Figure 10-01

LE 10-2 Plants Unicellular protist Purple sulfur bacteria 10 µm Purple sulfur bacteria 1.5 µm Multicellular algae Cyanobacteria 40 µm

LE 10-2a Plants

LE 10-2b Multicellular algae

LE 10-2c Unicellular protist 10 µm

LE 10-2d Cyanobacteria 40 µm

LE 10-2e Purple sulfur bacteria 1.5 µm

LE 10-3 Leaf cross section Vein Mesophyll Stomata CO2 O2 Mesophyll cell Chloroplast 5 µm Outer membrane Thylakoid Stroma Granum Thylakoid space Intermembrane space Inner membrane 1 µm

LE 10-4 Reactants: 6 CO2 12 H2O Products: C6H12O6 6 H2O 6 O2

LE 10-5_1 H2O Light LIGHT REACTIONS Chloroplast

LIGHT REACTIONS ATP NADPH O2 LE 10-5_2 H2O Light LIGHT REACTIONS ATP NADPH Chloroplast O2

H2O CO2 Light NADP+ ADP + CALVIN CYCLE LIGHT REACTIONS ATP NADPH Chloroplast [CH2O] (sugar) O2

1 m (109 nm) 10–5 nm 10–3 nm 1 nm 103 nm 106 nm 103 m Gamma rays LE 10-6 1 m (109 nm) 10–5 nm 10–3 nm 1 nm 103 nm 106 nm 103 m Gamma rays Micro- waves Radio waves X-rays UV Infrared Visible light 380 450 500 550 600 650 700 750 nm Shorter wavelength Longer wavelength Higher energy Lower energy

Light Reflected light Chloroplast Absorbed Granum light Transmitted

Slit moves to pass light of selected wavelength Green light LE 10-8a White light Refracting prism Chlorophyll solution Photoelectric tube Galvanometer 100 The high transmittance (low absorption) reading indicates that chlorophyll absorbs very little green light. Slit moves to pass light of selected wavelength Green light

Slit moves to pass light of selected wavelength LE 10-8b White light Refracting prism Chlorophyll solution Photoelectric tube 100 Slit moves to pass light of selected wavelength The low transmittance (high absorption) reading indicates that chlorophyll absorbs most blue light. Blue light

Absorption of light by chloroplast pigments LE 10-9a Chlorophyll a Chlorophyll b Carotenoids Absorption of light by chloroplast pigments 400 500 600 700 Wavelength of light (nm) Absorption spectra

synthesis (measured Rate of photo- by O2 release) LE 10-9b synthesis (measured Rate of photo- by O2 release) Action spectrum

Engelmann’s experiment LE 10-9c Aerobic bacteria Filament of algae 400 500 600 700 Engelmann’s experiment

“head” of molecule; note magnesium atom at center CH3 in chlorophyll a CHO in chlorophyll b Porphyrin ring: light-absorbing “head” of molecule; note magnesium atom at center Hydrocarbon tail: interacts with hydrophobic regions of proteins inside thylakoid membranes of chloroplasts; H atoms not shown

Excitation of isolated chlorophyll molecule Fluorescence Excited state e– Heat Energy of electron Photon (fluorescence) Photon Ground state Chlorophyll molecule Excitation of isolated chlorophyll molecule Fluorescence

Excitation of isolated chlorophyll molecule LE 10-11a Excited state e– Heat Energy of electron Photon (fluorescence) Photon Ground state Chlorophyll molecule Excitation of isolated chlorophyll molecule

LE 10-11b Fluorescence

(INTERIOR OF THYLAKOID) LE 10-12 Thylakoid Photosystem STROMA Photon Light-harvesting complexes Reaction center Primary electron acceptor Thylakoid membrane e– Transfer of energy Special chlorophyll a molecules Pigment molecules THYLAKOID SPACE (INTERIOR OF THYLAKOID)

LE 10-13_1 Primary acceptor e– Energy of electrons Light P680 H2O CO2 Light NADP+ ADP LIGHT REACTIONS CALVIN CYCLE ATP NADPH O2 [CH2O] (sugar) Primary acceptor e– Energy of electrons Light P680 Photosystem II (PS II)

LE 10-13_2 Primary acceptor H2O e– 2 H+ + O2 1/2 Energy of electrons CO2 Light NADP+ ADP LIGHT REACTIONS CALVIN CYCLE ATP NADPH O2 [CH2O] (sugar) Primary acceptor H2O e– 2 H+ + 1/2 O2 e– e– Energy of electrons Light P680 Photosystem II (PS II)

LE 10-13_3 Primary Electron transport chain acceptor Pq H2O e– CO2 Light NADP+ ADP LIGHT REACTIONS CALVIN CYCLE ATP NADPH O2 [CH2O] (sugar) Primary acceptor Electron transport chain Pq H2O e– Cytochrome complex 2 H+ + 1/2 O2 e– Pc e– Energy of electrons Light P680 ATP Photosystem II (PS II)

LE 10-13_4 Primary acceptor Primary Electron transport chain acceptor H2O CO2 Light NADP+ ADP LIGHT REACTIONS CALVIN CYCLE ATP NADPH O2 [CH2O] (sugar) Primary acceptor Primary acceptor Electron transport chain Pq e– H2O e– Cytochrome complex 2 H+ + 1/2 O2 e– Pc e– P700 Energy of electrons Light P680 Light ATP Photosystem I (PS I) Photosystem II (PS II)

