GPT on Question 12, Sep 26

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

The overall 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 mainly occurs 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 chloroplast’s thylakoid membranes.
• •Chlorophyll absorbs sunlight.
• •Water molecules are split, releasing oxygen.
• •Light energy is converted into short-term chemical energy in molecules called ATP and NADPH.

• 2.The Calvin cycle
• •Occurs in the chloroplast’s stroma.
• •Uses ATP and NADPH to turn carbon dioxide into small sugar molecules.
• •These molecules can be used to make glucose, which stores energy and helps form materials such as cellulose.

Why photosynthesis matters

Photosynthesis:

• •Produces much of the oxygen in Earth’s atmosphere.
• •Provides the energy that supports most food chains.
• •Removes carbon dioxide from the air.
• •Gives plants the sugars they need for growth and cellular respiration.

A simple way to remember it is: plants use sunlight to make food from water and carbon dioxide, releasing oxygen as a byproduct.