Photosynthesis vs. Cellular Respiration

Difference Between Photosynthesis and Cellular Respiration


Photosynthesis and cellular respiration are used by organism to get energy. Photosynthesis is a process in which plants converts the sunlight into sugar and oxygen. On the other hand, cellular respiration is a process in which cells get energy from the food molecules. Both the processes are important for life.


Plants, algae and some bacteria are photoautotroph. Photosynthesis occurs in them. A set of chemical reactions is involved in the process. With the help of light, photoautotroph converts water and carbon dioxide into glucose. The oxygen is released to the atmosphere in the process. Photosynthesis occurs when proteins absorb light energy. The proteins contain chlorophylls. Chloroplasts are contained in the plasma membrane of the plants cells.

Photosynthesis can takes place in two ways- Light dependent photosynthesis and light independent reaction photosynthesis. The sunlight is necessary in the light dependent photosynthesis. When light reacts with water and photons, oxygen is released which leads to the production of NADPH and ATP. In light independent photosynthesis, carbon dioxide is used to form phophogylcerides which forms sugar and starch. These starch and sugar are stored in the plant for future use. It is in the form of fruits.

Oxygen is the byproduct of photosynthesis. Thus photosynthesis is crucial for life on earth.

Cellular Respiration

Cellular respiration is the method in which cells obtain energy from organic compounds or food. In this process cells drive energy from glucose in the form of ATP. Carbohydrates, fats and proteins are used as fuels in the process of cellular respiration. There are two types of in all living organisms. These are aerobic respiration and anaerobic respiration. Aerobic respiration takes place in the presence of oxygen while anaerobic respiration takes place without oxygen. Eukaryotic cells carry out the reparation in the mitochondria while prokaryotic cells carry out the process in the cytoplasm. Let us discuss both the types of respiration in some detail.

In aerobic respiration, glucose is used as the source of energy in the presence of oxygen. More energy is formed in the form of ATP. In this process glucose passes through glycolysis and it goes through PTCA. Following is formula of Aerobic respiration.

                C6 H12 O6 (aq)+6O2(g) – 6Co2 (g)+6H2O(l) + Energy.

Most of anaerobic bacteria sue anaerobic respiration when there is low supply of oxygen. The process of fermentation is involved in it. Glycolysis and Kerb cycle is the first step in this type of respiration. Two ATP molecules are yielded in this process. Those ATP molecules are used in fermentation.


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