Which step marks the beginning of photosynthesis in plants?

• A. Transport of sugars through the phloem
• B. Fixation of carbon dioxide into glucose
• C. Absorption of light energy by chlorophyll
• D. Release of oxygen from water

Answer: (C)

Verified step by step guidance

1. Understand the process of photosynthesis: Photosynthesis is the process by which plants convert light energy into chemical energy stored in glucose. It occurs in two main stages: the light-dependent reactions and the Calvin cycle (light-independent reactions).
2. Identify the role of chlorophyll: Chlorophyll is a pigment found in the chloroplasts of plant cells. It plays a crucial role in capturing light energy from the sun, which is necessary to drive the photosynthetic process.
3. Recognize the first step in photosynthesis: The process begins with the absorption of light energy by chlorophyll molecules in the thylakoid membranes of the chloroplast. This light energy excites electrons, initiating the light-dependent reactions.
4. Eliminate incorrect options: The transport of sugars through the phloem occurs after photosynthesis, and the fixation of carbon dioxide into glucose happens during the Calvin cycle, which is a later stage. The release of oxygen from water is a result of the light-dependent reactions but not the initiating step.
5. Conclude that the correct answer is the absorption of light energy by chlorophyll, as it marks the beginning of the photosynthetic process by capturing the energy needed to drive subsequent reactions.