reece • urry • cain • wasserman • minorsky • jackson 11
TRANSCRIPT
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CAMPBELL
BIOLOGY
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TENTHEDITION
CAMPBELL
BIOLOGYReece • Urry • Cain • Wasserman •Minorsky • Jackson
TENTHEDITION
11Photosynthetic Processes
Lecture Presentation by Nicole Tunbridge andKathleen Fitzpatrick
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The Process That Feeds the Biosphere
Photosynthesis is the process that converts solar energy into chemical energy
Directly or indirectly, photosynthesis nourishes almost the entire living world
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Autotrophs sustain themselves without eating anything derived from other organisms
Autotrophs are the producers of the biosphere, producing organic molecules from CO2 and other inorganic molecules
Almost all plants are photoautotrophs, using the energy of sunlight to make organic molecules
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Figure 11.1
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Figure 11.1a
Other organisms also benefit fromphotosynthesis.
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Photosynthesis occurs in plants, algae, certain other unicellular eukaryotes, and some prokaryotes
These organisms feed not only themselves but also most of the living world
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Figure 11.2
(a) Plants
(b) Multicellular alga
(c) Unicellular eukaryotes
(d) Cyanobacteria
(e) Purple sulfurbacteria
40μm
1 μm
11 μ
m
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Figure 11.2a
(a) Plants
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Figure 11.2b
(b) Multicellular alga
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Figure 11.2c
(c) Unicellular eukaryotes11 μ
m
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Figure 11.2d
(d) Cyanobacteria 40μm
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Figure 11.2e
1 μm
(e) Purple sulfurbacteria
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Heterotrophs obtain their organic material from other organisms
Heterotrophs are the consumers of the biosphere
Almost all heterotrophs, including humans, depend on photoautotrophs for food and O2
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Earth’s supply of fossil fuels was formed from the remains of organisms that died hundreds of millions of years ago
In a sense, fossil fuels represent stores of solar energy from the distant past
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Figure 11.3
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Concept 11.1: Photosynthesis converts light energy to the chemical energy of food Chloroplasts are structurally similar to and likely
evolved from photosynthetic bacteria
The structural organization of these organelles allows for the chemical reactions of photosynthesis
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Chloroplasts: The Sites of Photosynthesis in Plants Leaves are the major locations of photosynthesis
Chloroplasts are found mainly in cells of the mesophyll, the interior tissue of the leaf
Each mesophyll cell contains 30–40 chloroplasts
CO2 enters and O2 exits the leaf through microscopic pores called stomata
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A chloroplast has an envelope of two membranes surrounding a dense fluid called the stroma
Thylakoids are connected sacs in the chloroplast which compose a third membrane system
Thylakoids may be stacked in columns called grana
Chlorophyll, the pigment which gives leaves their green colour, resides in the thylakoid membranes
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Figure 11.4
Stroma Granum
ThylakoidThylakoidspace
Outermembrane
IntermembranespaceInnermembrane
20 μm
Stomata
Chloroplast Mesophyllcell
1 μm
Mesophyll
Chloroplasts VeinLeaf cross section
CO2 O2
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Figure 11.4aLeaf cross section
Stomata
Chloroplast
Mesophyll
Chloroplasts Vein
Mesophyllcell
20 μm
CO2 O2
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Figure 11.4b
Chloroplast
Stroma Granum
ThylakoidThylakoidspace
Outermembrane
IntermembranespaceInnermembrane
1 μm
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Figure 11.4c
Stroma Granum
1 μm
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Figure 11.4d
20 μm
Mesophyllcell
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Tracking Atoms Through Photosynthesis: Scientific Inquiry Photosynthesis is a complex series of reactions
that can be summarized as the following equation:
6 CO2 12 H2O Light energy → C6H12O6 6 O2 6 H2O
