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Photophosphorylation differs from oxidative phosphorylation in that the former requires the input of energy in the form of ___________ to create a good electron donor. In photophosphorylation, electrons flow through a series of membrane-bound carriers including ___________ , ___________ , and ___________ proteins, whereas ___________ are pumped across a membrane to create an ___________ potential.
Light


cytochromes, quinones, iron-sulfur, protons, electrochemical.
Describe the effect(s) that a mitochondrial uncoupler such as 2,4-dinitrophenol (DNP) would have on photophosphorylation.
Uncouplers like DNP, which act by dissipating transmembrane proton gradients, would uncouple photophosphorylation because it is also dependent on a transmembrane proton gradient to provide the energy required to synthesize ATP from ADP and Pi.
Discuss how “accessory pigments” are able to extend the range of light absorption of the chlorophylls. Name some accessory pigments.
Accessory pigments are able to absorb light and transfer the absorbed energy to the chlorophylls in a process know as “exciton transfer.” Two accessory pigments are β-carotene and lutein.
What is an action spectrum, and what do peaks in an action spectrum signify? Show a typical action spectrum plot for photosynthesis.
An action spectrum is a plot of the effectiveness of a process (such as photosynthesis) versus wavelength of incident light. Its peaks signify the presence of a chromophore that absorbs light at that wavelength.
Describe what happens at photosystem I from the point where an antenna chlorophyll molecule absorbs a photon of light to the passage of an electron to NADP+.
The antenna chlorophyll molecule passes the energy of the photon, via exciton transfer, to neighboring chlorophyll molecules and ultimately to reaction center chlorophyll molecules. This excites P700 to P700*, which donates an electron to A0. From A0, electrons pass to phylloquinone (A1), through an Fe-S protein, to ferredoxin, then through a flavoprotein to NADP+.
P700* → A0 → A1 → Fe-S → NADP+ (See Figs. 19-43, p. 698, and 19-46, p. 703.)
Give five general classes of electron carriers that function in both mitochondrial electron transfer to O2 and photosynthetic electron transfer.
Any five of the following: pyridine nucleotides (NADH, NADPH); flavin nucleotides (FADH2, FMNH2); quinones (ubiquinone, plastoquinone); cytochromes; Fe-S proteins; flavoproteins.
The processes of oxidative phosphorylation coupled with electron transfer (in mitochondria) and photophosphorylation (in chloroplasts) resemble each other in certain respects. Describe five ways in which the two processes are similar, and describe three significant differences between the two processes.
Similarities include:
both contain a chain of membrane-bound electron carriers;

electron transfer leads to establishment of a proton gradient;

an ATPase/ATP synthase is a coupling factor;

ATP synthesis is sensitive to uncouplers;

both require a system of intact membranes to separate electrons inside and outside.

Differences include:

source of reducing power (NADH vs. light),

product (ATP in respiration; NADPH and/or ATP in photosynthesis);

source of oxidizing power (O2 in mitochondria; light in photosynthesis).
Show the path of electrons from photosystem II to NADPH in the chloroplast. What is the source of the energy that moves electrons through this path? Show where oxygen is involved in this pathway.
H2O → P680 → Pheophytin → PQA → PQB → cyt b6f complex → Plastocyanin → P700 → A0 → A1 → Fe-S → Ferredoxin → Ferredoxin-NADP+ oxidoreductase → NADP+.
The energy that drives the electron flow is from light. O2 is generated from H2O when H2O donates electrons to PSII.

O2 is generated by the splitting and oxidation of H2O, driven by the absorption of a photon by PSII (which occurs only in daylight). (See Fig. 19-49, p. 733.)
During photophosphorylation in plants, electrons flow through a series of carriers in the chloroplast. What is the ultimate donor of electrons, and what is the ultimate acceptor? What provides the energy to move those electrons?
The ultimate donor is H2O, and the acceptor, NADP+. The energy that drives this electron flow is from light.
Describe what happens when a photon is absorbed by photosystem II; end the description of electron flow at plastoquinone.
Absorption of a photon by PSII excites P680 to P680*, which passes an electron to pheophytin, which passes the electron to plastoquinone. P680, now lacking an electron, takes one away from a “water-splitting complex” of PSII, which in turn takes one from H2O. (See Fig. 19-56, p. 739.)
Chloroplasts are?
specialized plasids
What is the function of chloroplasts?
House the photosynthic machery

