Energy Generation in
Mitochondria and Chloroplasts
Chapter 7
(1) Mitochondria,in all eukaryotic cells
The relationship between the structure and function of mit.
(2) Chloroplasts,in plant cells
The relationship between the structure and function of chl.
Mit,Oxidative phosphorylation → ATP
Chl,Photosynthesis → ATP + NADPH → Sugar
A,Mitochondrial structure and function
?The size and number of mitochondria reflect
the energy requirements of the cell.
1,Mitochondria and oxidative phosphorylation
Figure 7-4 Relationship between mitochondria and
microtubules.
Figure 7-3 Mitochondrial plasticity,Rapid changes of shape
are observed when a mitochondrion is visualized in a living cell,
Figure 7-5 Localization of mitochondria near sites of high
ATP utilization in cardiac muscle and a sperm tail.
?Inner and outer mitochondrial membranes enclose two
spaces,the matrix and intermembrane space.
Outer membrane:
Contains channel-forming protein,called Porin,
Permeable to all molecules of 5000 daltons or less.
Inner membrane (Impermeability):
Contains proteins with three types of functions:
(1) Electron-transport chain,Carry out oxidation reactions;
(2) ATP synthase,Makes ATP in the matrix;
(3) Transport proteins,Allow the passage of metabolites
Intermembrane space:
Contains several enzymes use ATP to phosphorylate
other nucleotides.
Matrix,Enzymes; Mit DNA,Ribosomes,etc.
Figure 14-6 Fractionation of purified
mitochondria into separate
components,These techniques have made
it possible to study the different proteins in each
mitochondrial compartment,The method shown,
which allows the processing of large numbers of
mitochondria at the same time,takes advantage
of the fact that in media of low osmotic strength
water flows into mitochondria and greatly
expands the matrix space (yellow),While the
cristae of the inner membrane allow it to unfold
to accommodate the expansion,the outer
membranewhich has no folds to begin
withbreaks,releasing a structure composed of
only the inner membrane and the matrix,
B,Specific functions localized within
the Mit by disruption of the organelle
and fractionation
Localization of metabolic functions within the mitochondrion
Outer membrane:
Phospholipid synthesis
fatty acid desaturation
Fatty acid elongation
Inner membrane:
Electron transport
Oxidative phosphorylation
Metabolite transport
Intermembrane space
Nucleotide phosphorylation
Matrix
Pyruvate oxidation
TCA cycle
? oxidation of fats
DNA replication,RNA transcription,
Protein translation
2,Molecular basis of oxidative
phosphorylation
A,Molecular basis of oxidation,Electron-
transport chain
B,Molecular basis of phosphorylation,
ATP synthase
? The structure of the ATP synthase
F1 particle is the catalytic subunit;
The F0 particle attaches to F1 and is
embedded in the inner membrane.
F1,5 subunits in
the ratio
3?:3?:1?:1?:1?
F0,1a,2b,12c
?F1 particles have ATP synthase activity
? Proton translocation through F0 drives ATP synthesis
by F1,Binding Change Model and rotational catalysis
Boyer proposed in
1979,and was
greatly stimulated
by the publication
in 1994 of the
structure for F1
complex (X-ray)
from bovine heart
mitochondria
?Direct experimental evidence supporting the
rotational catalysis.
Japan researcher,
Nature 386,300,
1997.
? The ATP synthase is a reversible coupling device
? Other roles for the proton-motive force in
addition to ATP synthase
C,Mithchell’s Chemiosmotic theory (1961)
?The pH and electrical gradient resulting from
transport of protons links oxidation to phosphorylation.
?When electrons are passed to carriers only able to
accept electrons,the H+ is translocated across the inner
membrane.
More than 2?1026 molecules (>160kg) of ATP per day in our bodies.
Electrons pass from NADH or FADH2 to O2,the terminal
electron acceptor,through a chain of carriers in the inner
membrane (FMN,Fe-S center,Heme group Fe,CoQ);
As electrons move through the electron-transport chain,H+ are
pumped out across the inner membrane,and form Proton
motive force;
Electrons move through the inner membrane via a series of
carriers of decreasing redox potential
If not all the detergent is removed,what will happen?
