Question

The dark reactions of photosynthesis require ATP and NADPH, are light-independent, and generate sugars. Which of the following options correctly describes the dark reactions of photosynthesis?

1) They require ATP and NADPH
2) They are light-independent
3) They generate sugars
4) All of the above

Answer 1

The dark reactions of photosynthesis, also known as the Calvin cycle, are light-independent and utilize ATP and NADPH produced in the light-dependent reactions to fix CO₂ into organic sugars. Option number 4 is correct.

Step-by-step explanation:

The Dark Reactions of Photosynthesis

The dark reactions of photosynthesis are a pivotal series of processes in plants whereby sugars are synthesized. These reactions, also known as the Calvin cycle or light-independent reactions, do not require light to proceed, hence the term 'dark'. Instead, they rely on the chemical energy stored in ATP and NADPH, which are produced during the earlier light-dependent reactions of photosynthesis. During the dark reactions, carbon dioxide (CO₂) is fixed from the atmosphere and, through a series of enzymatic steps, is converted into organic sugars that serve as an energy source for the plant.

To answer the student question directly: all the provided options correctly describe the dark reactions of photosynthesis. The options highlighted were:

1. 
   
3. They require ATP and NADPH
4. 
   
6. They are light-independent
7. 
   
9. They generate sugars

Therefore, the correct answer is (4) All of the above. These processes are critical for creating the glucose that provides energy and serves as a building block for various cellular functions within plants.