09/01/2018 · Process of Photosynthesis ..
Cellular respiration is the process of breaking down food molecules to obtain energy and store it in the form of adenosine triphosphate (ATP) molecules.
Plant cells, after creating sugar molecules through photosynthesis, undergo cellular respiration to create ATP molecules.
Photosynthesis in plants occurs in two stages
Photosynthesis is a process where by energy from light is harvested and used to drive synthesis of organic carbohydrates from carbon dioxide and water. Photosynthesis takes place in chloroplasts and can be divided into two steps: light reactions which require light and dark reactions which do not require light. During light reaction, light energy is captured by photosystems and electrons are transferred among the electron receptors. ATP and NADPH are generated. During dark reactions, CO2 is fixed using ATP and NADPH generated by the light reactions and organic carbohydrates are synthesized via the Calvin Cycle. When the CO2 is first fixed into a 3 carbon compound 3PGA, it is called C3 pathways and these plants are called C3 plants. The disadvantage of C3 plants is that they undergo photorespiration and thus waste some energy gained in light reactions. C4 cycle is the pathway adopted by C4 plants to bypass photorespiration.
Participants in Photosynthesis
Chloroplasts are organelles specialized for photosynthesis. Inside chloroplasts are chlorophyll, proteins which can absorb light. Photosystems are many proteins together which can gather and amplify light energy. NADPH is an energy carrier in plants and ATP synthase produces the ATP.