Gather light and make ATP + NADPH

carbon fixation takes place
What are the structures of chloroplasts?
Double membrane:
Outer membrane
Inner membrane

Internal Thylakoid membrane
What houses the photosynthic machery?
Thylakoid membrane
Thylakoid can be stacked or not stacked. What are the proper names?
Stacked – Grana
Unstacked – Lamellae
What is the Stroma?
fluid around thylakoid
Where are Kelvin enzymes are located?
Stroma
What are the major pigments in Chloroplasts?
Chlorophyll a

Phycoerythrobilin
What are the minor pigments in Chloroplasts?
lutein

Beta-carotene
What is the function of major pigments
in Chloroplasts?
Good at absorbing visable light

Excites e-
What is the function of minor pigments
in Chloroplasts?
Protect chlorophyll
Extend range of light plant can use
What does Light harvesting antennas do?
Collect light and pass energy to the rxn center
What does Exciton transfer with the help of light harvesting antennas?
Energy

Not transferring e-, but energy the e- had
What do rxn center of chloroplasts do?
Converts light energy to chemical energy

Redox rxn to get charge separation
What are the 6 steps to Conversion of light energy to chemical energy?
Excitons verses Electrons
Excitation by light
Exciton transfer in antenna
Exciton transfer to reaction center
Electron transfer
Charge separation
What are the steps in Z scheme?
Light strikes photosystem II and the energy is absorbed and passed along until it reaches P680 chlorophyll.

The excited electron is passed to the primary electron acceptor. Photolysis in the thylakoid takes the electrons from water and replaces the P680 electrons that were passed to the primary electron acceptor. ( O2 is released as a waste product)

The electrons are passed to photosystem I via the electron transport chain (ETC) and in the process used to pump protons across the thylakoid membrane into the lumen.

The stored energy in the proton gradient is used to produce ATP which is used later in the Calvin-Benson Cycle.

P700 chlorophyll then uses light to excite the electron to its second primary acceptor.

The electron is sent down another ETC and used to reduce NADP+ to NADPH.

The NADPH is then used later in the Calvin-Benson Cycle.
What does the z scheme accomplish?
E- transfer from H2O to NADP+ in non-cyclic photosynthesis
What is the position of cytochrome b6f in the Z scheme?
cytochrome b6f is the link between PSII and PSI in the Z scheme
What does cyt b6f is an integral?
membrane proton pump
What is the rxn formula in the Z scheme?
PS II ~~> cyt b6f complex ~~> PS I
What is another name for cytochrome b6f?
plastoquinol—plastocyanin reductase
The cytochrome b6f of chloroplasts and cyanobacteria does what?
transfers electrons between the two reaction center complexes of oxygenic photosynthetic membranes, photosystem I and photosystem II

participates in formation of the transmembrane electrochemical proton gradient by also transferring protons from the stromal to the internal lumen compartment.
The cytochrome b6f complex is responsible for?
"non-cyclic" and "cyclic" electron transfer between two mobile redox carriers, plastoquinol (QH2) and plastocyanin
What is cyt b6f composed of?
It is minimally composed of four subunits:
cytochrome b6 (carrying a low- and a high-potential heme groups (bL and bH))
cytochrome f with one covalently bound heme c;
Rieske iron-sulfur protein (ISP) containing a single [Fe2S2] cluster;
and subunit IV (17 kDa protein).
Facts of Type II Reaction Centers
Pheophytin ~~> Quinone

