Question

question 10
the purpose of the cam or c4 pathways is to:
avoid photorespiration
produce nadph
confuse biology students
initiate atp formation
avoid photolysis

Explanation:

• CAM (Crassulacean Acid Metabolism) and C4 pathways: These are adaptations in plants to minimize photorespiration. Photorespiration is a wasteful process where the enzyme RuBisCO (which is central to the Calvin cycle in C3 plants) reacts with oxygen instead of carbon dioxide under certain conditions (like high temperature and low carbon dioxide availability).
• How they avoid photorespiration:
• In C4 plants, carbon dioxide is first fixed into a 4 - carbon compound in mesophyll cells. This 4 - carbon compound is then transported to bundle - sheath cells where carbon dioxide is released for the Calvin cycle. The concentration of carbon dioxide in bundle - sheath cells is high enough to favor the carboxylation (carbon - dioxide - fixing) reaction of RuBisCO over the oxygenation (photorespiration - causing) reaction.
• In CAM plants, stomata open at night (when the temperature is lower and water loss is less) to take in carbon dioxide. The carbon dioxide is fixed into organic acids and stored. During the day (when stomata are closed to reduce water loss), these organic acids release carbon dioxide for the Calvin cycle, maintaining a high enough carbon - dioxide concentration around RuBisCO to avoid photorespiration.
• Other options:
• NADPH is produced in the light - dependent reactions of photosynthesis (not the main purpose of CAM or C4 pathways).
• Confuse biology students is a joke option and not a valid biological purpose.
• ATP formation is a general part of cellular metabolism (including in the light - dependent reactions of photosynthesis) but not the specific purpose of CAM or C4.
• Photolysis (the splitting of water molecules in the light - dependent reactions) is not related to what CAM or C4 pathways are trying to avoid.

Answer:

avoid photorespiration