Which term refers to the process of plants converting sunlight into energy?

Photosynthesis is the process by which plants, along with certain bacteria and algae, convert sunlight into chemical energy in the form of glucose. This remarkable process occurs mainly in the chloroplasts of plant cells, where chlorophyll absorbs sunlight. During photosynthesis, carbon dioxide from the atmosphere and water from the soil are combined using the energy from sunlight, resulting in glucose and oxygen as byproducts. This reaction is fundamental to life on Earth, as it provides the energy source for most organisms and contributes to the oxygen content of the atmosphere.

The other processes mentioned do not involve the direct conversion of light energy into chemical energy. Respiration, for instance, is the metabolic process where food molecules are broken down with the help of oxygen to release energy. Fermentation refers to an anaerobic process (occurring without oxygen) used by some organisms to obtain energy from glucose when oxygen is scarce. Transpiration is the process of water movement through a plant and its evaporation from aerial parts, especially the leaves, and it serves to help with nutrient uptake and cooling rather than energy conversion. Thus, photosynthesis is uniquely characterized by its role in harnessing sunlight and is central to the energy flow in ecosystems.