Page 120 - Demo 1

Figure 53
Source: http://alevelnotes.com/content_images/chloroplast.gif

Photosynthesis depends on an interacon between two sets of
reacons: the light reacons and the Calvin cycle.
THE LIGHT REACTIONS

The following reacons take place in the thylakoid membrane during the
light reacons:

• Chlorophyll within the thylakoid membranes absorbs solar
energyand energizes electrons
• Water is oxidized, releasing hydrogen ions (H+), and oxygen

• ATP is produced from ADP + Pi with the help of an electron
transportchain

• NADP+, an enzyme helper, accepts electrons and becomes NADPH

The light reacons use light energy to make two molecules needed for
the next stage of photosynthesis: the energy storage molecule ATP and the

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