Question

question 20
(02.06 mc)
how would cellular respiration be impacted in the absence of photosynthesis?
○ only aerobic respiration would take place.
○ only anaerobic respiration would take place.
○ fewer atp would be produced during cellular respiration.
○ both reactants of cellular respiration would not be available.

Explanation:

1. Analyze the relationship between photosynthesis and cellular respiration: Photosynthesis produces glucose (a reactant for cellular respiration) and oxygen (a reactant for aerobic respiration). Cellular respiration reactants are glucose and oxygen (for aerobic) or just glucose (for anaerobic).
2. Evaluate each option:

• Option 1: Aerobic respiration needs oxygen, which photosynthesis helps produce. Without photosynthesis, oxygen would deplete, so aerobic respiration can't only occur. Eliminate.
• Option 2: Anaerobic respiration doesn't need oxygen, but it still needs glucose. Without photosynthesis, glucose production (from plants) would stop, so anaerobic can't be the only one. Eliminate.
• Option 3: The number of ATP depends on the type of respiration and available reactants, but the main issue is reactant availability, not just ATP quantity. Eliminate.
• Option 4: Cellular respiration reactants are glucose (produced by photosynthesis in plants, or from plant - based sources in other organisms) and oxygen (produced by photosynthesis). Without photosynthesis, over time, glucose (from plant matter) and oxygen (from photosynthetic organisms) would not be available. So both reactants of cellular respiration would not be available.

Answer:

D. Both reactants of cellular respiration would not be available.