C₃ plants and C₄ plants show different carbon dioxide concentration saturations. At high intensities of light, C₄ plants show carbon dioxide saturation at 360 μlL^-1 while C₃ plants show saturation at 450 μlL^-1.

RuBP or Ribulose bisphosphate is a 5-carbon ketose sugar. It is primary acceptor of carbon dioxide in photosynsis. OAA is a 4-carbon organic acid while PGA is a 3-carbon organic acid.

During process of photorespiration, active site of RuBisCO binds to oxygen. ATP and sugars are not formed. Instead of PGA, 1 molecule of phosphoglycerate and phosphoglycolate are formed.

For every carbon dioxide molecule used up in Calvin cycle, 2 molecules of NADPH are required. Hence, 2 molecules of NADP are produced. For six Calvin cycles, 12 molecules of NADP are produced.

In C₃ plants, first stable product of carbon dioxide fixation is 3-PGA or 3-phosphoglyceric acid. For C₄ plants, it is OAA or oxaloacetic acid. C₄ plants lack photorespiration. The Calvin cycle is common to both.

The first electron acceptor in photosystem 1 is a Fe-S protein. It is a stable complex of iron and sulfur atoms bonded to a protein. It primarily accepts electrons and passes onto NADP⁺.

In plants showing Kranz anatomy, bundle sheaths surrounding vascular bundles have characteristics such as thick walls, a large number of chloroplasts and no intercellular spaces. They are layered around vascular bundles.

Carbon dioxide is entering photosyntic pathway through dark reaction. RuBP reacts with CO₂ to form first unstable carbon compound. So, here 6 molecules of CO₂ are required to start dark reaction.

The genetic predisposition or genetic make up of a plant is an internal factor that affects rate of photosynsis. The arrangement of genes present in plant is expressed in a certain way in different plants.

The most crucial step of Calvin cycle is carboxylation, where carbon dioxide is fixated into a stable organic intermediate, known as ribulose bisphosphate. RuBP carboxylase catalyses carboxylation.