5.6.3 Photosynthetic Pigments

Question 1

What are photosynthetic pigments and where are they found?

Answer 1

Chloroplasts contain several different photosynthetic pigments within the thylakoids, which absorb different wavelengths of light

Question 2

What are the two types of pigments?

Answer 2

Chlorophylls and carotenoids.

Question 3

What are the names and colours of Chlorophylls?

Answer 3

Chlorophyll a- Blue-green
Chlorophyll b- Yellow-green

Question 4

What are the names and colours of Carotenoids?

Answer 4

β carotene- orange
Xanthophyll- yellow

Question 5

What do chlorophylls do?

Answer 5

Chlorophylls absorb wavelengths in the blue-violet and red regions of the light spectrum
They reflect green light, causing plants to appear green

Question 6

What do carotenoids do?

Answer 6

Carotenoids absorb wavelengths of light mainly in the blue-violet region of the spectrum

Question 7

What are photosystems?

Answer 7

The pigment molecules are arranged in light-harvesting clusters known as photosystems

Question 8

In a photosystem, how are the different pigment molecules arranged?

Answer 8

In a photosystem, the different pigment molecules are arranged in funnel-like structures in the thylakoid membrane (each pigment molecule passes energy down to the next pigment molecule in the cluster until it reaches the primary pigment reaction centre)

Question 9

Describe photosystem 1 (PSI).

Answer 9

Photosystem 1 (PSI), often referred to as P700
The chlorophyll a in this system has a maximum absorption of light at 700nm

Question 10

Describe photosystem 2 (PS11).

Answer 10

Photosystem 2 (PSII), often referred to as P680
The chlorophyll a in this system has a maximum absorption of light at 680nm