processes form a cycle: the products of photosynthesis feed respiration, while the outputs of respiration (CO2 and water) are used again in photosynthesis. In plants, both processes occur—photosynthesis in chloroplasts (mostly daylight) and respiration in mitochondria (day and night). The idea that only respiration occurs in plants is incorrect.

Cells transform energy in two linked ways. During photosynthesis, light energy is captured to drive the synthesis of glucose from carbon dioxide and water, storing energy in the chemical bonds of glucose and releasing oxygen as a byproduct. In cellular respiration, glucose is broken down with oxygen to produce ATP, releasing energy stored in the glucose as CO2 and water. These processes form a cycle: the products of photosynthesis feed respiration, while the outputs of respiration (CO2 and water) are used again in photosynthesis. In plants, both processes occur—photosynthesis in chloroplasts (mostly daylight) and respiration in mitochondria (day and night). The idea that only respiration occurs in plants is incorrect.