Question

1) C₄ photosynthesis resists photorespiration by

            a. separating the light reactions and the carbon reactions into separate cells.

            b. combining the light reactions and the carbon reactions into the same cells.

            c. cooperate with C3 photosynthetic plants and perform only the light reactions.

            d. having the light reactions occur in the mitochondria instead of the chloroplasts.

Answer 1

C₄ photosynthesis resists photorespiration by separating the light reactions and the carbon reactions into separate cells

C4 plant have special leaf anatomy which allow to plant fix carbon in two stages with 1 additional cycle. in C4 plant carbon in fix in 4 carbon compound in mesophyll cells with help of PEP carboxylase enzyme (this enzyme have only carboxylase activity and have high affinity to only with CO2) this fixed 4C compound transfer in bundle sheath cell where actual calvin cycle fix CO2 into glucose/sugar with help of Rubisco enzyme. due to sufficient availability of CO2 in bundle sheath cell Rubisco does not affected by oxygen and there is no photorespiration.