Photosynthesis: energy- and carbon-capture

Question 1

In what ways can electrons return to their ground state?

Answer 1

Releasing energy via:
- florescence
(emit light at higher wavelengths than absorbed

• resonance
  (transfer vibration energy to nearby molecules)
• electron transfer
  (excited electron is transferred to an acceptor molecule)

Question 2

What is the function of the antenna complex of photosystems?

Answer 2

funnel excited electrons to the photochemical reaction centre by resonance transfer/ florescence.

there it is used to promote charge separation

Question 3

What do cyanobacteria have instead of an antenna complex?

Answer 3

Phycobilisome

• embedded with Bilin instead of chlorophyll

Question 4

What are the three different bilin pigments

Answer 4

Phycocyanin (PC)

Phycoerythrin (PE)

Allophycocyanin (APC)

each with different light absorbing properties

Question 5

How do the different bilin pigments work together?

Answer 5

PE:

• absorbs green light
• remits it as orange light

PC:

• absorbs orange light
• remits it as red light

APC:

• absorbs red light
• remits it at the exact wavelength of light need by chlorophyll