CARBON FIXATION

Question 1

ATP and NADPH

Answer 1

used to fix CO2

Question 2

Calvin-Benson cycle *

Answer 2

3 x RuBP
6x 3-PGA
6x G3P (1 G3P biosynthesis)
Carboxylation, reduction, regeneration

Question 3

CO2 fixation needs*

Answer 3

3 ATP and 2 NADPH (reduction)

Question 4

Ribisco

Answer 4

catalyzes the reaction between RuBP and CO2 and O2
carboxylase –> 3-PGA
oxygenase –> 3-PGA and 2-PG

Question 5

Hexadecameric form

Answer 5

8 larger subunits and 8 small subunits

Question 6

assembly of rubisco large and small subunits in the chloroplast

Answer 6

large subunit is encoded by a single gene in the chloroplast genome
small subunit is encoded by a gene in the nuclear genome
chaperones required
Rubisco activase

Question 7

regulation of rubisco activity

Answer 7

transcription –>
assembly –> chaperone proteins
reversible inhibition –> removal of sugar phosphate inhibitor by rubisco activase

Question 8

revisable inhibition

Answer 8

Carbamylated lysine
Mg
sugar phosphate inhibitor

Question 9

Lysine

Answer 9

must be carbamylated for rubisco activity

Question 10

**

Answer 10

Mn- OE complex in pSII
Fe- enzyme activity in chloroplast synthesis and electron transport in PSI
N- structure of chlorophyll
Mg- structure of chlorophyll and activation of rubisco
chlorisis

Question 11

Rubisco-mediated carboxylation of RuBP yields

Answer 11

2 3-PGA

Question 12

Autocatalytic

Answer 12

regeneration of RuBP in Calvin Benson Cycle

Question 13

Active form

Answer 13

ECM
carbamylated rubisco enzyme with MG

Question 14

Inactive from

Answer 14

ECMI
carbamylated rubsico enzyme with sugar phosphate inhibitor and Mg

Question 15

Rubisco-mediated oxygenation of RuBP yields

Answer 15

1 3-PGA (3 carbon sugar, calvin cyle)
1 2-PG (2 carbon sugar, photorespiration

Answer 16

ATP (carboxylation and reduction)
NADPH (reduction)

Question 17

CO fixation occurs in

Answer 17

chloroplast stroma