Difference between c2 and c4 cycle
Answers
Answer:
The C2 photosynthetic pathway is more commonly known as photorespiration. This occurs most commonly when plants are in extremely hot and dry environments, forcing them to keep the pores on their leaves, known as stomata, closed to reduce water loss by transpiration. This allows O2 to build up in the air spaces between mesophyll cells (the cells most responsible for photosynthesis), because O2 is a waste product of photosynthesis that is normally released to the outside atmosphere. When O2 builds up in those air spaces, the enzyme rubisco will assimilate oxygen at the start of the Calvin cycle, rather than carbon dioxide. This produces a toxic 5-carbon compound that must be reduced using ATP; thus, the process of photorespiration is a net loss in ATP.
Explanation:
Answer:
The C2 photosynthetic pathway is more commonly known as photorespiration. This occurs most commonly when plants are in extremely hot and dry environments, forcing them to keep the pores on their leaves, known as stomata, closed to reduce water loss by transpiration. This allows O2 to build up in the air spaces between mesophyll cells (the cells most responsible for photosynthesis), because O2 is a waste product of photosynthesis that is normally released to the outside atmosphere. When O2 builds up in those air spaces, the enzyme rubisco will assimilate oxygen at the start of the Calvin cycle, rather than carbon dioxide. This produces a toxic 5-carbon compound that must be reduced using ATP; thus, the process of photorespiration is a net loss in ATP.
The C3 photosynthetic pathway is the most commonly used photosynthetic pathway. Plants in temperate climates without too much variability are usually C3 plants. In the Calvin cycle, a CO2 molecule is added as normal to the ribulose bisphosphate, producing an unstable 6-carbon intermediate that ultimately becomes a precursor to glucose molecules.
The C4 photosynthetic pathway is usually only seen in plants adapted to hot desert environments. This method of photosynthesis separates the light and dark reactions of photosynthesis in space. The light reactions will occur as normal in mesophyll cells; however, the Calvin cycle occurs one layer of cells deeper, within the bundle sheath cells of the plant. Carbon dioxide is fixed to a phosphoenolpyruvate molecule, producing malate; this malate is then pumped into the bundle sheath cell, where the carbon dioxide is released to the normal Calvin cycle.