The overall chemical change during photosynthesis is the reverse of the one that occurs during cellular respiration
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The Splitting of Water
Chloroplasts split H2O into hydrogen and oxygen, incorporating the electrons of hydrogen into sugar molecules and releasing oxygen as a by-product
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Figure 11.5
Reactants:
Products:
6 CO2 12 H2O
C6H12O6 6 H2O 6 O2
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Photosynthesis as a Redox Process
Photosynthesis reverses the direction of electron flow compared to respiration
Photosynthesis is a redox process in which H2O is oxidized and CO2 is reduced
Photosynthesis is an endergonic process; the energy boost is provided by light
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Figure 11.UN01
becomes reduced
becomes oxidized
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The Two Stages of Photosynthesis: A Preview
Photosynthesis consists of the light reactions(the photo part) and Calvin cycle (the synthesispart)
The light reactions (in the thylakoids)
Split H2O
Release O2
Reduce the electron acceptor NADP to NADPH
Generate ATP from ADP by photophosphorylation
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The Calvin cycle (in the stroma) forms sugar from CO2, using ATP and NADPH
The Calvin cycle begins with carbon fixation, incorporating CO2 into organic molecules
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Figure 11.6-1
Light
Thylakoid Stroma
Chloroplast
LIGHTREACTIONS
NADP+
ADP
P i
H2O
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Figure 11.6-2
Light
Thylakoid Stroma
Chloroplast
LIGHTREACTIONS
NADP+
ADP
P i
H2O
NADPH
ATP
O2
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Figure 11.6-3
Light
Thylakoid Stroma
Chloroplast
LIGHTREACTIONS
NADP+
ADP
P i
H2O
O2
CO2
NADPH
ATP
CALVINCYCLE
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Figure 11.6-4
Light
Thylakoid Stroma
Chloroplast
LIGHTREACTIONS
NADP+
ADP
P i
H2O
[CH2O](sugar)
CALVINCYCLE
CO2
NADPH
ATP
O2
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BioFlix: The Carbon Cycle
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BioFlix: Photosynthesis
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Concept 11.2: The light reactions convert solar energy to the chemical energy of ATP and NADPH Chloroplasts are solar-powered chemical factories
Their thylakoids transform light energy into the chemical energy of ATP and NADPH
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The Nature of Sunlight
Light is a form of electromagnetic energy, also called electromagnetic radiation
Like other electromagnetic energy, light travels in rhythmic waves
Wavelength is the distance between crestsof waves
Wavelength determines the type of electromagnetic energy
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The electromagnetic spectrum is the entire range of electromagnetic energy, or radiation
Visible light consists of wavelengths (including those that drive photosynthesis) that produce colors we can see
Light also behaves as though it consists of discrete particles, called photons
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Figure 11.7
Visible light
Gammarays X-rays UV Infrared Micro-
wavesRadiowaves
380 450 500 550 600 650 700 750 nmShorter wavelength
Higher energy Lower energyLonger wavelength
11−5 11−3nm nm 1 nm 3 nm11 6 nm11 9(11 nm)1 m
113 m
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Photosynthetic Pigments: The Light Receptors
Pigments are substances that absorb visible light
Different pigments absorb different wavelengths
Wavelengths that are not absorbed are reflected or transmitted
Leaves appear green because chlorophyll reflects and transmits green light
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Figure 11.8
Light
Chloroplast
Reflectedlight
Granum
Transmittedlight
Absorbedlight
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Animation: Light and Pigments
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A spectrophotometer measures a pigment’s ability to absorb various wavelengths
This machine sends light through pigments and measures the fraction of light transmitted at each wavelength
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Figure 11.9
Whitelight
Refractingprism
Chlorophyllsolution
Photoelectrictube
Galvanometer
The high transmittance (lowabsorption) reading indicates thatchlorophyll absorbs verylittle green light.
Slit moves to pass lightof selected wavelength.
Greenlight
Bluelight
The low transmittance (highabsorption) reading indicatesthat chlorophyll absorbsmost blue light.