Figure 7-26 An experiment
demonstrating that the ATP
synthase is driven by proton
flow,By combining a light-
driven bacterial proton pump
(bacteriorhodopsin),an ATP
synthase purified from ox
heart mitochondria,and
phospholipids,vesicles were
produced that synthesized
ATP in response to light.
?Summary of the major activities during aerobic
respiration in a mitochondrion
NADH?O2,3ATP/2e;
FADH2?O2, 2ATP/2e
?生物氧化产生 ATP的统计
一个葡萄糖分子经过细胞呼吸全过程产生多少 ATP？
糖酵解：底物水平磷酸化产生 4 ATP（ 细胞质）
己糖分子活化消耗 2 ATP（ 细胞质）
产生 2NADH,经电子传递产生 4或 6 ATP
（ 线粒体）净积累 6或 8 ATP
丙酮酸氧化脱羧：产生 2NADH（ 线粒体），生成 6ATP
三羧酸循环：底物水平的磷酸化产生（线粒体） 2ATP；
产生 6NADH（ 线粒体），生成 18ATP；
产生 2FADH2（ 线粒体），生成 4 ATP
总计生成 36或 38 ATP
3,Chloroplast and photosynthesis
A,Comparison of a mitochondrion and a chloroplast.
Figure 14-39 The chloroplast,This photosynthetic organelle contains three
distinct membranes (the outer membrane,the inner membrane,and the thylakoid
membrane) that define three separate internal compartments (the intermembrane space,
the stroma,and the thylakoid space),The thylakoid membrane contains all of the
energy-generating systems of the chloroplast,In electron micrographs this membrane
appears to be broken up into separate units that enclose individual flattened vesicles
(see Figure 14-40),but these are probably joined into a single,highly folded membrane
in each chloroplast,As indicated,the individual thylakoids are interconnected,and they
tend to stack to form aggregates called grana,
(A) A wheat leaf cell in which a thin rim of cytoplasm containing chloroplasts surrounds
a large vacuole,(B) A thin section of a single chloroplast,showing the starch granules
and lipid droplets that have accumulated in the stroma as a result of the biosyntheses
occurring there,(C) A high-magnification view of a granum,showing its stacked thylakoid
membrane,(Courtesy of K,Plaskitt.)
Figure 7-42 Photosynthesis in a chloroplast,Water is oxidized
and oxygen is released in the photosynthetic electron-transfer reactions,while
carbon dioxide is assimilated (fixed) to produce carbohydrate in the carbon-
fixation reactions,
B,Photosynthesis
C,The antenna complex and photochemical reaction
center in a photosystem
Light-dependent reaction,Electron transport in the
thylakoid membrane and noncyclic
photophosphorylation,
Cyclic photophosphorylation:
Changes in redox potential during photosynthesis.
?Carbon dioxide fixation and the synthesis of
carbohydrate in C3 plants (Calvin cycle)
Figure 14-43 The initial reaction in carbon fixation,This reaction,in which
carbon dioxide is converted into organic carbon,is catalyzed in the chloroplast
stroma by the abundant enzyme ribulose bisphosphate carboxylase,The
product,3-phosphoglycerate,is also an important intermediate in glycolysis,the
two carbon atoms shaded in blue are used to produce phosphoglycolate when
the enzyme adds oxygen instead of CO2。
The structure and function in C4 plants
4,Organelle DNA and protein importing
A,Organelle DNA
?The size range of organelle DNA is similar to that of viral DNAs.
?Mit DNA,from <6,000bp (plasmodium falciparum) ～ >300,000bp (some land
plants),DNA of Mit genome (in mammals) ≈16,500bp(<0.001% of nuclear
genome) ; Chl genomes are about 10 times larger and contain about 120 genes.
?Chl DNA,from 70,000?to 200,000bp (genome of land plants);
?Genes in mtDNA encode rRNAs,tRNAs,and some
mitochondrial proteins
Human mt DNA,16,569bp
2 rRNAs,22 tRNAs,
13 polypeptides,NADH reductase,7 sub.
Cty b-c1 complex,1 cytb
Cyt oxidase,3 subunits
ATP synthase,2 F0 sub
Products of mt genes
are not exported
The organization of the liverwort(地钱 ) Chl genome
B,Mit and Chl have their own genetic systems
Mit and Chl are
organelles
semiautocephaly.
