Assertion and Reason Questions for Chapter 2 Class 9:

Assertion: The process of photosynthesis involves the conversion of light energy into chemical energy.
Reason: Chlorophyll present in the chloroplasts of plant cells absorbs light energy to drive the photosynthetic process.

Explanation:
- Photosynthesis Process: Photosynthesis is a process in which green plants, algae, and some bacteria use sunlight to synthesize foods with the help of chlorophyll.
- Conversion of Light Energy: During photosynthesis, light energy is absorbed by chlorophyll in the chloroplasts of plant cells. This light energy is then converted into chemical energy in the form of glucose.
- Role of Chlorophyll: Chlorophyll is a pigment that absorbs light energy required for photosynthesis. It is located in the thylakoid membranes of chloroplasts and is essential for capturing sunlight.
- Photosynthetic Process: In the presence of sunlight, chlorophyll molecules absorb light energy and transfer it to other molecules in the thylakoid membranes. This energy is used to split water molecules, release oxygen, and produce ATP and NADPH for the Calvin cycle.
- Chemical Energy Production: The chemical reactions in photosynthesis result in the production of glucose, which serves as the primary source of energy for plants and other organisms.

In conclusion, the assertion that the process of photosynthesis involves the conversion of light energy into chemical energy is true because chlorophyll plays a crucial role in absorbing light energy to drive the photosynthetic process and produce glucose as a form of chemical energy.