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Transcript of Photosynthesis is an anabolic process that combines carbon dioxide and water in the presence of...
Chapter 10Plant metabolism -
photosynthesis
Photosynthesis
Photosynthesis is an anabolic process that combines carbon dioxide and water in the presence of light with the aid of chlorophyll and transforms the energy from the sun to biochemical energy in the bonds between the atoms in a sugar molecule; oxygen is a by-product.
Photosynthesis
Photosynthesis is an anabolic process that combines carbon dioxide and water in the presence of light with the aid of chlorophyll and transforms the energy from the sun to biochemical energy in the bonds between the atoms in a sugar molecule; oxygen is a by-product.
C-source
Global warming
Photosynthesis
Photosynthesis is an anabolic process that combines carbon dioxide and water in the presence of light with the aid of chlorophyll and transforms the energy from the sun to biochemical energy in the bonds between the atoms in a sugar molecule; oxygen is a by-product.
Isotope
Sole source of O2
Photosynthesis
Photosynthesis is an anabolic process that combines carbon dioxide and water in the presence of light with the aid of chlorophyll and transforms the energy from the sun to biochemical energy in the bonds between the atoms in a sugar molecule; oxygen is a by-product.
P680P700
Photosynthesis
Photosynthesis is an anabolic process that combines carbon dioxide and water in the presence of light with the aid of chlorophyll and transforms the energy from the sun to biochemical energy in the bonds between the atoms in a sugar molecule; oxygen is a by-product.
Photosynthesis
… transforms the energy from the sun to biochemical energy in the bonds between the atoms in a sugar molecule; oxygen is a by-product.
ADPNADP
ATPNADPH
Ele
ctro
n fl
ow(Z
sch
eme)
H2O
O2
Calvin cycle
CO2 RuBP
Light-dependent reaction
Light-independent reactionCarbon-fixing and reducing reaction
Photosynthesis
Water molecules are split, releasing e-, H+, and O2
e- passing along electron transport system
H+ is involved in NADP to form NADPH
ATP molecules are produced
ADPNADP
ATPNADPH
Z s
chem
e
H2O
O2
Light-dependent reaction
Photosynthesis
Water molecules are split, releasing e-, H+, and O2
Light-dependent reaction
Photosynthesis
Water molecules are split, releasing e-, H+, and O2
Electron flow: e- passing along electron transport
system
Light-dependent reaction
Z scheme
Photosynthesis
Water molecules are split, releasing e-, H+, and O2
e- passing along electron transport system
H+ is involved in NADP to form NADPH
Light-dependent reaction
Photosynthesis
Water molecules are split, releasing e-, H+, and O2
e- passing along electron transport system
H+ is involved in NADP to form NADPH
ATP molecules are produced
Light-dependent reaction
Photophosphorylation
Photosynthesis
… transforms the energy from the sun to biochemical energy in the bonds between the atoms in a sugar molecule; oxygen is a by-product.
ADPNADP
ATPNADPH
Ele
ctro
n fl
ow(Z
sch
eme)
H2O
O2
Calvin cycle
CO2 RuBP
Light-dependent reaction
Light-independent reactionCarbon-fixing and reducing reaction
Photosynthesis
Water
Light-independent reaction
Calvin cycle
Photosynthesis
Carboxylation
Light-independent reaction
Calvin cycle
6 CO2 + 6 RuBPRubisco(RuBP carboylase/oxygenase)
12 3PGA
Photosynthesis
Carboxylation Reduction
Light-independent reaction
Calvin cycle
6 CO2 + 6 RuBPRubisco(RuBP carboylase/oxygenase)
12 3PGA
12 GA3P
Photosynthesis
Carboxylation Reduction Regeneration
Light-independent reaction
Calvin cycle
6 CO2 + 6 RuBPRubisco(RuBP carboylase/oxygenase)
12 3PGA
10 GA3P
6 RuBP
2 GA3P+
Photosynthesis
Photosynthesis vs. photorepiration Stomata are closed under hot and dry climates, which
leads to a decreased CO2:O2 ratio and hence promote photorespiration
How to inhibit photorespiration and hence promote fixation of CO2
ADPNADP
ATPNADPH
Ele
ctro
n fl
ow(Z
sch
eme)
H2O
O2
Calvin cycle
CO2 RuBP
Photo-respiration
Photosynthesis vs. photorepiration
How to inhibit photorespiration and hence promote fixation of CO2
Calvin cycle
CO2 RuBP
Photo-respiration
Photosynthesis vs. photorepiration
Increasing CO2:O2 ratio
CO2 are combined with PEP (a 3-carbon compound), producing
OAA (a 4-carbon compound) in mesophyll cells The 4-carbon compounds are transported to the bundle sheath cells
where CO2 are released, concentrated and enter the Calvin cycle.
Photosynthesis: the 4-Carbon pathway
Mesophyll cells: CO2 + PEP → OAA Bundle sheath cells: 4-C → CO2 → Calvin cycle.
Photosynthesis: the 4-Carbon pathway
Kranz anatomy leave
How to inhibit – C4 photosynthesis
ADPNADP
ATPNADPH
Ele
ctro
n fl
ow(Z
sch
eme)
H2O
O2
Calvin cycle
CO2 RuBP
Photo-respiration
Photosynthesis vs. photorepiration
Mesophyll cell
- OAA
BSC – concentrated
CO2
Night: CO2 + PEP → OAA → malic acid
accumulating organic acids in vacuole Day: 4-C → CO2 → Calvin cycle
releasing CO2 in mesophyll cell
Photosynthesis: CAM pathway
ADPNADP
ATPNADPH
Ele
ctro
n fl
ow(Z
sch
eme)
H2O
O2
Calvin cycle
CO2 RuBP
Photo-respiration
Photosynthesis
Mesophyll cell
- OAA
BSC – concentrated
CO2
Night – accumulating organic acids in vacuole
Day – concentrated CO2 in mesophyll cell
C3 plantC4 plantCAM plant