Final answer:
Cellular respiration is the process by which the body converts the energy in food into ATP, the energy used by cells. Glucose, produced by plants through photosynthesis, is broken down to release this energy.
Step-by-step explanation:
Through the process of cellular respiration, the energy in food is changed into energy that can be used by the body's cells. During this process, glucose derived from food undergoes a series of reactions in the presence of oxygen, resulting in the production of carbon dioxide and water, and importantly, the transfer of energy to adenosine triphosphate (ATP), the energy-carrying molecule that fuels cellular activities.
The initial step involves the digestion of food into simple sugars like glucose, which is a monosaccharide. Glucose or polysaccharides such as starch, which are comprised of many glucose units, then provide the energy required by organisms. Photosynthesis is crucial for this process as it is responsible for converting solar energy into chemical energy stored in glucose bonds, which plants produce, and which eventually become the energy source for other organisms upon consumption.