What is the major shuttle in most tissues?
glycerol 3-phosphate shuttle
What is the function of cytosolic glycerophosphate dehydrogenase?
converts DHAP to glycerol 3-phosphate
Where is glycerol 3-phosphate converted to DHAP? By what enzyme?
inner mitochondrial membrane
mitochondrial glycerophosphate dehydrogenase
What redox reaction takes place during the creation of glycerol 3-phosphate?
NADH + H+
NAD+
What redox reaction takes place during the creation of DHAP?
FAD
FADH2
Which shuttles are primarily used in the heart and liver?
aspartate-malate shuttle
How many ATP is yielded by asparate-malate shuttle?
3 ATP
Where are the TCA cycle enzymes located?
matrix (center) of mitochondria
Which of the mitochondrial membranes is permeable to most molecules?
outer membrane
What are the folds in the inner membrane of the mitochondria called?
cristae
Where are the enzymes of the ETC and ATP synthase found?
inner membrane of the mitochondria
What is the function of the cristae?
increase membrane surface area
create chemical gradients
What is the function of the electron transport chain?
regenerate NAD+ and FAD with free energy released used to generate ATP and the reduction of oxygen to water
What are 2 names of complex I?
NADH dehydrogenase
NADH-Q-reductase
Does complex 1 span the membrane?
yes
What are the 2 functions of Complex I?
oxidize NADH
reduce Coenzyme Q
What comprises the Fe-S complex?
4 iron atoms and 4 sulfer atoms
What are 2 names of complex II?
succinate dehydrogenase
succinate-Q reductase
Does complex II span the membrane?
no
What is the function of complex II?
oxidize succinate via the generation of FADH2
reduce Coenzyme Q
What are 2 names of complex III?
cytochrome b-c1 complex
Coenzyme Q-cyt c-reductase
What are 2 functions of complex III?
oxidize Coenzyme Q
reduce Cytochrome c
Is complex III a membrane spanning complex?
yes
Which complexes contain heme?
complex III
complex IV
What are 2 names of complex IV?
cytochrome a-a3 complex
cytochrome c oxidase
What are 2 functions of complex IV?
oxidize cytochrome c
reduce oxygen to water
Which complex has a binding site for oxygen?
complex IV
Is complex IV a membrane spanning complex?
yes
What type of iron complex is in complex IV?
heme A
Why is there copper in heme A?
facilitates the collection of the 4 electrons required to reduce molecular oxygen
What are the 2 mobile electron carriers required for the ETC?
Coenzyme Q
cytochrome c
What is another name for Coenzyme Q?
ubiquinone
What is cytochrome C?
small heme protein
Where is cytochrome C found?
intermembrane space side of inner membrane of mitochondria
What is the function of cytochrome c?
electron shuttle between complex III and complex IV
What type of heme is on cytochrome C?
heme C
Name the 2 flavin coenzymes
FMN (complex I)
FAD (complex II)
Which electron carrier of the ETC is a quinone derivative?
coenzyme Q
Which 3 electron carriers of the ETC contain iron-sulfur complexes?
complex I
complex II
complex III
In the ETC, which has a more positive redox potential: donor or acceptor?
acceptor
What is the pathway of NADH?
complex I
CoQ
complex III
cyt c
complex IV
oxygen
What is the pathway of FADH2?
complex II
CoQ
complex III
cyt c
complex IV
oxygen
What is inhibited by rotenone? Describe the mechanism
insecticide inhibits complex I
inhibits donation of electrons from FeS to CoQ
What is inhibited by antimycin A? Describe the mechanism
complex III
inhibits donation of electron to cyt c
Name 4 inhibitors of complex IV?
cyanide
azide
hydrogen sulfide
carbon monoxide
What is the difference between the inhibitory action of hydrogen sulfide and carbon monoxide?
hydrogen sulfide: binds to Fe3+
carbon monoxide: binds to Fe2+
Why does iron deficiency lead to inhibition of the ETC (2)?
no iron for cytochromes
no iron for Fe-S
What is the result of inhibition of complex IV?
build up of reduced components in all complexes
What is Mitchell's chemiosmotic theory?
explains the process of oxidative phosphorylation (conversion of ADP to ATP)
Which complexes use energy to pump H+ across the inner membrane? How many each?
