GPT on Question 12, Sep 25

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

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.

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 temporary chemical energy.

• 2.The Calvin cycle
• •Occurs in the fluid-filled part of the chloroplast called the stroma.
• •Uses carbon dioxide and the chemical energy from the first stage.
• •Produces molecules that the plant can use to build glucose and other carbohydrates.

Why photosynthesis matters

Photosynthesis:

• •Produces much of the oxygen in Earth’s atmosphere.
• •Creates food and stored energy for plants.
• •Forms the base of most food chains.
• •Removes carbon dioxide from the atmosphere.

A simple way to remember it: plants use sunlight to turn water and carbon dioxide into stored food, releasing oxygen along the way.