AP BIOLOGY

Detailed explanation-1: -C3 plants have the disadvantage that in hot dry conditions their photosynthetic efficiency suffers because of a process called photorespiration. When the CO2 concentration in the chloroplasts drops below about 50 ppm, the catalyst rubisco that helps to fix carbon begins to fix oxygen instead.

Detailed explanation-2: -As a plant’s environment becomes hot, dry, and bright, its stomata, where carbon dioxide enters the leaf, tend to close. This lowers the concentration of carbon dioxide into the Calvin cycle, causing the cycle to accept oxygen in place of the carbon dioxide and makes a new product.

Detailed explanation-3: -The lower photosynthetic efficiency in C3 plants is due to a dual activity in the enzyme that fixes CO2, Ribulose-1, 5-bisphosphate carboxylase/oxygenase (RuBisCO; Brown et al., 2011).

Detailed explanation-4: -The high temperature will make the plant close its stomata to reduce water loss by evaporation. If the stomata is closed, the oxygen from photosynthesis will build up inside the leaf while the carbon dioxide will not get into the leaf.