Help With photosynthetic pigments

hey i am studying photosynthesis for ocr biology F214 module and i am stuck on photosynthetic pigments, accesory pigments, primary pigment reaction centre, and chlorophyll A and B.

could someone please explain what all those words mean and how they link together. e.g. what has chlorophyll got to do with photosynthetic pigments???

any help very much appreciated + rep if i have some spare

Chlorophyll is a group of five closely related photosynthetic pigments. The main two are chlorophyll a, chlorophyll b. There are also accessory pigments (which are also photosynthetic pigments): orange carotene, yellow xanthophyll and phaeophytin.

So essentially chlorophyll is not just one pigment - it is composed of several which absorb and capture light from different areas of the spectrum.

If you're still unsure have a read of the photosynthesis section of 'Biology Mad', although it's aimed for AQA, it can be used by all exam boards. Click on A2 Biology --> Module 5 --> Photosynthesis and respiration.

Hope that helps.

Photosynthetic pigments; are molecules that absorb light energy. Each pigment absorbs a range of wavelengths in the visible region and has its own distinct peak of absorption.

Chlorophyll is a mixture of Pigments. There are two forms of Chlorophyll A; (P680 AND P700).
These are known as the Primary Pigment reaction centre because they are found at the centre of the photo systems.

P680 is found in Photosystem II and its peak of absorption is light at a wavelength at 680 nm

P700 is found in Photosystem I and its peak of absorption is light at a wavelength of 700nm

Chlorophyll A absorbs blue light; wavelength around 450nm.
Chlorophyll B absorbs light wavelengths around 500nm - 640 nm.


Accessory pigments; they absorb light wavelengths that are not well absorbed by chlorophylls and pass the energy associated with that light to the chlorophyll A at the base of the photosystem.



This is an image of a Photosystem.

safe bro

no worries, i got this info from my notes but i find it confusing aswell. I dont know the difference between PS1 and PS2

PS2 is involved in cyclic phosphorylation where NADP is reduced to reduced NADP and water is oxidised to oxygen and hydrogen. and also adp is phosphorylated to atp. nadp is the final electron acceptor.

PS1 is involved in both cyclic and non cyclic phosphorylation. in non cyclic only atp is produced and the electrons are passed back to PS1. no nadp is reduced and no photolysis of water occurs.

Photosynthetic pigments; are molecules that absorb light energy. Each pigment absorbs a range of wavelengths in the visible region and has its own distinct peak of absorption.
Chlorophyll is a mixture of Pigments. There are two forms of Chlorophyll A; (P680 AND P700).
These are known as the Primary Pigment reaction centre because they are found at the centre of the photo systems.
P680 is found in Photosystem II and its peak of absorption is light at a wavelength at 680 nm
P700 is found in Photosystem I and its peak of absorption is light at a wavelength of 700nm
Chlorophyll A absorbs blue light; wavelength around 450nm.
Chlorophyll B absorbs light wavelengths around 500nm - 640 nm.
Accessory pigments; they absorb light wavelengths that are not well absorbed by chlorophylls and pass the energy associated with that light to the chlorophyll A at the base of the photosystem.

This is an image of a Photosystem.