GPT on Question 12, Sep 22

Photosynthesis is the process plants, algae, and some bacteria use to turn light energy into chemical energy stored in sugar.

The basic equation

\[
6CO_2 + 6H_2O + \text{light energy} \rightarrow C_6H_{12}O_6 + 6O_2
\]

In words:

carbon dioxide + water + light → glucose + oxygen

Where it happens

In plants, photosynthesis occurs mainly in leaf cells inside structures called chloroplasts. Chloroplasts contain chlorophyll, the green pigment that absorbs light—especially red and blue wavelengths.

The two main stages

• 1.Light-dependent reactions
• •Occur in the thylakoid membranes of chloroplasts.
• •Chlorophyll captures sunlight.
• •Water molecules are split, releasing oxygen.
• •Light energy is converted into temporary chemical energy in molecules called ATP and NADPH.

• 2.The Calvin cycle
• •Occurs in the stroma, the fluid inside chloroplasts.
• •Uses carbon dioxide, ATP, and NADPH.
• •Produces small carbon-based molecules that the plant can use to make glucose and other organic compounds.

Why photosynthesis matters

• •It provides plants with stored chemical energy for growth and metabolism.
• •It produces much of the oxygen in Earth’s atmosphere.
• •It removes carbon dioxide from the air.
• •It forms the foundation of most food chains because animals obtain energy by eating plants or organisms that ate plants.

In short, photosynthesis converts sunlight into stored food energy while releasing oxygen as a by-product.