Electron Flow in Light Reaction Flashcards
These are the functional units for photosynthesis
Photosystems
Where are photosystems found?
Thylakoid membranes
They are characterized by a particular pigment organization and association patterns whose work is the absorption and transfer of light energy, which implies transfer of electrons
Photosystems
What are the two types of Photosystems
Photosystem I and Photosystem II
These are light harvesting complex made up of 250-400 pigment molecules, accessory pigments and associated proteins.
Photosystems
Where can photosystems be found?
Thylakoid membrane
To be more specific, where can the photosystems be found on plants and algae?
The thylakoid membrane of the chloroplast
To be more specific, where can the photosystems be found on photosynthetic bacterias?
Cell membrane of photosynthetic bacterias
What are the two functions of photosystems?
-Absorbing light energy
- Transfer of energy and electrons
This is the site of dependent reactions
Thylakoid membrane
The enzyme NADP reductase then transfers electrons from ferredoxin to NADP+, generating what?
NADPH
Each photosystem consists of two closely linked components, what are these?
- Reaction Centre
- Antenna Molecules
This type of photosystem have maximum absorption at 700nm or far red region or photocentre is P700
-Pigments absorbs long wavelengths of light
Photosystem I
This type of photosysyem has an iron-sulphur (FeS) type reaction centre
Photosystem 1
This type of photosystem is rich in chlorophyll-a
Photosystem I
This type of photosystem does not act as a proton pump; instead, it uses these high-energy electrons to reduce NADP+ to NADPH.
Photosystem I
What are used to produce ATP?
Hydrogen ions
This type of photosystem have maximum absorption at 680 nm or red region or photocentre is 680
Photosystem II
This type of photosystem have pigments that absorbs shorter wavelengths of light
Photosystem II
This type of photosystem is rich in chlorophyll-b
Photosystem II
What are the two possible ways for electron flow
Cyclic and Non-cyclic phosphorylation
In this way of electron flow, only PS I is involved
Cyclic phosphorylation
It is a process which results in the movement of electrons in a cyclic manner to produce ATP.
Cyclic phosphorylation
This way of electron flow happens in the thylakoid membrane which uses photosystem I and the chlorophyll P700.
Cyclic phosphorylation
When light is absorbed in PS I, where does the excited electrons enter to produce ATP from ADT + Pi?
Electron Transport Chain
What happens to the excited electrons as it enters the Electron Transport Chain?
It loses its energy
when the electron loses its energy as it enters the Electron Transport Chain, where does it go to restore its energy?
Photosystem I
In this way of Electron flow, PS I and PS II are involved
Non-cyclic Phosphorylation
In this way of electron flow, ATP is produced that will be used as energy needed for the Calvin cycle.
Non-cyclic Phosphorylation
Why is it called Non-cyclic Phosphorylation?
because, the loss of electrons in P680 in photosystem II are occupied by P700 in photosystem I and are not returned to P680.
