Both photosynthesis and cellular respiration are the main pathways of energy transportation in organisms. However, the reactants and the products are exact opposites in photosynthesis and in cellular respiration. In photosynthesis, cells take in carbon dioxide (CO2) and water (H2O) by absorbing energy from the sun, and then the cells release oxygen (O2) and store glucose (C6H12O6). The formula of photosynthesis is: Light energy
6CO2+6H2O → C6H12O6+6O2 In cellular respiration, glucose and oxygen are taken into the cells, then they are converted to carbon dioxide, water and ATP energy and some other energy. Some of the ATP energy is used in photosynthesis; a large amount of energy is used up as heat, only a little energy is stored in the cells. The formula of cellular respiration is: C6H12O6+6O2 → 6CO2+6H2O+ATP
Both processes take place inside the cells. In contrast, The site of photosynthesis is chloroplast, while the sites of cellular respiration are cytoplasm and mitochondrion. The chloroplast, which has two membranes around a central aqueous space, is found mainly in mesophyll cells forming the tissues in the interior of the leaf. The chloroplast is made of grana, thylakoid, and stroma. Chlorophyll, which is a green pigment, is located in the chloroplasts. The mitochondrion also has two membranes, the outer membrane and the inner membrane. Inside the inner membrane is the matrix, folded by cristae. Both chloroplast and mitochondrion also contain DNA and RNA, and they are found only in eukaryotic cells. Photosynthesis is a redox reaction, which reverses the direction of electrons flow in respiration. Through photosynthesis, water is split and electrons are transported with H﹢from the water, into carbon dioxide, then reducing it to sugar. There are two main stages of photosynthesis, which are the light reactions (photo) and the Calvin cycle (synthesis). In the light reactions, light energy,...
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