Biology Unit 4: C1.3 Photosynthesis

What is photosynthesis?

The process by which plants, algae, and some bacteria convert light energy into chemical energy stored in glucose.

What is the word equation for photosynthesis?

Carbon dioxide + Water → Glucose + Oxygen
(with light energy)

What is the balanced chemical equation for photosynthesis?

6CO₂ + 6H₂O → C₆H₁₂O₆ + 6O₂
(with light and chlorophyll)

Where does photosynthesis occur?

In the chloroplasts of plant cells and algae.

What pigment is essential for photosynthesis?

Chlorophyll, which absorbs light energy.

What colors of light are most effective for photosynthesis?

Blue and red light.

Which color of light is least effective for photosynthesis?

Green, because it is mostly reflected, not absorbed.

What happens to the rate of photosynthesis as light intensity increases?

It increases until a plateau is reached (when another factor becomes limiting)

What are the three main limiting factors of photosynthesis?

• Light intensity

• Carbon dioxide concentration

• Temperature

How does temperature affect photosynthesis?

Increases rate until an optimum, then decreases due to enzyme denaturation.

How does carbon dioxide concentration affect photosynthesis?

Rate increases with more CO₂, until saturation is reached.

How is oxygen produced during photosynthesis?

From the photolysis of water during the light-dependent reactions.

What molecule is split during photolysis?

Water (H₂O) is split into H⁺, electrons, and O₂.