12 3
4
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An absorption spectrum is a graph plotting a pigment’s light absorption versus wavelength
The absorption spectrum of chlorophyll asuggests that violet-blue and red light work best for photosynthesis
An action spectrum profiles the relative effectiveness of different wavelengths of radiation in driving a process
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Figure 11.10Chloro-phyll a Chlorophyll b
Carotenoids
400 500 600 700Wavelength of light (nm)
(a) Absorption spectraA
bsor
ptio
nof
ligh
t by
chlo
ropl
ast
pigm
ents
Rat
e of
phot
osyn
thes
is(m
easu
red
by O
2re
leas
e)
400 500 600 700
400 500 600 700
(b) Action spectrum
(c) Engelmann’s experiment
Aerobic bacteriaFilament of alga
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Figure 11.10a
Chloro-phyll a Chlorophyll b
Carotenoids
400 500 600 700Wavelength of light (nm)
(a) Absorption spectra
Abs
orpt
ion
of li
ght b
ych
loro
plas
tpi
gmen
ts
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Figure 11.10b
Rat
e of
phot
osyn
thes
is(m
easu
red
by O
2re
leas
e)
400 500 600 700(b) Action spectrum
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Figure 11.10c
400 500 600 700(c) Engelmann’s experiment
Aerobic bacteriaFilament of alga
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The action spectrum of photosynthesis was first demonstrated in 1883 by Theodor W. Engelmann
In his experiment, he exposed different segments of a filamentous alga to different wavelengths
Areas receiving wavelengths favorable to photosynthesis produced excess O2
He used the growth of aerobic bacteria clustered along the alga as a measure of O2 production
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Chlorophyll a is the main photosynthetic pigment
Accessory pigments, such as chlorophyll b, broaden the spectrum used for photosynthesis
The difference in the absorption spectrum between chlorophyll a and b is due to a slight structural difference between the pigment molecules
Accessory pigments called carotenoids absorb excessive light that would damage chlorophyll
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Figure 11.11
Porphyrin ring:light-absorbing“head” of molecule;note magnesiumatom at center
Hydrocarbon tail:interacts with hydrophobicregions of proteins insidethylakoid membranes ofchloroplasts; H atoms notshown
CH in chlorophyll ain chlorophyll b
3CHOCH3
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Video: Space-Filling Model of Chlorophyll a
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Accessory pigments called carotenoids function in photoprotection; they absorb excessive light that would damage chlorophyll
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Excitation of Chlorophyll by Light
When a pigment absorbs light, it goes from a ground state to an excited state, which is unstable
When excited electrons fall back to the ground state, photons are given off, an afterglow called fluorescence
If illuminated, an isolated solution of chlorophyll will fluoresce, giving off light and heat
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Figure 11.12
Excitedstate
Heat
(a) Excitation of isolated chlorophyll molecule (b) Fluorescence
Groundstate
Photon(fluorescence)
PhotonChlorophyll
molecule
Ener
gy o
f ele
ctro
n
e−
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Figure 11.12a
(b) Fluorescence
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A Photosystem: A Reaction-Center Complex Associated with Light-Harvesting Complexes A photosystem consists of a reaction-center
complex (a type of protein complex) surrounded by light-harvesting complexes
The light-harvesting complexes (pigment molecules bound to proteins) transfer the energy of photons to the reaction center
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Figure 11.13
(a) How a photosystem harvests light (b) Structure of a photosystem
Chlorophyll STROMA
THYLA-KOIDSPACE
Proteinsubunits
Thyl
akoi
d m
embr
ane
Pigmentmolecules
Primaryelectronacceptor
Reaction-centercomplex
STROMA
Photosystem
Light-harvestingcomplexes
Photon
Transferof energy
Special pair of chloro-phyll a molecules
THYLAKOID SPACE(INTERIOR OF THYLAKOID)
Thyl
akoi
d m
embr
ane
e−
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Figure 11.13a
(a) How a photosystem harvests light
Pigmentmolecules
Primaryelectronacceptor
Reaction-centercomplex
STROMA
Photosystem
Light-harvestingcomplexes
Photon
Transferof energy
Special pair of chloro-phyll a molecules
THYLAKOID SPACE(INTERIOR OF THYLAKOID)
Thyl
akoi
d m
embr
ane
e−
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Figure 11.13b
(b) Structure of a photosystem
Chlorophyll STROMA
THYLA-KOIDSPACE
