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role of photosynthetic pigments
they absorb different wavelengths of light for photosynthesis
types of pigments [explain their type]
chlorophyll a [primary pigment]
chlorophyll b [accessory pigment]
carotenoids [accessory pigment]
chlorophyll a absorbs red and blue light. It reflects green light, causing leaf to appear green
location of photosynthetic pigments in a chloroplast.
-they are found in photosystems→ in the thylakoid membrane
[they are arranged in clusters called photosystems]
each photosystem contains:
-a reaction centre
-a light-harvesting system
what is a light harvesting system and its role
-contains accessory pigments that surround the reaction centre (chlorophyll a)
role
-the pigment molecules absorb light energy and transfer it to the reaction centre→ reaction centre uses this energy to excite electrons
[watch freesciencelessons]
![<p>-contains accessory pigments that surround the reaction centre (chlorophyll a)</p><p><strong>role</strong></p><p>-the pigment molecules absorb light energy and transfer it to the reaction centre→ reaction centre uses this energy to excite electrons</p><p>[watch freesciencelessons]</p>](https://knowt-user-attachments.s3.amazonaws.com/57bf0b00-e1e0-4eb3-8670-c3fe31fafd7c.png)

How is light harvested in the chloroplast membrane (5)
-pigments are in photosystem/ light-harvesting system
-pigment molecules absorb light energy
-accessory pigments absorb different wavelengths of light
-the energy is transferred from one pigment to another to the reaction centre
-the energy is used to excite electrons

2 types of photosystems and what wavelength do they each absorb light best at
Photosystem I (PSI)
-absorbs light best at a wavelength of 700nm
Photosystem II (PSII)
-absorbs light best at a wavelength of 680nm
advantage of the range of accessory pigments
-allows a range of wavelengths to be absorbed so more light energy can be absorbed
[without it, some wavelengths of light would not be absorbed. Therefore less light energy can be absorbed for photosynthesis]