The synthesis of
mt proteins is
coordinated
C,The transport protein into Mit,And Chl,
?Tree proteins translocators in Mit membranes:
?TOM,TIM,and OXA complex
are multimeric membrane protein,
that catalyze protein transport
across Mit membrane,TOM,TIM
stand for translocase of the outer
and inner Mit membranes
respectively.
?TOM functions across the outer
membrane; TIM(TIM23 and
TIM22) function across the inner
membrane.
?OXA mediates the insertion of
inner membrane proteins that are
synthesized within the Mit,OXA
also helps TOM and TIM to insert
some proteins into the matrix.
?Translocation of precursors to the matrix occurs at
the sites where the outer and inner membranes are
close together;
?The protein import by Mit:
N-terminal signal sequence is recognized by receptors of TOM;
The protein is translocated across both Mit membranes at or near
special contact sites.
?Only unfolded proteins can be imported into Mit;
?Mit precursor proteins remain unfolded through interactions
with hsp70 chaperone proteins in the cytosol after they are
synthesized.
?ATP hydrolysis and H+ gradient are used to dtive
protein import into Mit
?Protein transport into the inner Mit membrane and
the intermembrane space requires two signal sequences
?Two signal
sequences are
required to
direct
proteins to
the Thylakoid
membrane in
Chl.
Translocation
into thylakoid
space or
thylakoid M can
occur by any
one of at least
four routes.
5,The proliferation and origin of Mit and Chl.
A,Organelle growth and division determine the
number of Mitochondria and Plastids in a cell
?Mit fission and fusion (a dividing Mit in a liver cell);
Dividing or Budding of Mit,
?Chloroplasts,dividing and formation of chloroplasts from
proplastids begins by the light-induced budding of the inner
membrane.
B,Origin,The endosymbiont theory
?Compare the ribosomal
RNA with the base sequence
of various bacterial rRNAs,
Purple bactria-Mitochondria
Cyanobacteria-Chloroplasts
Suggested evolutionary
pathway for the origin of
Mit.
Mitochondria and Chloroplasts
Chapter 7
(1) Mitochondria,in all eukaryotic cells
The relationship between the structure and function of mit.
(2) Chloroplasts,in plant cells
The relationship between the structure and function of chl.
Mit,Oxidative phosphorylation → ATP
Chl,Photosynthesis → ATP + NADPH → Sugar
A,Mitochondrial structure and function
?The size and number of mitochondria reflect
the energy requirements of the cell.
1,Mitochondria and oxidative phosphorylation
Figure 7-4 Relationship between mitochondria and
microtubules.
Figure 7-3 Mitochondrial plasticity,Rapid changes of shape
are observed when a mitochondrion is visualized in a living cell,
Figure 7-5 Localization of mitochondria near sites of high
ATP utilization in cardiac muscle and a sperm tail.
?Inner and outer mitochondrial membranes enclose two
spaces,the matrix and intermembrane space.
Outer membrane:
Contains channel-forming protein,called Porin,
Permeable to all molecules of 5000 daltons or less.
Inner membrane (Impermeability):
Contains proteins with three types of functions:
(1) Electron-transport chain,Carry out oxidation reactions;
(2) ATP synthase,Makes ATP in the matrix;
(3) Transport proteins,Allow the passage of metabolites
Intermembrane space:
Contains several enzymes use ATP to phosphorylate
other nucleotides.
Matrix,Enzymes; Mit DNA,Ribosomes,etc.