Proteinsubunits
Thyl
akoi
d m
embr
ane
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A primary electron acceptor in the reaction center accepts excited electrons and is reduced as a result
Solar-powered transfer of an electron from a chlorophyll a molecule to the primary electron acceptor is the first step of the light reactions
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There are two types of photosystems in the thylakoid membrane
Photosystem II (PS II) functions first (the numbers reflect order of discovery) and is best at absorbing a wavelength of 680 nm
The reaction-center chlorophyll a of PS II is called P680
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Photosystem I (PS I) is best at absorbing a wavelength of 700 nm
The reaction-center chlorophyll a of PS I is called P700
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Linear Electron Flow
During the light reactions, there are two possible routes for electron flow: cyclic and linear
Linear electron flow, the primary pathway, involves both photosystems and produces ATP and NADPH using light energy
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There are 8 steps in linear electron flow:
1. A photon hits a pigment and its energy is passed among pigment molecules until it excites P680
2. An excited electron from P680 is transferred to the primary electron acceptor (we now call it P680)
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Figure 11.UN02
Light
H2O CO2
O2
LIGHTREACTIONS
CALVINCYCLE
ATP
NADPH
ADPNADP
[CH2O] (sugar)
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Figure 11.14-1
Pigmentmolecules
e−
1
2
P680Light
Photosystem II(PS II)
Primaryacceptor
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Figure 11.14-2
Pigmentmolecules
e−
1
2
P680Light
Photosystem II(PS II)
Primaryacceptor
3e−e−
2 H
O2
H2O
½
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Figure 11.14-3
Pigmentmolecules
e−
1
2
P680Light
Photosystem II(PS II)
Primaryacceptor
3e−e−
2 H
O2
H2O
ATP
4
5
Electrontransportchain
Cytochromecomplex
Pq
Pc½
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Figure 11.14-4
Pigmentmolecules
e−
1
2
P680Light
Photosystem II(PS II)
Primaryacceptor
3e−e−
2 H
O2
H2O
ATP
4
5
Electrontransportchain
Cytochromecomplex
Pq
PcP700
Light
Photosystem I(PS I)
6
Primaryacceptor
e−
½
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Figure 11.14-5
Pigmentmolecules
e−
1
2
P680Light
Photosystem II(PS II)
Primaryacceptor
3e−e−
2 H
O2
H2O
ATP
4
5
Electrontransportchain
Cytochromecomplex
Pq
PcP700
Light
Photosystem I(PS I)
6
Primaryacceptor
e−e−
7
8Fd
e−
Electrontransportchain
NADP
reductaseNADPH
NADP
H
½
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3. H2O is split by enzymes, and the electrons are transferred from the hydrogen atoms to P680, thus reducing it to P680
P680 is the strongest known biological oxidizing agent
O2 is released as a by-product of this reaction
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4. Each electron “falls” down an electron transport chain from the primary electron acceptor of PS II to PS I
5. Energy released by the fall drives the creation of a proton gradient across the thylakoid membrane
Diffusion of H (protons) across the membrane drives ATP synthesis
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6. In PS I (like PS II), transferred light energy excites P700, which loses an electron to an electron acceptor
P700 (P700 that is missing an electron) accepts an electron passed down from PS II via the electron transport chain
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7. Each electron “falls” down an electron transport chain from the primary electron acceptor of PS I to the protein ferredoxin (Fd)
8. The electrons are then transferred to NADP and reduce it to NADPH
The electrons of NADPH are available for the reactions of the Calvin cycle
This process also removes an H from the stroma
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The energy changes of electrons during linear flow through the light reactions can be shown in a mechanical analogy
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Figure 11.15
Millmakes
ATP NADPH
Photosystem II Photosystem I
ATP
e−
e−
e−
e−
e−
e−
e−
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Cyclic Electron Flow
In cyclic electron flow, electrons cycle back from Fd to the PS I reaction center
Cyclic electron flow uses only photosystem I and produces ATP, but not NADPH
No oxygen is released
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Figure 11.16
Primaryacceptor
Primaryacceptor
Fd
Cytochromecomplex
Pc
Pq
Photosystem IIPhotosystem I
FdNADP
HNADP
reductaseNADPH
ATP
