11.2 The light dependent reaction

Question 1

define oxidation and reduction

Answer 1

• oxidation = gain of O2, gain of H+, loss of e-
• reduction = loss of O2, loss of H+, gain of e-

Question 2

define photolysis

Answer 2

the splitting of water using light energy

Question 3

what are the products of photolysis

Answer 3

1/2 O2, 2e-, 2H+

Question 4

how does light energy become chemical energy

Answer 4

• Chlorophyll absorbs light
• pair of e- become excited and leave the chlorophyll molecule
• par of e- accepted by EC, passed down ETC by redox reactions
• lost energy used to pump H+ against conc. grad. into thylakoid
• diffuse through ATP synthase
• catalyses ADP + Pi into ATP

Question 5

describe the role of photolysis in LDR

Answer 5

• provides e- to the photoionised chlorophyll molecule
• H+ pass through ATPase
  =NADP - NADPH

Question 6

Explain adaptations of chloroplasts for LDR

Answer 6

thylakoid membranes = Large SA for chlorophyll, EC and enzymes
Proteins in grana = hold chlorophyll for max absorption
ATPase in membrane = ATP production