Page 179 - Photosynthesis: The Green Miracle

Harun Yahya

The Formation of Photosystem I and NADPH

A photon striking Photosystem I raises a P700 chlorophyll electron to
a higher energy level. This electron is received by the NADPH line of the
electron-transfer system. Part of this energy is used to reduce the NADP+
in the stroma to NADPH. In this process, NADP+ receives two electrons
and receives one hydrogen atom from the stroma. (See the diagrams on
pages 178 and 179.)

Photosystem II – Photosystem I

The electron leaving its orbit and reaching the electron receptor and
many other subsequent processes provide the energy necessary for pho-
tosynthesis. Yet it is not enough for this process to occur only once. For
photosynthesis to continue, it must be repeated again and again. But this
suggests a major problem. When the first electron leaves its orbit, its place

remains empty. A new electron must be installed there, a subsequent pho-
ton has to strike that electron, and the electron hurled out has to be caught
by the electron receptor. There is a need for an electron to respond to the
incoming photons on every single occasion.
At this stage, a new electron to replace the one lost by the P700 is in-
stalled: The hydrogen ion (H+) in the stroma is carried inside the thylak-
oid. In Photosystem II, a photon raises energy level by striking a P680

electron. This electron passes into the other electron transfer system, re-
placing the lost electron by moving to the P700 in Photosystem I. As the
electron moves along this chain, the energy it receives from the photon is
used for carrying the hydrogen ion from the stroma to the thylakoid.
This hydrogen will later be used in the production of ATP, which all
living things use as a fuel to survive. It’s obtained with the addition of a
phosphorus atom to ADP (adenosine diphosphate, a chemical found in all
living things). In conclusion, the carrier molecules take the molecules of

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