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Some organisms such as purple sulfur bacteria have PS I but not PS II
Cyclic electron flow is thought to have evolved before linear electron flow
Cyclic electron flow may protect cells from light-induced damage
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A Comparison of Chemiosmosis in Chloroplasts and Mitochondria Chloroplasts and mitochondria generate ATP by
chemiosmosis, but use different sources of energy
Mitochondria transfer chemical energy from food to ATP; chloroplasts transform light energy into the chemical energy of ATP
Spatial organization of chemiosmosis differs between chloroplasts and mitochondria but also shows similarities
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In mitochondria, protons are pumped to the intermembrane space and drive ATP synthesis as they diffuse back into the mitochondrial matrix
In chloroplasts, protons are pumped into the thylakoid space and drive ATP synthesis as they diffuse back into the stroma
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Figure 11.17
MITOCHONDRIONSTRUCTURE
CHLOROPLASTSTRUCTURE
Thylakoidmembrane
Stroma
ATP
Thylakoidspace
Inter-membrane
space
Innermembrane
MatrixKey
Diffusion
Electrontransport
chain
ATPsynthase
ADP H
H
Higher [H]Lower [H]
P i
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ATP and NADPH are produced on the side facing the stroma, where the Calvin cycle takes place
In summary, light reactions generate ATP and increase the potential energy of electrons by moving them from H2O to NADPH
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Figure 11.18
Photosystem II Photosystem ICytochromecomplex
Light
Pq
Light 4 H
2 H 4 HO2
H2OPc
Fd3
21
NADP
ToCalvinCycle
NADP
reductase
STROMA(low H concentration)
ATPsynthase
THYLAKOID SPACE(high H concentration)
Thylakoidmembrane
ADP
H ATPP i
e e
NADPH
½
H
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Figure 11.18a
STROMA(low H concentration)
ATPADP
ATPsynthase
P i
H
THYLAKOID SPACE(high H concentration)
4 H
Cytochromecomplex
LightPhotosystem I
Pc
Pq
4 H
Light
Photosystem II4 H
Pc
Fd
Thylakoidmembrane
2 H
H2OO2½
ee 21
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Figure 11.18b
Cytochromecomplex
LightPhotosystem I
Pc
Pq
Fd
NADP
reductase
NADP H
NADPH
ToCalvinCycle
STROMA(low H concentration)
ATPADP
ATPsynthase
P i
H
THYLAKOID SPACE(high H concentration)4 H
2
3
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Concept 11.3: The Calvin cycle uses the chemical energy of ATP and NADPH to reduce CO2 to sugar The Calvin cycle, like the citric acid cycle,
regenerates its starting material after molecules enter and leave the cycle
The cycle builds sugar from smaller molecules by using ATP and the reducing power of electrons carried by NADPH
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Carbon enters the cycle as CO2 and leaves as a sugar named glyceraldehyde 3-phospate (G3P)
For net synthesis of 1 G3P, the cycle must take place three times, fixing 3 molecules of CO2
The Calvin cycle has three phases1. Carbon fixation (catalyzed by rubisco)2. Reduction3. Regeneration of the CO2 acceptor (RuBP)
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Figure 11.UN03
Light
H2O CO2
O2
LIGHTREACTIONS
CALVINCYCLE
ATP
NADPH
ADPNADP
[CH2O] (sugar)
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Figure 11.19-1Input 3 CO2, entering one per cycle
Phase 1: Carbon fixationRubisco
3-Phosphoglycerate
CalvinCycle
RuBPPP3
P3 P
P6
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Figure 11.19-2Input 3 CO2, entering one per cycle
Phase 1: Carbon fixationRubisco
3-Phosphoglycerate
1,3-Bisphosphoglycerate
Phase 2:Reduction
G3P
CalvinCycle
RuBPPP3
P3 P
P6
6
6 ADP
P6 P
ATP
P6
6
6 NADP
6 P i
G3PP1
Output
Glucose andother organiccompounds
NADPH
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Figure 11.19-3Input 3 CO2, entering one per cycle
Phase 1: Carbon fixationRubisco
3-Phosphoglycerate
1,3-Bisphosphoglycerate
Phase 2:Reduction
G3P
CalvinCycle
G3P
Phase 3:Regenerationof RuBP
ATP
3 ADP
3
5 P
RuBPPP3
P3 P
P6
6
6 ADP
P6 P
ATP
P6
6
6 NADP
6 P i
G3PP1
Output
Glucose andother organiccompounds
NADPH
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Concept 11.4: Alternative mechanisms of carbon fixation have evolved in hot, arid climates Dehydration is a problem for plants, sometimes
requiring trade-offs with other metabolic processes, especially photosynthesis
On hot, dry days, plants close stomata, which conserves H2O but also limits photosynthesis
The closing of stomata reduces access to CO2 and causes O2 to build up
These conditions favor an apparently wasteful process called photorespiration
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Photorespiration: An Evolutionary Relic?
