Kaplan Nursing Entrance Practice Exam

What process do plants use to convert sunlight into energy?

1. Photosynthesis

2. Respiration

3. Transpiration

4. Fermentation

The correct answer is: Photosynthesis

Plants utilize photosynthesis to convert sunlight into energy, which is fundamental to their growth and survival. During this process, chlorophyll, the green pigment in plant leaves, captures light energy from the sun. This captured light energy is then used to convert carbon dioxide and water into glucose, a type of sugar that serves as an energy source for the plant. Oxygen is released as a byproduct of this process, which is vital for the respiration of many living organisms. Photosynthesis is essential not only for plant life but also for life on Earth as a whole, as it forms the base of the food chain. The process takes place primarily in the leaves during daylight hours when sunlight is available. In contrast, respiration is the process by which plants and animals convert glucose and oxygen into energy, carbon dioxide, and water, essentially the reverse of photosynthesis. Transpiration refers to the movement of water through a plant and its evaporation from aerial parts, especially leaves, and fermentation is a metabolic process that converts sugar to acids, gases, or alcohol in the absence of oxygen. None of these processes involve the conversion of sunlight into usable energy like photosynthesis does.