Notes from NEET topper
Two phases are involved in the CAM pathway:
Night time: The stomata opens during the night time (for capturing Co2) when the humidity is high and the temperature is cooler. The Co2 combines with phosphoenol pyruvate (PEP) in the presence of the enzyme PEPcarboxylase and forms a four-carbon compound, Oxaloacetic acid (OAA). Oxaloacetic acid is further converted into malic acid and stored in vacuoles of the chloroplast during the night time.
Day time. The stomata remain close and there is no gaseous exchange. The malic acid is transported from the vacuoles to the stroma where it is decarboxylated and Co2 is released.
Finally, this Co2 enters the Calvin cycle thereby completing the carbon fixation. The concentration of the Co2 around the enzyme RuBisCo ensures efficient carbon fixation.
Factors affecting photosynthesis
Both Internal and external factors influence the rate of photosynthesis. A lot of factors affect the photosynthesis process but the rate of the process is usually determined by the only one major factor that is present at a sub-optimal level.
