● In `color{violet}"photosystem II,"` the reaction centre `color{violet}"chlorophyll a absorbs 680 nm"` wavelength of `color{violet}"red light"` causing `color{violet}"electrons to become excited"` and jump into an orbit farther from the atomic nucleus.
● These electrons are `color{violet}"picked up by an electron acceptor"` which passes them to an `color{Brown}"electrons transport system"` consisting of `color{violet}"cytochromes"`.
● This movement of `color{violet}"electrons is downhill,"` in terms of an `color{violet}"oxidation-reduction"` or `color{violet}"redox potential scale"`.
● The `color{violet}"electrons are not used up"` as they pass through the electron transport chain, but are `color{violet}"passed on to the pigments"` of `color{violet}"photosystem PS I"`.
● Simultaneously, electrons in the `color{violet}"reaction centre of PS I"` are also excited when they receive `color{violet}"red light of wavelength 700 nm"` and are transferred to another `color{violet}"accepter molecule"` that has a `color{violet}"greater redox potential"`.
● These electrons then are `color{violet}"moved downhill again"`, this time to a molecule of `color{violet}"energy-rich"` `NADP^+`.
● The `color{violet}"addition of these"` `color{violet}"electrons reduces"` `NADP^+` to `NADPH` + `H^+`.
● This `color{violet}"whole scheme"` of `color{violet}"transfer of electrons,"`
starting from the PS II, uphill to the acceptor,
down the electron transport chain to PS I,
excitation of electrons, transfer to another accepter, and finally down hill to `NADP^+`
causing it to be reduced to `NADPH` + `H^+`. is called the `color{Brown}"Z scheme"`, due to its characterstic shape.
● This shape is formed when `color{violet}"all the carriers"` are placed in a `color{violet}"sequence"` on a `color{violet}"redox potential scale"`.
● In `color{violet}"photosystem II,"` the reaction centre `color{violet}"chlorophyll a absorbs 680 nm"` wavelength of `color{violet}"red light"` causing `color{violet}"electrons to become excited"` and jump into an orbit farther from the atomic nucleus.
● These electrons are `color{violet}"picked up by an electron acceptor"` which passes them to an `color{Brown}"electrons transport system"` consisting of `color{violet}"cytochromes"`.
● This movement of `color{violet}"electrons is downhill,"` in terms of an `color{violet}"oxidation-reduction"` or `color{violet}"redox potential scale"`.
● The `color{violet}"electrons are not used up"` as they pass through the electron transport chain, but are `color{violet}"passed on to the pigments"` of `color{violet}"photosystem PS I"`.
● Simultaneously, electrons in the `color{violet}"reaction centre of PS I"` are also excited when they receive `color{violet}"red light of wavelength 700 nm"` and are transferred to another `color{violet}"accepter molecule"` that has a `color{violet}"greater redox potential"`.
● These electrons then are `color{violet}"moved downhill again"`, this time to a molecule of `color{violet}"energy-rich"` `NADP^+`.
● The `color{violet}"addition of these"` `color{violet}"electrons reduces"` `NADP^+` to `NADPH` + `H^+`.
● This `color{violet}"whole scheme"` of `color{violet}"transfer of electrons,"`
starting from the PS II, uphill to the acceptor,
down the electron transport chain to PS I,
excitation of electrons, transfer to another accepter, and finally down hill to `NADP^+`
causing it to be reduced to `NADPH` + `H^+`. is called the `color{Brown}"Z scheme"`, due to its characterstic shape.
● This shape is formed when `color{violet}"all the carriers"` are placed in a `color{violet}"sequence"` on a `color{violet}"redox potential scale"`.