Botany - Photosynthesis in Higher Plants Question with Solution | TestHub

Dark reaction is also known as lightindependent phase. Unlike, light reaction, it does not require light as an essential factor. Thus can takes place both in the presence or absence of light. The term dark reaction does not mean that it takes place only in dark period or at night. ${\mathrm{CO}}_2$ fixation occurs in both ${\mathrm{C}}_3$ and ${\mathrm{C}}_4$ cycle. In ${\mathrm{C}}_3$ cycle, ${\mathrm{CO}}_2$ is added by the enzyme, RuBisco to a 5 carbon compound RuBP that is converted to 2 molecules of 3-carbon PGA. In ${\mathrm{C}}_4$ cycle the first product of ${\mathrm{CO}}_2$ fixation (takes place in mesophyll) is a 4-carbon compound, oxaloacetic acid. It is seen in some tropical plants.