Photosynthesis

Section 8.2

Photosynthesis

• The process by which plants convert light energy into chemical energy in the form of carbohydrate (sugar).

• 6CO2 + 6H2O →Light Energy (sun)→ C6H12O6 + 6O2

2 Stages of Photosynthesis• Occurs in a plant’s chloroplast which is GREEN.

• The green pigment’s name is chlorophyll.

• Takes place in Two Stages.

Stage 1: The Light-Dependent Reactions

• Light strikes chlorophyll, energizing an electron.

• The high energy electron moves through a series of reactions called an electron transport chain.

• The electron transport chain makes ATP and NADPH for the next stage.

• Water breaks down– The H replaces the one lost by chlorophyll– The O2 is released as gas

Stage 2: Light-Independent Reactions

• CO2is absorbed by the leaves.• ATP and NADPH (from the light reactions)

donate their electrons.• The electrons combine carbons from the CO2

in a series of reactions to eventually make one glucose molecule.

• SWEET!

Photosynthesis - Recap