In most plants (C3 plants), initial fixation of CO2, via rubisco, forms a three-carbon compound(3-phosphoglycerate)
In photorespiration, rubisco adds O2 instead of CO2 in the Calvin cycle, producing a two-carbon compound
Photorespiration consumes O2 and organic fuel and releases CO2 without producing ATP or sugar
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Photorespiration may be an evolutionary relic because rubisco first evolved at a time when the atmosphere had far less O2 and more CO2
Photorespiration limits damaging products of light reactions that build up in the absence of the Calvin cycle
In many plants, photorespiration is a problem because on a hot, dry day it can drain as much as 50% of the carbon fixed by the Calvin cycle
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C4 Plants
C4 plants minimize the cost of photorespiration by incorporating CO2 into four-carbon compounds
There are two distinct types of cells in the leaves of C4 plants:
Bundle-sheath cells are arranged in tightly packed sheaths around the veins of the leaf
Mesophyll cells are loosely packed between the bundle sheath and the leaf surface
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Sugar production in C4 plants occurs in a three-step process:
1. The production of the four carbon precursors is catalyzed by the enzyme PEP carboxylase in the mesophyll cells
PEP carboxylase has a higher affinity for CO2than rubisco does; it can fix CO2 even when CO2concentrations are low
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2. These four-carbon compounds are exported to bundle-sheath cells
3. Within the bundle-sheath cells, they release CO2that is then used in the Calvin cycle
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Figure 11.20
Mesophyllcell
Bundle-sheathcell
Photo-syntheticcells ofC4 plantleaf
Vein(vasculartissue)
C4 leaf anatomy
Stoma
The C4 pathway
Mesophyllcell PEP carboxylase
Oxaloacetate (4C)
Malate (4C)
Pyruvate(3C)
CO2
ADPPEP (3C)
ATP
CO2
CalvinCycle
Bundle-sheathcell
Sugar
Vasculartissue
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Figure 11.20a
Mesophyllcell
Bundle-sheathcell
Photo-syntheticcells ofC4 plantleaf
Vein(vasculartissue)
C4 leaf anatomy
Stoma
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Figure 11.20bThe C4 pathway
Mesophyllcell PEP carboxylase
Oxaloacetate (4C)
Malate (4C)
Pyruvate(3C)
CO2
ADPPEP (3C)
ATP
CO2
CalvinCycle
Bundle-sheathcell
Sugar
Vasculartissue
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Since the Industrial Revolution in the 1800s, CO2 levels have risen greatly
Increasing levels of CO2 may affect C3 and C4plants differently, perhaps changing the relative abundance of these species
The effects of such changes are unpredictable and a cause for concern
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CAM Plants
Some plants, including succulents, use crassulacean acid metabolism (CAM) tofix carbon
CAM plants open their stomata at night, incorporating CO2 into organic acids
Stomata close during the day, and CO2 is released from organic acids and used in the Calvin cycle
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Figure 11.21
Sugarcane Pineapple
C4 CO2 CO2 CAM
Organicacid
Organicacid
Night
Day
CO2CO2
CalvinCycle
CalvinCycle
SugarSugar
Bundle-sheathcell
(a) Spatial separationof steps
(b) Temporal separationof steps
Mesophyllcell
2
1 1
2
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Figure 11.21a
