What are the steps of photosynthesis?

Definition

Photosynthesis is the process by which green plants, algae, and some bacteria convert light energy, usually from the sun, into chemical energy stored in glucose. The overall reaction can be summarized as:

$$ 6 \mathrm{CO}_2 + 6 \mathrm{H}_2\mathrm{O} + \text{light energy} \longrightarrow \mathrm{C}_6\mathrm{H}_{12}\mathrm{O}_6 + 6 \mathrm{O}_2 $$

Main Steps of Photosynthesis

Photosynthesis occurs in two main stages:

1. Light-dependent reactions (in the thylakoid membranes)
• Light energy is absorbed by chlorophyll.
• Water ($\mathrm{H}_2\mathrm{O}$) is split, releasing oxygen ($\mathrm{O}_2$).
• ATP and NADPH (energy carriers) are produced.
• Light-independent reactions (Calvin Cycle, in the stroma)

Worked Example

Calculate the amount of oxygen produced when 12 molecules of water are used in photosynthesis.

The simplified equation:

$$ 6 \mathrm{CO}_2 + 12 \mathrm{H}_2\mathrm{O} \longrightarrow \mathrm{C}_6\mathrm{H}_{12}\mathrm{O}_6 + 6 \mathrm{H}_2\mathrm{O} + 6 \mathrm{O}_2 $$

Step 1: Identify the number of $\mathrm{O}_2$ molecules produced per 12 $\mathrm{H}_2\mathrm{O}$:

Step 2: Calculate the number of oxygen atoms in 6 $\mathrm{O}_2$: