Plant metabolism
Carbon assimilation- Photosynthesis
Practical importance- main indicators of environmental effects
and stress on plants
• Rate of photosynthesis
• Electron transport rate
• Stomata movement
• Chlorophyll content and fluorescence
Electron transport and carbon assimilation
• Electron transport and production of ATP and NADPH takes place in thylakoids.
Light reactions.
• CO2 assimilation takes place in the stroma of the chloroplast- Calvin cycle
The Calvin cycle (CBB or C3 cycle)
• Converts CO2 from air into carbohydrates needed by the plant to power its
activities
• The reactions in the Calvin cycle are powered by the ATP and NADPH formed in
the light reactions
• The Calvin cycle can be divided into three parts
○ Carboxylation - CO2 from the atmosphere is attached to RuBP (1,5
ribulose bisphosphate) , rubisco is the enzyme used in this reaction and
the final product is 2 molecules of 3PG (3 phosphoglycerate)
, • The reactions in the Calvin cycle are powered by the ATP and NADPH formed in
the light reactions
• The Calvin cycle can be divided into three parts
○ Carboxylation - CO2 from the atmosphere is attached to RuBP (1,5
ribulose bisphosphate) , rubisco is the enzyme used in this reaction and
the final product is 2 molecules of 3PG (3 phosphoglycerate)
○ Reduction- CO2 reduction by adding ATP and NADPH from the light
reactions. After a series of reactions, 3GP (triose phosphate) is made.
One molecule is transported to the cytosol for further use (sucrose
synthesis) and the other molecules of G3P move forward to the
regeneration phase
○ Regeneration - the rest of the triose phosphate molecules are turned into
ribulose bisphosphate again via series of reactions with the use of ATP.
• The Cycle has to turn 6 times to make one molecule of glucose.
• Autocatalytic cycle- allows the removal of an intermediate for synthesis a net
amount of a product without compromising the rate of regeneration of the
acceptor compound
Light harvesting process
• The capture of energy from light and its use in the synthesis of ATP and NADPH
Carbon assimilation- Photosynthesis
Practical importance- main indicators of environmental effects
and stress on plants
• Rate of photosynthesis
• Electron transport rate
• Stomata movement
• Chlorophyll content and fluorescence
Electron transport and carbon assimilation
• Electron transport and production of ATP and NADPH takes place in thylakoids.
Light reactions.
• CO2 assimilation takes place in the stroma of the chloroplast- Calvin cycle
The Calvin cycle (CBB or C3 cycle)
• Converts CO2 from air into carbohydrates needed by the plant to power its
activities
• The reactions in the Calvin cycle are powered by the ATP and NADPH formed in
the light reactions
• The Calvin cycle can be divided into three parts
○ Carboxylation - CO2 from the atmosphere is attached to RuBP (1,5
ribulose bisphosphate) , rubisco is the enzyme used in this reaction and
the final product is 2 molecules of 3PG (3 phosphoglycerate)
, • The reactions in the Calvin cycle are powered by the ATP and NADPH formed in
the light reactions
• The Calvin cycle can be divided into three parts
○ Carboxylation - CO2 from the atmosphere is attached to RuBP (1,5
ribulose bisphosphate) , rubisco is the enzyme used in this reaction and
the final product is 2 molecules of 3PG (3 phosphoglycerate)
○ Reduction- CO2 reduction by adding ATP and NADPH from the light
reactions. After a series of reactions, 3GP (triose phosphate) is made.
One molecule is transported to the cytosol for further use (sucrose
synthesis) and the other molecules of G3P move forward to the
regeneration phase
○ Regeneration - the rest of the triose phosphate molecules are turned into
ribulose bisphosphate again via series of reactions with the use of ATP.
• The Cycle has to turn 6 times to make one molecule of glucose.
• Autocatalytic cycle- allows the removal of an intermediate for synthesis a net
amount of a product without compromising the rate of regeneration of the
acceptor compound
Light harvesting process
• The capture of energy from light and its use in the synthesis of ATP and NADPH