LE 10-13_5 ADP Electron Transport chain Primary acceptor Primary H2O CO2 Light NADP+ ADP LIGHT REACTIONS CALVIN CYCLE ATP NADPH O2 Electron Transport chain [CH2O] (sugar) Primary acceptor Primary acceptor Electron transport chain Fd Pq e– e– H2O e– e– NADP+ Cytochrome complex 2 H+ NADP+ reductase + 2 H+ + 1/2 O2 NADPH Pc e– + H+ Energy of electrons e– P700 Light P680 Light ATP Photosystem I (PS I) Photosystem II (PS II)

NADPH Mill makes ATP Photosystem II Photosystem I e– ATP e– e– e– e– LE 10-14 e– ATP e– e– NADPH e– e– e– Mill makes ATP Photon e– Photon Photosystem II Photosystem I

Primary acceptor Primary Fd acceptor Fd NADP+ Pq NADP+ reductase LE 10-15 Primary acceptor Primary acceptor Fd Fd NADP+ Pq NADP+ reductase Cytochrome complex NADPH Pc Photosystem I ATP Photosystem II

Electron transport chain Mitochondrion Chloroplast MITOCHONDRION STRUCTURE CHLOROPLAST STRUCTURE H+ Diffusion Intermembrane space Thylakoid space Electron transport chain Membrane Key ATP synthase Matrix Stroma Higher [H+] Lower [H+] ADP + P i ATP H+

LE 10-17 STROMA (Low H+ concentration) Cytochrome complex H2O CO2 Light NADP+ ADP LIGHT REACTIONS CALVIN CYCLE ATP NADPH STROMA (Low H+ concentration) O2 [CH2O] (sugar) Cytochrome complex Photosystem II Photosystem I Light NADP+ reductase Light 2 H+ Fd NADP+ + 2H+ NADPH + H+ Pq Pc H2O THYLAKOID SPACE (High H+ concentration) 1/2 O2 +2 H+ 2 H+ To Calvin cycle Thylakoid membrane ATP synthase STROMA (Low H+ concentration) ADP + ATP P i H+

Phase 1: Carbon fixation Ribulose bisphosphate LE 10-18_1 H2O CO2 Input Light 3 (Entering one at a time) NADP+ ADP CO2 LIGHT REACTIONS CALVIN CYCLE ATP Phase 1: Carbon fixation NADPH Rubisco O2 [CH2O] (sugar) 3 P P Short-lived intermediate 3 P P 6 P Ribulose bisphosphate (RuBP) 3-Phosphoglycerate 6 ATP 6 ADP CALVIN CYCLE

LE 10-18_2 Input 3 (Entering one at a time) CO2 H2O CO2 Input Light 3 (Entering one at a time) NADP+ ADP CO2 LIGHT REACTIONS CALVIN CYCLE ATP Phase 1: Carbon fixation NADPH Rubisco O2 [CH2O] (sugar) 3 P P Short-lived intermediate 3 P P 6 P Ribulose bisphosphate (RuBP) 3-Phosphoglycerate 6 ATP 6 ADP CALVIN CYCLE 6 P P 1,3-Bisphosphoglycerate 6 NADPH 6 NADP+ 6 P i 6 P Glyceraldehyde-3-phosphate (G3P) Phase 2: Reduction 1 P G3P (a sugar) Glucose and other organic compounds Output

LE 10-18_3 Input 3 (Entering one at a time) CO2 H2O CO2 Input Light 3 (Entering one at a time) NADP+ ADP CO2 LIGHT REACTIONS CALVIN CYCLE ATP Phase 1: Carbon fixation NADPH Rubisco O2 [CH2O] (sugar) 3 P P Short-lived intermediate 3 P P 6 P Ribulose bisphosphate (RuBP) 3-Phosphoglycerate 6 ATP 6 ADP 3 ADP CALVIN CYCLE 3 6 P P ATP 1,3-Bisphosphoglycerate 6 NADPH Phase 3: Regeneration of the CO2 acceptor (RuBP) 6 NADP+ 6 P i 5 P G3P 6 P Glyceraldehyde-3-phosphate (G3P) Phase 2: Reduction 1 P G3P (a sugar) Glucose and other organic compounds Output

LE 10-19 Mesophyll cell Mesophyll cell CO2 Photosynthetic cells of C4 plant leaf PEP carboxylase Bundle- sheath cell The C4 pathway Oxaloacetate (4 C) PEP (3 C) Vein (vascular tissue) ADP Malate (4 C) ATP C4 leaf anatomy Pyruvate (3 C) Bundle- sheath cell Stoma CO2 CALVIN CYCLE Sugar Vascular tissue

LE 10-20 Sugarcane Pineapple C4 CAM CO2 CO2 Mesophyll cell CO2 incorporated into four-carbon organic acids (carbon fixation) Night Organic acid Organic acid Bundle- sheath cell CO2 CO2 Day Organic acids release CO2 to Calvin cycle CALVIN CYCLE CALVIN CYCLE Sugar Sugar Spatial separation of steps Temporal separation of steps

Photosystem II Electron transport chain Photosystem I Light reactions Calvin cycle H2O CO2 Light NADP+ ADP + P i RuBP 3-Phosphoglycerate Photosystem II Electron transport chain Photosystem I ATP G3P Starch (storage) NADPH Amino acids Fatty acids Chloroplast O2 Sucrose (export)

LE 10-UN200 pH 7 pH 4 pH 4 pH 8 ATP