Sugarcane
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Figure 11.21b
Pineapple
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The Importance of Photosynthesis: A Review
The energy entering chloroplasts as sunlight gets stored as chemical energy in organic compounds
Sugar made in the chloroplasts supplies chemical energy and carbon skeletons to synthesize the organic molecules of cells
Plants store excess sugar as starch in structures such as roots, tubers, seeds, and fruits
In addition to food production, photosynthesis produces the O2 in our atmosphere
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Figure 11.22a
O2 CO2
H2O
Sucrose(export)
H2O
Light
LIGHTREACTIONS:
Photosystem IIElectron transport
chainPhotosystem I
Electron transportchain
Chloroplast
NADP
ADPP i
NADPH
ATP
RuBP
G3P
CALVINCYCLE
Starch(storage)
3-Phosphoglycerate
Sucrose (export)O2H2O
Mesophyll cell
CO2
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Figure 11.22b
LIGHT REACTIONS CALVIN CYCLE REACTIONS
• Are carried out by moleculesin the thylakoid membranes
• Convert light energy to thechemical energy of ATPand NADPH
• Split H2O and release O2to the atmosphere
• Take place in the stroma• Use ATP and NADPH to convert
CO2 to the sugar G3P• Return ADP, inorganic phosphate,
and NADP to the light reactions
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Figure 11.23
Flow of Genetic Informationin the Cell:DNA → RNA → Protein(Chapters 5–7)
Movement AcrossCell Membranes(Chapter 7)
Energy Transformations in the Cell:Photosynthesis and CellularRespiration (Chapters 8–11)
DNA
mRNANucleus
Nuclearpore
Protein
Ribosome mRNA
Proteinin vesicle
Rough endoplasmicreticulum (ER)
VesicleformingGolgi
apparatus Protein
Plasmamembrane
Cell wall
Photosynthesisin chloroplast
Organicmolecules
Transportpump
Cellular respirationin mitochondrion
ATP
ATP
ATP
ATP
CO2
H2O
H2OCO2
O2
O25
4
3
2
1
7
8
Vacuole
911
11
6
MAKE CONNECTIONSThe Working Cell
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Figure 11.23a
Flow of Genetic Information in the Cell:DNA → RNA → Protein (Chapters 5–7)
DNA
mRNANucleus
mRNA
Nuclearpore
ProteinProteinin vesicle
Rough endoplasmicreticulum (ER)
Ribosome
1
2
3
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Figure 11.23b
Plasmamembrane
4
Golgiapparatus
Vesicleforming
Protein
Cell wall
Flow of Genetic Information in the Cell:DNA → RNA → Protein (Chapters 5–7)
5
6
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Figure 11.23c
Photosynthesisin chloroplast
Organicmolecules
Cellular respirationin mitochondrion
Transportpump
Movement AcrossCell Membranes (Chapter 7)
Energy Transformations inthe Cell: Photosynthesis andCellular Respiration(Chapters 8–11)
O2
O2
H2OCO2
CO2
H2OATP
ATP
ATP
ATP
7
8
11
119
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Figure 11.UN04a
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Figure 11.UN04b
Corn plant surroundedby invasive velvetleafplants
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Figure 11.UN05
Primaryacceptor
Primaryacceptor
Pq
Cytochromecomplex
Photosystem IIPhotosystem I
Pc
Fd
NADPH
NADP
HNADP
reductase
H2O
O2
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Figure 11.UN06
Regeneration ofCO2 acceptor
CalvinCycle
Carbon fixation
Reduction
1 G3P (3C)
5 x 3C
3 x 5C 6 x 3C
3 CO2
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Figure 11.UN07
pH 7
pH 4
pH 4
pH 8
ATP
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Figure 11.UN08