Chapter 10.3.1 (Exam 2) Calvin Cycle Flashcards
Chemical Energy Trapped in Photosynthesis Is Used to Synthesize Carbohydrates
What happens in carbon fixation?
CO2 is reduced to carbohydrates
What is the carbon fixation pathway?
The Calvin cycle
Where does the Calvin cycle occur?
In the stroma
Where does the energy used to reduce CO2 into carbohydrates come from?
ATP and NADPH
Explain how the fixation of CO2 into 3PG occurs.
CO2 binds to 5-C RuBP, catalyzed by ribulose bisphosphate carboxylase/oxygenase (rubisco)
The 6-C compound immediately breaks down into two molecules of 3PG, 3-Phosphoglycerate (first product)
What are the 3 main steps in the Calvin cycle?
Fixation of CO2 to 3PG
Reduction of 3PG to G3P (triose phosphate)
Regeneration of RuBP, the CO2 acceptor
From 6 CO2, 12 3PG are formed. From 12 3PG, 12 G3P are formed. How are the 12 G3P used?
2 G3P go toward the formation of sugars and carbon compounds
The 10 remaining G3P go to the regeneration of RuBP
What is the fate of the 2 G3P that leave the Calvin cycle?
Exported to the cytoplasm where it is converted to glucose & fructose
Used to synthesize glucose and starch within the chloroplast
What is the product of the Calvin cycle?
Glyceraldehyde 3-phosphate (G3P)
What is the glucose and fructose made from G3P used in?
Respiration
Converted to sucrose and transported to other parts of the plant for energy or to build other molecules
What is the glucose and starch made in the chloroplast from G3P used for?
The stored starch is used at night so that photosynthetic tissues can continue to export sucrose to the rest of the plant
