PHOTOPHOSPHORYLATION

Question 1

Photophosphorylation

Answer 1

to make ATP during the photosynthesis in chloroplasts
energy source –> light from the sun
electron source –> H2O
proton accumulation –> thylakoid space
movement of protons –> out of the thylakoid space

Question 2

Linear electron transport

Answer 2

electrons transferred from H2O to NADPH
PSII, Cyc b6f and PSI
products: ATP and NADPH

Question 3

cyclic electron transport

Answer 3

flow of electron from PSI to Cyt b6f
no NADPH generation
product: ATP
regulation

Question 4

Water-water cycle

Answer 4

product: ATP
electrons transferred from H2O to H2O
PSII, Cyt b6f, and PSI

Question 5

Proton motive force

Answer 5

energy of the proton concentration gradient
pH difference between lumen and stroma

Question 6

excess excitation energy

Answer 6

can lead to photo-oxidative damage
Triplet excited chlorophyll

Question 7

excess light energy

Answer 7

is dissipated via non-photochemical quenching

Question 8

Energy-dependent quenching

Answer 8

PSII
Low light: less activity (less concentration of H+) high luminal pH
Vioalaxanthin __> Zeaxanthin (rearrangement of LCHII and reaction center II)
Dissipation of light energy as heat

Question 9

State transition

Answer 9

accumulation of PQH2 activates LCHII kinase
LCHII phosphorylation–> prevents the energy transfer to PSII

Question 10

Photoinhibition

Answer 10

D1 protein of PSII is susceptible to photodamage: photosynthesis is inhibited