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 Cellular RespirationLight Reaction Glycolysis

Dark Rxn (Cycle) Kreb’s Cycle

‘Glucogenesis’ Electron Transport Chain

Photosynthesis•Where do

they occur?

Photosynthesis•Reactants? Products?

P-synthesis

Reactants Products Cell.Resp.

Reactants Products

LDR Glycolysis

Dark Rxn Kreb’s Cycle

‘Glucose’ Electron Transport

Chain

NADP+, ADP, WATER, LIGHT

NADPH, CO2

Two, 3-C compounds

NADPH, ATP, Oxygen

3-C cmpd, NADP+, ADP

GLUCOSE (6-Carbons)

Glucose, ATP, NADH

3-C compound NAD+, FAD

NADH, FADH2, Oxygen

TWO, 3-C cmpds,

ADP, NAD+

NADH, FADH2,

CO2

NAD+, FAD, WATER, ENERGY

Photosynthesis•Donors? Acceptors?

P-synthesis Cellular Respiration

LDR Water – Donor NADP+ - Acceptor

Glycolysis NADH - Donor

Dark Rxn (Cycle)

NADPH – donor ‘molecule’ - accept

Kreb’s Cycle NAD+ - Acceptor

‘Glucogenesis’ Electron Transport

Chain

NADH - donor Oxygen - Acceptor

Cellular RespirationGlycolysis

Glucose

2 NAD+

“2” ATP

2 NADH

4 ATP

2 Pyruvate Acetyl- CoA

Coenzyme A CO2

Kreb’s Cycle

2-carbonsNADH

FADH2

CO2

ETC32 ATP

water

heat O2

Photosynthesis

‘Glucogenesis’

Glucose

NADP+

“2” ATP

2 NADPH

ATP

CO2

DarkRxn

3-carbons

Light Reaction

water

O2 ADP ADP

NADP+

Two3-carbon molecules

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