Fig. 10-9

Wavelength of light (nm)

(b) Action spectrum

(a) Absorption spectra

(c) Engelmann’s experiment

Aerobic bacteria

RESULTS

Ra

te o

f p

ho

tos

yn

the

sis

(me

as

ure

d b

y O

2 re

lea

se

)A

bs

orp

tio

n o

f li

gh

t b

yc

hlo

rop

las

t p

igm

en

ts

Filamentof alga

Chloro- phyll a Chlorophyll b

Carotenoids

500400 600 700

700600500400

Fig. 10-10

Porphyrin ring:light-absorbing“head” of molecule;note magnesiumatom at center

in chlorophyll aCH3

Hydrocarbon tail:interacts with hydrophobicregions of proteins insidethylakoid membranes ofchloroplasts; H atoms notshown

CHO in chlorophyll b

Fig. 10-17

Fig. 10-17

Light

Fd

Cytochromecomplex

ADP +

i H+

ATPP

ATPsynthase

ToCalvinCycle

STROMA(low H+ concentration)

Thylakoidmembrane

THYLAKOID SPACE(high H+ concentration)

STROMA(low H+ concentration)

Photosystem II Photosystem I

4 H+

4 H+

Pq

Pc

LightNADP+

reductase

NADP+ + H+

NADPH

+2 H+

H2OO2

e–

e–

1/21

2

3

Fig. 10-19

Fig. 10-19

C4 leaf anatomy

Mesophyll cellPhotosyntheticcells of C4

plant leafBundle-sheathcell

Vein(vascular tissue)

Stoma

The C4 pathway

Mesophyllcell CO2PEP carboxylase

Oxaloacetate (4C)

Malate (4C)

PEP (3C)ADP

ATP

Pyruvate (3C)

CO2

Bundle-sheathcell

CalvinCycle

Sugar

Vasculartissue

Fig. 10-19Fig. 10-19

Fig. 10-19a

Stoma

C4 leaf anatomy

Photosyntheticcells of C4

plant leaf

Vein(vascular tissue)

Bundle-sheathcell

Mesophyll cell

Fig. 10-19b

Fig. 10-19b

Sugar

CO2

Bundle-sheathcell

ATP

ADP

Oxaloacetate (4C) PEP (3C)

PEP carboxylase

Malate (4C)

Mesophyllcell

CO2

CalvinCycle

Pyruvate (3C)

Vasculartissue

The C4

pathway

Fig. 10-20

CO2

Sugarcane

Mesophyllcell

CO2

C4

Bundle-sheathcell

Organic acidsrelease CO2 to Calvin cycle

CO2 incorporatedinto four-carbonorganic acids(carbon fixation)

Pineapple

Night

Day

CAM

SugarSugar

CalvinCycle

CalvinCycle

Organic acid Organic acid

(a) Spatial separation of steps (b) Temporal separation of steps

CO2 CO2

1

2