Chapter 15 (part 3)

Carbon Fixation (dark reactions)

Carbon Dioxide Fixation

Reductive Pentose Phosphate Cycle

6CO2+9ATP+5H20 9ADP+8Pi+6NADP++(DHAP or G3P)

Ribulose-1,5-Bisphosphate carboxylase/oxygenase

(rubisco)

Activation of Rubisco

Mg2+ plays role in binding and activating R 1,6-BP to accept

CO2

Rubisco Rxn Mechanisms

carboxylase

oxygenase

Reductive Pentose Phosphate Cycle

Reduction Stage

Phosphoglycerate kinase

Glyceraldehyde dehydrogenase

aldolase

F 1,6-bisphophatase

cytosol

Reductive Pentose Phosphate Cycle

Transketolases and Aldolases are used to make 5 carbon

sugars

Formation of 5 Carbon Sugars

F-6-P + 2 G3P + DHAP + 3 ATP 3 R-1,5-BP + 3 ADP

Regulation of RPP

Cycle

Thioredoxin

Oxygenase Activity of Rubisco

Photorespiration

C4 Photosynthesis

CAM Photosynthesis

stoma