I: 4H+
III: 4H+
IV: 2H+
What 2 components make up the proton motive force?
electrochemical potential gradient
H+ gradient
Where is ATP synthase located?
inner membrane of the mitochondria
What is the function of ATP synthase?
facilitates the reentry of H+ into the matrix
How is ATP formed by ATP synthase?
relieves pH and electrical gradients
What are the 2 portions of ATP synthase?
F0 (pore)
F1 (head)
What forms the proton channel?
a and c subunits of F0
Where is the catalytic site for ATP synthase found?
beta-subunit of F1
What acts as the rotor during ATP synthesis?
gamma-subunit of F1
What are the 3 conformations of ATP synthase?
empty
ADP + Pi bound
ATP release
How many protons are required for one full turn of ATP synthase?
12 protons
How many ATP are generated from a single turn of ATP synthase?
3 ATP
What is oligomycin?
antibiotic inhibitor of ATP synthase
Describe the mechanism of oligomycin?
binds to F0 portion and inhibits re-entry of protons into matrix by closing the channel
How much ATP is yielded from the glycerol 3-phosphate shuttle?
2 ATP
What redox reaction occurs in the formation of cytosolic malate?
NADH + H+
NAD+
What redox reaction occurs in the formation of mitochondrial oxaloacetate?
NAD+
NADH + H+
In relation to the aspartate-malate shuttle, how do molecules cross the inner mitochondrial membrane?
specific translocases
Name 2 pairs of molecules that use translocases to traverse the inner mitochondrial membrane
malate/a-ketoglutarate
glutamate/aspartate
Describe the structure of Coenzyme Q and its function
non-protein lipid soluble molecule
link between complex I or II and Complex III
Why is coenzyme Q like a funnel?
accepts 2 electrons from donors and releases a single electron to the cytochromes
Name the heme containing cytochromes
cytochrome b and c1 (complex III)
cytochrome c
cytochrome a and a3 (complex IV)
What energy drives the pumping of H+ across the inner membrane?
electron transfer from one redox pair to the next
What is the major shuttle in most tissues?
glycerol 3-phosphate shuttle
What is the function of cytosolic glycerophosphate dehydrogenase?
converts DHAP to glycerol 3-phosphate
Where is glycerol 3-phosphate converted to DHAP? By what enzyme?
inner mitochondrial membrane
mitochondrial glycerophosphate dehydrogenase
What redox reaction takes place during the creation of glycerol 3-phosphate?
NADH + H+
NAD+
What redox reaction takes place during the creation of DHAP?
FAD
FADH2
Which shuttles are primarily used in the heart and liver?
aspartate-malate shuttle
How many ATP is yielded by asparate-malate shuttle?
3 ATP
Where are the TCA cycle enzymes located?
matrix (center) of mitochondria
Which of the mitochondrial membranes is permeable to most molecules?
outer membrane
What are the folds in the inner membrane of the mitochondria called?
cristae
Where are the enzymes of the ETC and ATP synthase found?
inner membrane of the mitochondria
What is the function of the cristae?
increase membrane surface area
create chemical gradients
What is the function of the electron transport chain?
regenerate NAD+ and FAD with free energy released used to generate ATP and the reduction of oxygen to water
What are 2 names of complex I?
NADH dehydrogenase
NADH-Q-reductase
Does complex 1 span the membrane?
yes
What are the 2 functions of Complex I?
oxidize NADH
reduce Coenzyme Q
What comprises the Fe-S complex?
4 iron atoms and 4 sulfer atoms
What are 2 names of complex II?
succinate dehydrogenase
succinate-Q reductase
Does complex II span the membrane?
no
What is the function of complex II?
oxidize succinate via the generation of FADH2
reduce Coenzyme Q
What are 2 names of complex III?
cytochrome b-c1 complex
Coenzyme Q-cyt c-reductase
What are 2 functions of complex III?
oxidize Coenzyme Q
reduce Cytochrome c
Is complex III a membrane spanning complex?
yes
Which complexes contain heme?
complex III
complex IV
What are 2 names of complex IV?
cytochrome a-a3 complex
cytochrome c oxidase
What are 2 functions of complex IV?
oxidize cytochrome c
reduce oxygen to water
Which complex has a binding site for oxygen?
complex IV
Is complex IV a membrane spanning complex?
yes
What type of iron complex is in complex IV?
heme A
Why is there copper in heme A?
facilitates the collection of the 4 electrons required to reduce molecular oxygen
What are the 2 mobile electron carriers required for the ETC?
