5.6.3 Photosynthetic Pigments

Question 1

Photosynthetic Pigments notes

Answer 1

• Chlorophyll (absorbs blue-violet and red light, reflects green)
• Carotenoids (absorbs mainly blue-violet)

Expands wavelength range that can be absorbed from light for use in photosynthesis.

Question 2

What are photosystems

Answer 2

• Thylakoids stack forming grana
• Thylakoid membrane provides large surface area for pigment molecules to absorb as much light as possible
• Pigment molecules arranged into photosystems
• In funnel like structures where each pigment molecule transfers energy down to the next until primary pigment reaction centre

2 Types

P700 or PS1 or photosystem 1 :
- Chlorophyll a has max absorption of light at 700nm
- Middle of electron transport chain

P680 or PS2 or photosystem 2 :
- Chlorophyll a in this system has max absorption of light at 680nm
- Beginning of electron transport chain, where photolysis takes place