Photosynthesis. 1. An Overview of Photosynthesis & Respiration 2. Autotrophs and producers 3. Electromagnetic Spectrum & light energy 4. Chloroplasts:

Photosynthesis

1. An Overview of Photosynthesis & Respiration

2. Autotrophs and producers

3. Electromagnetic Spectrum & light energy

4. Chloroplasts: Structure and Function

5. Photosynthetic pigments

6. Chemical Reactions of Photosynthesis

Outline - Photosynthesis

Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings

CO2

H2O

Glucose

O2

ATP

Sunlight

Photosynthesis

Cellular respiration

Heat

–Respiration & Photosynthesis are Related

Energy to Drive Metabolism

HETEROTROPHS ConsumersAUTOTROPHS Producers

Harvest sunlight Convert solar energy into chemical energyExamples of autotrophs

PlantsAlgaeCyanobacteria

Increasingenergy

Increasingwavelength

0.1 nm 1 nm 10 nm 1000 nm 0.1 cm 1 cm 1 m 100 m

Gamma raysUV

lightX

raysInfrared

Radio waves

400 nm 430 nm 500 nm 560 nm 600 nm 650 nm 740 nm

Visible light

Electromagnetic Spectrum

Light Absorption During Photosynthesis

White

Light

Sun

Carotenoidsorange/yellow

Chlorophyllsgreen

Pigments of Photosynthesis

Wavelength (nm)400 450 500 550 600 650 700

Am

ou

nt

of

lig

ht

abso

rpti

on

Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

Chlorophyll aChlorophyll b

Carotenoid

Absorption Spectrum of Photosynthetic PigmentsChlorophyll a, Chlorophyll b & Carotenoids

Photosynthesis Occurs in Chloroplasts


Photosynthesis is a redox process

CO2 is reduced

H2O is oxidized

Reduction

Oxidation

6 O26 CO2 6 H2O C6H12O6

Photosynthesis Equation

Fig. 10.6b (TEArt) Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

Chloroplast Structure

Thylakoid

Granum

Stroma


Location of PhotosynthesisCarbon Dioxide Used & Sugar Produced

Water Used & Oxygen Produced

CO2

H20

Stroma

Thylakoid

Reactions of Photosynthesis

Light Harvesting

Light-Dependent Reactions

O2

Carbohydrates

ADP NADPHATP NADP+

Light Independent

Reactions

Sugar Building

Calvin Cycle

Fig. 10.6a (TEArt)

Chlorophyll moleculesand Carotenoidsin light-harvestingprotein complex

Thylakoidmembrane


Photosynthesis: Light Harvesting by Photosystems

Reaction Center Chlorophyll

Sun

Fig. 10.10 (TEArt)

ElectronAcceptor

Photon

Chlorophyllmolecules

Photosystem

e-


Reactioncenter

chlorophyll


e-

Photosystem I Reduces NADP+

e-

Photosystem I

e-

PSII Reaction Center

Photosystem II Supplies Electrons to PSI

Photosystem IIWater Splitting & Oxygen Production

Photosystem II

e-


H2OO2

H+H+

e-

OO

NADPH

NADP

e-

e-


H+

H+ H+H+

H+H+

H+

Fig. 10.6b (TEArt) Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

Thylakoid Structure

Thylakoid

Fig. 10.16b (TEArt)

Photosystem II b6-f complex ATP synthase

H+Photon

Stroma

Thylakoidspace

Q

H2O

ATPADP

e-

H+

H+

H+H+H+

H+2H+12 02

_


Stroma

Chemiosomosis & ATP Synthesis in Chloroplasts

Fig. 10.14 (TEArt)

Water-splittingenzyme

Photon

Photon

Ferredoxin

Plastoquinone

Photosystem II

NADP+ + H+

b6-fcomplex

NADPreductase

b6-f complex

Photosystem I NADP reductase

H2O2H+ + O2

H+

pC

Q

P700

P680

NADPH

Fd

Reactioncenter

e–

Plastocyanin

12

Excitedreactioncenter

e– e–

e–

En

erg

y o

f el

ectr

on

s Reactioncenter

__



Figure 7.8B

e–

ATP

Photon

Photon

Photosystem II Photosystem I

NADPHe–

e– e–

e–

e–

e–

Light Reactions Mechanical Analogy

H2O provides electrons electron transport chainreduce NADPHATP synthesized

Oxygen released

H2O

O2 e-

Summary of Light Harvesting Reactions

1. H2O provides electrons for electron transport chains

2. NADP reduced to NADPH

3. ATP synthesized by chemiosmosis

4. Oxygen released

1. Fixation 2. Reduction 3. Regeneration

Sugar Building – The Calvin Cycle1 2 3

CO2P

Glucose

NADPH

ATP

Glyceraldehyde3-phosphate

RuBP 3-phosphoglycerate

Glyceraldehyde3-phosphate

RuBP


PHOTOSYNTHESIS REVIEW

Figure 7.11

Light H2O CO2

NADP+

Photosystem II

Photosystem I

Light Reactions

ADP

P+

RUBP

CALVINCYCLE

3-PGA

Stroma

G3PNADPH

ATP

O2Sugars


Cellulose

Starch

Other organiccompounds

Thylakoidmembranes

ChloroplastReactants

Products


CO2

H2O

Glucose

O2

ATP

Sunlight

Heat

Importance of Photosynthesis

Photosynthesis


END Photosynthesis

END Photosynthesis

Documents

Photosynthesis. 1. An Overview of Photosynthesis & Respiration 2. Autotrophs and producers 3. Electromagnetic Spectrum & light energy 4. Chloroplasts: