3.2 Light-dependent reaction

Question 1

OIL RIG

Define Oxidation (4)
Define Reduction (4)

Answer 1

Loss of electrons, exothermic, loss of hydrogen, gain of oxygen

Gain of electrons, endothermic, gain of hydrogen loss of oxygen

Question 2

Absorption of light energy and electron transfer chain:

Process (6)

Answer 2

1. Chlorophyll molecule absorbs light energy
2. Pair of electrons become excited and move to higher energy level
3. Electrons leave, chlorophyll molecule = oxidised
4. Taken up by electron carrier molecule = reduced
5. Move down chain in series of oxidation-reduction reactions
6. Losing energy at each stage - used to combine ADP+Pi = ATP

Question 3

Photolysis:

Define photolysis

Why is it important?

OH- ions?
H+ ions?
Oxygen?

Answer 3

The splitting of water molecules into H+ ions (protons) and OH- ions (electrons) using light.

Replaces electrons lost making ATP so chlorophyll can absorb light.

= replacement electrons
= taken up by NADP, becomes NADPH, enters light- independent
= respiration/diffuses out

Question 4

Yield? (3)

Answer 4

1 ATP
NADPH
O2

Question 5

Where does it occur?

Answer 5

Thylakoids of grana