Figure 14-6 Fractionation of purified
mitochondria into separate
components,These techniques have made
it possible to study the different proteins in each
mitochondrial compartment,The method shown,
which allows the processing of large numbers of
mitochondria at the same time,takes advantage
of the fact that in media of low osmotic strength
water flows into mitochondria and greatly
expands the matrix space (yellow),While the
cristae of the inner membrane allow it to unfold
to accommodate the expansion,the outer
membranewhich has no folds to begin
withbreaks,releasing a structure composed of
only the inner membrane and the matrix,
B,Specific functions localized within
the Mit by disruption of the organelle
and fractionation
Localization of metabolic functions within the mitochondrion
Outer membrane:
Phospholipid synthesis
fatty acid desaturation
Fatty acid elongation
Inner membrane:
Electron transport
Oxidative phosphorylation
Metabolite transport
Intermembrane space
Nucleotide phosphorylation
Matrix
Pyruvate oxidation
TCA cycle
? oxidation of fats
DNA replication,RNA transcription,
Protein translation
2,Molecular basis of oxidative
phosphorylation
A,Molecular basis of oxidation,Electron-
transport chain
B,Molecular basis of phosphorylation,
ATP synthase
? The structure of the ATP synthase
F1 particle is the catalytic subunit;
The F0 particle attaches to F1 and is
embedded in the inner membrane.
F1,5 subunits in
the ratio
3?:3?:1?:1?:1?
F0,1a,2b,12c
?F1 particles have ATP synthase activity
? Proton translocation through F0 drives ATP synthesis
by F1,Binding Change Model and rotational catalysis
Boyer proposed in
1979,and was
greatly stimulated
by the publication
in 1994 of the
structure for F1
complex (X-ray)
from bovine heart
mitochondria
?Direct experimental evidence supporting the
rotational catalysis.
Japan researcher,
Nature 386,300,
1997.
? The ATP synthase is a reversible coupling device
? Other roles for the proton-motive force in
addition to ATP synthase
C,Mithchell’s Chemiosmotic theory (1961)
?The pH and electrical gradient resulting from
transport of protons links oxidation to phosphorylation.
?When electrons are passed to carriers only able to
accept electrons,the H+ is translocated across the inner
membrane.
More than 2?1026 molecules (>160kg) of ATP per day in our bodies.
Electrons pass from NADH or FADH2 to O2,the terminal
electron acceptor,through a chain of carriers in the inner
membrane (FMN,Fe-S center,Heme group Fe,CoQ);
As electrons move through the electron-transport chain,H+ are
pumped out across the inner membrane,and form Proton
motive force;
Electrons move through the inner membrane via a series of
carriers of decreasing redox potential
If not all the detergent is removed,what will happen?
Figure 7-26 An experiment
demonstrating that the ATP
synthase is driven by proton
flow,By combining a light-
driven bacterial proton pump
(bacteriorhodopsin),an ATP
synthase purified from ox
heart mitochondria,and
phospholipids,vesicles were
produced that synthesized
ATP in response to light.
?Summary of the major activities during aerobic
respiration in a mitochondrion
NADH?O2,3ATP/2e;
FADH2?O2, 2ATP/2e
?生物氧化产生 ATP的统计
一个葡萄糖分子经过细胞呼吸全过程产生多少 ATP？
糖酵解：底物水平磷酸化产生 4 ATP（ 细胞质）
己糖分子活化消耗 2 ATP（ 细胞质）
产生 2NADH,经电子传递产生 4或 6 ATP
（ 线粒体）净积累 6或 8 ATP
丙酮酸氧化脱羧：产生 2NADH（ 线粒体），生成 6ATP
三羧酸循环：底物水平的磷酸化产生（线粒体） 2ATP；
产生 6NADH（ 线粒体），生成 18ATP；
产生 2FADH2（ 线粒体），生成 4 ATP
总计生成 36或 38 ATP
3,Chloroplast and photosynthesis
A,Comparison of a mitochondrion and a chloroplast.
Figure 14-39 The chloroplast,This photosynthetic organelle contains three
distinct membranes (the outer membrane,the inner membrane,and the thylakoid
membrane) that define three separate internal compartments (the intermembrane space,
the stroma,and the thylakoid space),The thylakoid membrane contains all of the
energy-generating systems of the chloroplast,In electron micrographs this membrane
appears to be broken up into separate units that enclose individual flattened vesicles
(see Figure 14-40),but these are probably joined into a single,highly folded membrane
in each chloroplast,As indicated,the individual thylakoids are interconnected,and they
tend to stack to form aggregates called grana,
(A) A wheat leaf cell in which a thin rim of cytoplasm containing chloroplasts surrounds
a large vacuole,(B) A thin section of a single chloroplast,showing the starch granules
and lipid droplets that have accumulated in the stroma as a result of the biosyntheses
occurring there,(C) A high-magnification view of a granum,showing its stacked thylakoid
membrane,(Courtesy of K,Plaskitt.)
