Lecture 21: Electron Transport

Question 1

what pigment does PS2 use

Answer 1

P680+

Question 2

what is P680+

Answer 2

a very strong oxidant that is strong enough to pull electrons from H2O

Question 3

what pigment does PS1 use

Answer 3

P700

Question 4

what is P700

Answer 4

a very strong reductant that is strong enough to donate electrons to NADP+

Question 5

reductants _______ electrons to other species

Answer 5

donate

Question 6

oxidizers ______ electrons from other species

Answer 6

remove

Question 7

what does the electron transport chain generate to drive ATP production

Answer 7

proton-motive force

Question 8

which photosystem takes electron from water

Answer 8

PS2

Question 9

which photosystem donates to NADP+

Answer 9

PS1

Question 10

where are photosystems embeded

Answer 10

in thylakoid membranes

Question 11

plastoquinone

Answer 11

small molecule and mobile electron carrier that is used between PS2 and cytochrome b

Question 12

plastocyanin

Answer 12

small protein and mobile electron carrier used between cytochrome b and PS1

Question 13

what direction does the linear electron transport go

Answer 13

PS2 - Cyt b6f - PS1

Question 14

how are some chlorophylls, B-carotenes, and other small molecules held in position

Answer 14

PS2

Question 15

process of the oxygen-evolving complex

Answer 15

exciton of P680 is followed by withdrawal of one electron from Mn cluster that stores the residual positive charge. When Mn charges accumulate, the complex oxidizes 2H2O molecules and releases O2

Question 16

Electron transfer steps in PS2

Answer 16

1. light converts reaction center chlorophyll to excited form P680 - P680+
2. electron transferred to pheophytin (Pheo), forming pheo-
3. Pheo- passes electron to QA to prodcue QA-
4. passed to Qb to make Qb-

Question 17

how is the electron transferred to Q in PS2

Answer 17

Pheophytin

Question 18

electrons move from ______ to ______ side in the electron transfer of PS2

Answer 18

luminal to stromal

Question 19

first half of Q cycle in the cytochromeb6f complex

Answer 19

PQH2 delivers 2 protons to lumen and 1 electron to PC. PQ returns to PS2

Question 20

secon half of Q cycle in the cytochromeb6f complex

Answer 20

another PQH2 delivers 2 protons to lumen, and 1 electron to PC. PQ, 2 electrons, and 2 protons regenerate PQH2, which cycles again

Question 21

ferredoxin

Answer 21

a soluble electron carrier to transfer electrons to NADP+

Question 22

how does ferredoxin transfer electrons

Answer 22

ferredoxin:NADP+ reductase

Question 23

how does ATP synthase work

Answer 23

moves protons from inside of lumen to the stroma and use the movement to synthesis ATP from ADP and Pi

Question 24

where are PS2, PS1, ATP synthase, and Cyt b6f found in regions of the thylakoids

Answer 24

PS2 = appressed regions
PS1 and ATP synthase = non-appressed regions
Cyt - uniformly distributed throughout