BIS 103: Photosynthesis

Question 1

evolution

Answer 1

purple + green sulfur bacteria -> cyanobacteria -> plants

Question 2

chyl A structure

Answer 2

porphyrin ring with Mg center + hyrophobic anchor

Question 3

b-carotene + xanthophyl structure

Answer 3

many conjugated bonds for different spectra of absorbance

Question 4

light reaction chemical eq (per carb)

Answer 4

H20 –> O2+ 6NADPH + 9 ATP

Question 5

life keeps NADPH and ATP in : ratio between the 2 rxns,

Answer 5

2:3 NADPH:ATP

light rxns and carbon assimilation reactions

Question 6

carbon assimilation reaction chemical eq (per carb)

Answer 6

3 CO2 –> 1-glyceraldehyde-3-P + 6 NADP+ + ADP

Question 7

experiment to measure productivity

Answer 7

have prism between light and micro slide of algae

let bacteria free - chemotaxis to high O2 (produced from photosynthesis)

Question 8

modern data of photosynthesis productivity uses

Answer 8

O2 electrode

Question 9

chloroplast structure - rxns in

Answer 9

outer and thylakoid membrane -light rxns
stroma - calvin cycle
Ribosomes - 20% of DNA

Question 10

reaction center - structure, function

Answer 10

2 chyl molecules perfectly oriented, act as 1 - excite e-

separates charge - lets e- flow

Question 11

antenna molecules: name, fxn

Answer 11

antenna chlorophylls and carotenoids

exiton transfer between molecules until it hits rxn center`

Question 12

purple sulfur bacteria mechanism

Answer 12

1. exiton transfer to excite pigment
2. e- passes to pheo + plastoquinone
3. e- to cyt complex to make H+ gradient
4. cyt returns e-

Question 13

purple sulfur bacteria use which pigment?

Answer 13

p870

Question 14

green sulfur bacteria use which pigment?

Answer 14

p840

Question 15

currents use which pigment?

Answer 15

P680 then P700

Question 16

green sulfur bacteria mechanism

Answer 16

1. exiton transfer to excite pigment
2. e- passes to (no Pheo) + plastoquinone
3. e- to cyt complex to make H+ gradient
4. cyt returns e-

OR- NADH

Question 17

difference between green and purple bacteria mech

Answer 17

• no Pheo
• no optional synthesis of NADH
• different pigment - less ground state energy for green

Question 18

photosystem I and II are from :

Answer 18

g sulfur (2nd) and purple (1st)

Question 19

how many photons per NADPH?

Answer 19

4

Question 20

most hungry for H2O’s e- is

Answer 20

P680+ - most positive E*’