Figure 7-42 Photosynthesis in a chloroplast,Water is oxidized
and oxygen is released in the photosynthetic electron-transfer reactions,while
carbon dioxide is assimilated (fixed) to produce carbohydrate in the carbon-
fixation reactions,
B,Photosynthesis
C,The antenna complex and photochemical reaction
center in a photosystem
Light-dependent reaction,Electron transport in the
thylakoid membrane and noncyclic
photophosphorylation,
Cyclic photophosphorylation:
Changes in redox potential during photosynthesis.
?Carbon dioxide fixation and the synthesis of
carbohydrate in C3 plants (Calvin cycle)
Figure 14-43 The initial reaction in carbon fixation,This reaction,in which
carbon dioxide is converted into organic carbon,is catalyzed in the chloroplast
stroma by the abundant enzyme ribulose bisphosphate carboxylase,The
product,3-phosphoglycerate,is also an important intermediate in glycolysis,the
two carbon atoms shaded in blue are used to produce phosphoglycolate when
the enzyme adds oxygen instead of CO2。
The structure and function in C4 plants
4,Organelle DNA and protein importing
A,Organelle DNA
?The size range of organelle DNA is similar to that of viral DNAs.
?Mit DNA,from <6,000bp (plasmodium falciparum) ～ >300,000bp (some land
plants),DNA of Mit genome (in mammals) ≈16,500bp(<0.001% of nuclear
genome) ; Chl genomes are about 10 times larger and contain about 120 genes.
?Chl DNA,from 70,000?to 200,000bp (genome of land plants);
?Genes in mtDNA encode rRNAs,tRNAs,and some
mitochondrial proteins
Human mt DNA,16,569bp
2 rRNAs,22 tRNAs,
13 polypeptides,NADH reductase,7 sub.
Cty b-c1 complex,1 cytb
Cyt oxidase,3 subunits
ATP synthase,2 F0 sub
Products of mt genes
are not exported
The organization of the liverwort(地钱 ) Chl genome
B,Mit and Chl have their own genetic systems
Mit and Chl are
organelles
semiautocephaly.
The synthesis of
mt proteins is
coordinated
C,The transport protein into Mit,And Chl,
?Tree proteins translocators in Mit membranes:
?TOM,TIM,and OXA complex
are multimeric membrane protein,
that catalyze protein transport
across Mit membrane,TOM,TIM
stand for translocase of the outer
and inner Mit membranes
respectively.
?TOM functions across the outer
membrane; TIM(TIM23 and
TIM22) function across the inner
membrane.
?OXA mediates the insertion of
inner membrane proteins that are
synthesized within the Mit,OXA
also helps TOM and TIM to insert
some proteins into the matrix.
?Translocation of precursors to the matrix occurs at
the sites where the outer and inner membranes are
close together;
?The protein import by Mit:
N-terminal signal sequence is recognized by receptors of TOM;
The protein is translocated across both Mit membranes at or near
special contact sites.
?Only unfolded proteins can be imported into Mit;
?Mit precursor proteins remain unfolded through interactions
with hsp70 chaperone proteins in the cytosol after they are
synthesized.
?ATP hydrolysis and H+ gradient are used to dtive
protein import into Mit
?Protein transport into the inner Mit membrane and
the intermembrane space requires two signal sequences
?Two signal
sequences are
required to
direct
proteins to
the Thylakoid
membrane in
Chl.
Translocation
into thylakoid
space or
thylakoid M can
occur by any
one of at least
four routes.
5,The proliferation and origin of Mit and Chl.
A,Organelle growth and division determine the
number of Mitochondria and Plastids in a cell
?Mit fission and fusion (a dividing Mit in a liver cell);
Dividing or Budding of Mit,
?Chloroplasts,dividing and formation of chloroplasts from
proplastids begins by the light-induced budding of the inner
membrane.
B,Origin,The endosymbiont theory
?Compare the ribosomal
RNA with the base sequence
of various bacterial rRNAs,
Purple bactria-Mitochondria
Cyanobacteria-Chloroplasts
Suggested evolutionary
pathway for the origin of
Mit.
