Give three advantages of the C 4 cycle over the C 3 cycle.

Advantages of the C4 cycle over the C3 cycle: (i) In a hot and dry environment, C4 photosynthesis is more efficient than C3 photosynthesis. (ii) C4 plants do not perform photorespiration in low concentrations of CO 2 . (iii) C4 plants keep their stomata close for a long duration to prevent transpiration.

Give three advantages of the C 4 cycle over the C 3 cycle.

Advantages of the C4 cycle over the C3 cycle: (i) In a hot and dry environment, C4 photosynthesis is more efficient than C3 photosynthesis. (ii) C4 plants do not perform photorespiration in low concentrations of CO 2 . (iii) C4 plants keep their stomata close for a long duration to prevent transpiration.

Name any two C 4 plants. Give anatomical characters of these plants.

In the C4 plants, initial carbon fixation takes place in mesophyll cells and the Calvin cycle takes place in bundle-sheath cells. PEP carboxylase catalyzes the reaction during which carbon dioxide molecule combines with the three-carbon molecule phosphoenolpyruvate (PEP), producing oxaloacetate (a four-carbon molecule). Examples of C4 plants: sugarcane and crabgrass. The anatomical characters : (1) Their mesophyll cells are undifferentiated and the cells occur in concentric layers around the vascular bundles. (ii)The chloroplasts of mesophyll cells are very small in C4 plants.