Question

What role does light play in photosynthesis?

• A. Catalyze synthesis of ATP
• B. Provides heat energy for leaves to convert into light energy
• C. Excites electron from carotene which is taken up for photophosphorylation
• D. Both B and C

Answer 1

The correct option is D

Both B and C

The correct option is option D.

The explanation for correct options:

Option B:

1. In photosynthesis, light energy is converted to chemical energy in the form of sugars.
2. Chlorophyll ( a pigment involved in photosynthesis ) absorbs light energy, which is then utilized to change carbon dioxide from the air and water from the soil into glucose, a type of sugar.

Option C:

1. Photophosphorylation involves the synthesis of ATP from ADP and inorganic phosphate in the presence of light, where the phosphate group is transferred into ADP and produces ATP.
2. By transferring light energy to the carotene, electrons are encouraged to enter a higher quantum energy state.
3. The pigment can transfer the excited electrons for photophosphorylation to other carriers with higher reduction potentials since it has a considerably lower reduction potential in its energized form.

The explanation for the incorrect option:

Option A:

In photosynthesis, ATP is synthesized by the protein ATP synthase, where electrons are transferred from the intermembrane space.

Final answer: Light play role in photosynthesis by providing heat energy for leaves to convert into light energy and excites an electron from carotene, which is taken up for photophosphorylation.