Chapter 10

Photosynthesis

Cellular respiration:

C6H12O6 + 6O2 + 6H2O 6CO2 + 12H2O +

Chapter 10

Photosynthesis

Photosynthesis:

C6H12O6 + 6O2 + 6H2O 6CO2 + 12H2O +

Chapter 10

Photosynthesis

Photosynthesis:

C6H12O6 + 6O2 + 6H2O 6CO2 + 12H2O +

H2O is oxidized

CO2 is reduced

Chapter 10

Photosynthesis

Chapter 10

Photosynthesis

chloroplast

Chapter 10

Photosynthesis

chloroplast thylakoid

chloroplast thylakoid

granum

Chapter 10

Photosynthesis

Chapter 10

Photosynthesis

Chapter 10

Photosynthesis

intermembrane space

stroma

lumen

Chapter 10

Photosynthesis

intermembrane space

stroma NOT STOMA!!

lumen

Chapter 10

Photosynthesis

Chapter 10

Photosynthesis

Chapter 10

Photosynthesis

Chapter 10

Photosynthesis

PS II

PS ICalvincycle

ET

C

ET

C

Chapter 10

Photosynthesis

PS II

PS ICalvincycle

ET

C

ET

C

Chapter 10

Photosynthesis

PS II

PS ICalvincycle

ET

C

ET

C

Chapter 10

Photosynthesis

PS II

PS ICalvincycle

H2O

O2E

TC

ET

C

Chapter 10

Photosynthesis

PS II

PS ICalvincycle

H2O

O2E

TC

ET

C

H+

Chapter 10

Photosynthesis

PS II

PS ICalvincycle

H2O

O2E

TC

ET

CATP

H+

Chapter 10

Photosynthesis

PS II

PS ICalvincycle

H2O

O2E

TC

ET

CATP

H+

Chapter 10

Photosynthesis

PS II

PS ICalvincycle

H2O

O2E

TC

ET

CATP

H+

Chapter 10

Photosynthesis

PS II

PS ICalvincycle

H2O

O2E

TC

ET

CATP

NADH

H+

Chapter 10

Photosynthesis

PS II

PS I

H2O

O2E

TC

ET

CATP

NADH

H+

Calvincycle

Chapter 10

Photosynthesis

PS II

PS I

H2O

O2E

TC

ET

CATP

NADH

CO2

glucoseH+

Calvincycle

•photon

•energizes light harvesting complex

•energizes P680 chlorophyll

•releases e- to primary acceptor

•water is split to replace e-, releasing H+

•e- is passed to ETC (Pq, cytochromes, Pc)

•ETC makes ATP and brings in more H+.

Chapter 10

Photosynthesis

Photo System II:

•photon

•energizes light harvesting complex

•energizes P700 chlorophyll

•releases e- to primary acceptor

•ETC replaces e-

•e- is passed to next ETC (ferredoxin)

•NADP+ reductase makes NADPH.

Chapter 10

Photosynthesis

Photo System I:

•just like in the mitochondria

Chapter 10

Photosynthesis

Chemiosmosis:

In the stroma

Chapter 10

Photosynthesis

Calvin cycle:

RuBP carboxylase (rubisco)

PCCCCCP

PCCCCCP

PCCCCCP

Chapter 10

Photosynthesis

phase I: carbon fixationCO2 CO2 CO2

CO2 CO2 CO2

PCCCCCP

PCCCCCP

PCCCCCP

Chapter 10

Photosynthesis

phase I: carbon fixation

PCCCCCCP

PCCCCCCP

PCCCCCCP

Chapter 10

Photosynthesis

phase I: carbon fixation

PCCCCCCP

PCCCCCCP

PCCCCCCP

Chapter 10

Photosynthesis

phase I: carbon fixation

not yet glucose

PCCC CCCP

PCCC CCCP

PCCC CCCP

Chapter 10

Photosynthesis

phase I: carbon fixation

PCCC CCCP

PCCC CCCP

PCCC CCCP

Chapter 10

Photosynthesis

phase II: reductionATP ATP ATP ATP ATP ATP

PCCC CCCP

PCCC CCCP

PCCC CCCP

Chapter 10

Photosynthesis

phase II: reductionATP ATP ATP ATP ATP ATP

ADP ADP ADP ADP ADP ADP

PCCCP PCCCP

PCCCP PCCCP

PCCCP PCCCP

Chapter 10

Photosynthesis

phase II: reduction

ADP ADP ADP ADP ADP ADP

PCCCP PCCCP

PCCCP PCCCP

PCCCP PCCCP

Chapter 10

Photosynthesis

phase II: reduction

PCCCP PCCCP

PCCCP PCCCP

PCCCP PCCCP

Chapter 10

Photosynthesis

phase II: reductionNADPH NADPH NADPH NADPH NADPH NADPH

PCCCP PCCCP

PCCCP PCCCP

PCCCP PCCCP

Chapter 10

Photosynthesis

phase II: reductionNADPH NADPH NADPH NADPH NADPH NADPH

NADP+ NADP+ NADP+ NADP+ NADP+ NADP+

CCCP CCCP

CCCP CCCP

CCCP CCCP

Chapter 10

Photosynthesis

phase II: reduction

This is now

glyceraldehyde-3-phosphate (G3P)

CCCP CCCP

CCCP CCCP

CCCP CCCP

Chapter 10

Photosynthesis

phase II: reduction

CCCP CCCP

CCCP CCCP

CCCP CCCP

Chapter 10

Photosynthesis

phase III: regeneration of RuBP

CCCP

CCCP

CCCP

CCCP

CCCP CCCP

Chapter 10

Photosynthesis

phase III: regeneration of RuBP

CCCP

CCCP

CCCP

CCCP

CCCP CCCP

Chapter 10

Photosynthesis

phase III: regeneration of RuBPATP ATP ATP

CCCP

CCCP

CCCP

CCCP

CCCP CCCP

Chapter 10

Photosynthesis

phase III: regeneration of RuBPATP ATP ATP

ADP ADP ADP

PCCCCCP

PCCCCCP

PCCCCCP CCCP

Chapter 10

Photosynthesis

phase III: regeneration of RuBP

Back to the Calvin cycle

PCCCCCP

PCCCCCP

PCCCCCP CCCP

Chapter 10

Photosynthesis

phase III: regeneration of RuBP

Half a sugar molecule

PCCCCCP

PCCCCCP

PCCCCCP CCCP

Chapter 10

Photosynthesis

phase III: regeneration of RuBP

•Rubisco can bind to O2 if there isn’t enough CO2

•Wastes energy

•Evolutionary relic.

Chapter 10

Photosynthesis

Photorespiration

•Adaptation to dry conditions

•PEP carboxylase

•pyruvate → oxaloacetate

•Corn and other grasses.

Chapter 10

Photosynthesis

C4 versus C3

Chapter 10

Photosynthesis

C4 versus C3

•Crassulacian acid metabolism

•Carbon fixation at night

•Cacti, jade, pineapple.

Chapter 10

Photosynthesis

CAM