Which of the following correctly identifies the two main stages of photosynthesis?

• A. Glycolysis and Krebs cycle
• B. Oxidative phosphorylation and photolysis
• C. Electron transport chain and fermentation
• D. Light-dependent reactions and Calvin cycle

Answer: (D)

Verified step by step guidance

1. Understand the process of photosynthesis: Photosynthesis is the process by which plants, algae, and some bacteria convert light energy into chemical energy stored in glucose. It occurs in two main stages: the light-dependent reactions and the Calvin cycle.
2. Learn about the light-dependent reactions: These reactions occur in the thylakoid membranes of chloroplasts. They require light energy to produce ATP and NADPH, which are energy carriers. Water is split during this stage, releasing oxygen as a byproduct.
3. Understand the Calvin cycle: This stage occurs in the stroma of chloroplasts and does not require light directly. It uses ATP and NADPH produced in the light-dependent reactions to convert carbon dioxide into glucose through a series of enzyme-mediated steps.
4. Compare the options provided: Glycolysis and Krebs cycle are part of cellular respiration, not photosynthesis. Oxidative phosphorylation and photolysis are processes related to energy production but do not describe the two main stages of photosynthesis. The electron transport chain and fermentation are also unrelated to photosynthesis.
5. Conclude that the correct answer is the light-dependent reactions and the Calvin cycle, as these are the two main stages of photosynthesis that work together to convert light energy into chemical energy.