Coenzyme Q
cytochrome c
What is another name for Coenzyme Q?
ubiquinone
What is cytochrome C?
small heme protein
Where is cytochrome C found?
intermembrane space side of inner membrane of mitochondria
What is the function of cytochrome c?
electron shuttle between complex III and complex IV
What type of heme is on cytochrome C?
heme C
Name the 2 flavin coenzymes
FMN (complex I)
FAD (complex II)
Which electron carrier of the ETC is a quinone derivative?
coenzyme Q
Which 3 electron carriers of the ETC contain iron-sulfur complexes?
complex I
complex II
complex III
In the ETC, which has a more positive redox potential: donor or acceptor?
acceptor
What is the pathway of NADH?
complex I
CoQ
complex III
cyt c
complex IV
oxygen
What is the pathway of FADH2?
complex II
CoQ
complex III
cyt c
complex IV
oxygen
What is inhibited by rotenone? Describe the mechanism
insecticide inhibits complex I
inhibits donation of electrons from FeS to CoQ
What is inhibited by antimycin A? Describe the mechanism
complex III
inhibits donation of electron to cyt c
Name 4 inhibitors of complex IV?
cyanide
azide
hydrogen sulfide
carbon monoxide
What is the difference between the inhibitory action of hydrogen sulfide and carbon monoxide?
hydrogen sulfide: binds to Fe3+
carbon monoxide: binds to Fe2+
Why does iron deficiency lead to inhibition of the ETC (2)?
no iron for cytochromes
no iron for Fe-S
What is the result of inhibition of complex IV?
build up of reduced components in all complexes
What is Mitchell's chemiosmotic theory?
explains the process of oxidative phosphorylation (conversion of ADP to ATP)
Which complexes use energy to pump H+ across the inner membrane? How many each?
I: 4H+
III: 4H+
IV: 2H+
What 2 components make up the proton motive force?
electrochemical potential gradient
H+ gradient
Where is ATP synthase located?
inner membrane of the mitochondria
What is the function of ATP synthase?
facilitates the reentry of H+ into the matrix
How is ATP formed by ATP synthase?
relieves pH and electrical gradients
What are the 2 portions of ATP synthase?
F0 (pore)
F1 (head)
What forms the proton channel?
a and c subunits of F0
Where is the catalytic site for ATP synthase found?
beta-subunit of F1
What acts as the rotor during ATP synthesis?
gamma-subunit of F1
What are the 3 conformations of ATP synthase?
empty
ADP + Pi bound
ATP release
How many protons are required for one full turn of ATP synthase?
12 protons
How many ATP are generated from a single turn of ATP synthase?
3 ATP
What is oligomycin?
antibiotic inhibitor of ATP synthase
Describe the mechanism of oligomycin?
binds to F0 portion and inhibits re-entry of protons into matrix by closing the channel
How much ATP is yielded from the glycerol 3-phosphate shuttle?
2 ATP
What redox reaction occurs in the formation of cytosolic malate?
NADH + H+
NAD+
What redox reaction occurs in the formation of mitochondrial oxaloacetate?
NAD+
NADH + H+
In relation to the aspartate-malate shuttle, how do molecules cross the inner mitochondrial membrane?
specific translocases
Name 2 pairs of molecules that use translocases to traverse the inner mitochondrial membrane
malate/a-ketoglutarate
glutamate/aspartate
Describe the structure of Coenzyme Q and its function
non-protein lipid soluble molecule
link between complex I or II and Complex III
Why is coenzyme Q like a funnel?
accepts 2 electrons from donors and releases a single electron to the cytochromes
Name the heme containing cytochromes
cytochrome b and c1 (complex III)
cytochrome c
cytochrome a and a3 (complex IV)
What energy drives the pumping of H+ across the inner membrane?
electron transfer from one redox pair to the next