Photosynthesis is a process used by plants and some algae to convert light energy, or energy from the sun, into chemical energy and storing it in the bonds of sugar. This will later be released to fuel the organisms’ activities. Photosynthesis is the most important biological process on Earth. It completes the carbon cycle by absorbing atmospheric CO2 and releasing free oxygen. In other words, it gives us oxygen to breathe.
Cellular respiration is the process by which the chemical energy of “food” molecules or waste products are released, and partially captured in the form of ATP, carbohydrates, fats, and proteins. It can be divided into three metabolic processes which are glycolysis, the Krebs cycle, and oxidative phosphorylation.
Both are used in plants and other organisms, they work together to make oxygen, and survive. What their difference basically is that photosynthesis makes glucose molecules, while cellular respiration breaks them down. Photosynthesis involves the production of carbohydrates by plants, while cellular respiration is the use of carbohydrates by cells of plants and animals. Photosynthesis captures light energy and converts it to chemical energy, while cellular respiration takes that chemical energy and breaks it down, releasing energy. The energy in photosynthesis is solar energy converted to chemical energy. The energy in cellular respiration is the stored chemical energy that originated from photosynthesis, and this chemical energy is converted to other kinds of energy like heat and motion.
In conclusion, plants use carbon dioxide and water to make sugar and release oxygen as a byproduct, while animals use sugar and oxygen to create energy, and release carbon dioxide as waste.