Photosynthesis
• Compare and Contrast to Cellular
Respiration
• In what order are the reactions?
• Where do they occur?
• Reactants? Products?
• Electron acceptors and ‘donors’?
Photosynthesis
• In what order are the reactions?
Photosynthesis
Light Reaction
Cellular Respiration
Glycolysis
Dark Rxn (Cycle)
Kreb’s Cycle
‘Glucogenesis’
Electron Transport
Chain
Photosynthesis
• Where do
they occur?
Photosynthesis
• Reactants? Products?
Psynthesis
Reactants
Products
Cell.
Resp.
Reactants
Products
LDR
NADP+, ADP,
WATER,
LIGHT
NADPH, ATP,
Oxygen
Glycolysis
Glucose,
ATP, NADH
TWO, 3-C
cmpds,
ADP, NAD+
NADPH, CO2
3-C cmpd,
NADP+, ADP
Kreb’s
Cycle
3-C
compound
NAD+, FAD
NADH,
FADH2,
CO2
GLUCOSE
(6-Carbons)
Electron
Transport
Chain
NADH,
FADH2,
Oxygen
NAD+, FAD,
WATER,
ENERGY
Dark Rxn
‘Glucose’
Two, 3-C
compounds
Photosynthesis
• Donors? Acceptors?
P-synthesis
Cellular
Respiration
Glycolysis
Water – Donor
NADH - Donor
NADP+ - Acceptor
Dark Rxn
NADPH – donor Kreb’s Cycle NAD+ - Acceptor
(Cycle)
‘molecule’ - accept
‘Glucogenesis’
Electron
NADH - donor
Transport
Oxygen Chain
Acceptor
LDR
Glycolysis
2 NAD+
Cellular Respiration
2 NADH
Coenzyme A
2 Pyruvate
Glucose
“2” ATP
4 ATP
32 ATP
ETC
Acetyl- CoA
Kreb’s
Cycle
NADH
water
FADH2
heat
CO2
O2
CO2
2-carbons
Photosynthesis
Light Reaction
NADP+
CO2
NADP+
2 NADPH
Dark
Rxn
water
ATP
ADP
O2
‘Glucogenesis’
Glucose
ADP
“2” ATP
Two
3-carbon molecules
3-carbons
Leaves and P-syn
• Need to open
‘stomates’to let CO2 in
• Water will go from…
• So plant will lose water
• Will dry in drought
Drought Adaptations
• In photosynthesis (C3), plants take in
CO2 right to the Dark Reaction
• C4 – uses an intermediate, instead of
taking in CO2 ‘directly’
Takes ATP!!!!
C4 – drought resistant
• Rice is the world’s major grain
• Half the world’s staple
• It’s a C3 plant
• If ‘you’ could genetically engineer it to be
a C4 plant…
C4 – drought resistant
In prolonged drought (desert) situations
an alternative is needed
• In the desert, what part of day is hottest,
driest?
• What would be the best time of day to be
“open” to get CO2?
• CAM plants do this
Crassulacean Acid
Metabolism
CAM
CAM – desert resistant
• ‘Fix’ CO2 during the night and save for
daylight
• LDR with CO2 captured at night
• Costly for the plant, but it’s better than
dying
CAM – desert resistant
Homework
• Answer to Obj 14
• Review for Final