– P870

P870 ~~> Pheo ~~> Q ~~> cybc1 ~~> cyt c2 ~~> back to P870 to start over

No O2 donor needed since it is an cyclic electron flow
Cyclic electron flow of Type II Reaction Centers goes from?
Pheophytin ~~> Quinone
Type II Reaction Centers pathway is
P870 ~~> Pheo ~~> Q ~~> cybc1 ~~> cyt c2 ~~> back to P870 to start over
No O2 donor in Type II Reaction Centers needed since?
it is a cyclic electron flow
In its structure and functions, the cytochrome b6f complex bears extensive analogy to?
the cytochrome bc1 complex of mitochondria and photosynthetic purple bacteria.
What are the important differences between of the cytochrome b6f two complexes:
The single-polypeptide cytochrome b in the cytochrome bc1 complex corresponds to cytochrome b6 and subunit IV in the cytochrome b6f complex

Cytochrome f and cytochrome c1 are not homologous

The cytochrome b6f complex contains additional chromophores, chlorophyll a, β-carotene and atypical heme ci (heme x), the latter being linked by a single thioether bond to cytochrome b6
Green sulfur bacteria has what type of rxn center?
Type I
Facts of Type I Reaction Center
Fe – S cluster

Pigment at the center– P840

• Cyclic electron flow
• Noncyclic electron flow
The e – from Type I Reaction Center comes from either?
e- is from either Q or ferredoxin
Cyclic electron flow formula from Type I Reaction Center is?
P840 ~~> Q ~~> cyt bc1 ~~> cyt c553 ~~> P840
Non-Cyclic electron flow formula from Type I Reaction Center is?
H2S ~~> P840 ~~> Fd ~~> Fd-NAD redux ~~> NAD+ ~~> NADH + H +
Q from Cyclic electron flow formula from Type I Reaction Center does what?
cycles back and makes gradient to make ATP
Non-Cyclic electron flow Ferredoxin from Type I Reaction Center ends up in?
NADH
Position in the Z scheme in Photosystem I is
Second and heads upward
pathway of photosystem I is
Plastocyan ~~> P700 ~~> Ao ~~> Phylloquinone ~~> 3 Fe – S cluster ~~> Ferredoxin
Photosystem I facts:
Macromolecular structure

Antenna complex

P700

Plastocyan to P700 ~~> Ao ~~> Phylloquinone ~~> 3 Fe – S cluster ~~> Ferredoxin
What is the electron carriers used to transfer electrons from water to NADP+?
P680, Plastoquinone, cyt f, plastocyanin, P700, ferredoxin
Simple Non-cyclic electron flow Photosystem I pathway
plastocyanin ~> P700 ~> Ferredoxin ~> NADP+
In Photosystem I, What transferrs e- from ferredoxin to NADP+?
Fd-NADP+ oxidoreductase
Explain Cyclic electron flow
plastocyanin ~> P700 ~> Ferredoxin ~~> Fd PQ oxidoreductase and wind up back on PQ ~~> cyt b6f and pump more protons that end up back to plastocyanin producing ATP but not NADPH
Does photophosphorylation by cyclic electron flow around PSI produce O2?
No cause electron are recycled during this process so there is no need to oxidize H20
ATP synthase is made of what two important subunits for transporting H + thur matrix of Mitochondria
Complex Fo, F1
What make up the proton motive force?
A chemical (delta pH) and an electrical component make up the proton motive force.
ATP is synthesized from _____ by ______
ADP and Pi by ATP synthase in the inner mitochondria membrane.
ATP synthase takes place where?
in the inner mitochondria membrane.
Fo subunit of ATP synthase is what type of complex?
A membrane spanning protein complex
Where is F1 is located?
F1 is located on the matrix side of the inner membrane
Because the inner membrane is impermeable to H+, the only path for protons to reenter the matrix is through?
the pore formed by the Fo subunit of ATP synthase.
ADP is phosphorylated by the enzymatic activity of the _______ driven by_____.
F1 complex, driven by the PMF
What is Photosystem I Relation to the Z scheme?
Pumping protons either cyclic or non cyclic to generate ATP
What ends up in the grana of the thylakoid?
most PSII, cyt bcf, light harvesting complex II(P116) (LHCII )
most PSII, cyt bcf, light harvesting complex II(P116) (LHCII ) ends up here
the grana of the thylakoid
What ends up in the lamallae of the thylakoid?
PSI, ATP synthase, cyt b6f, LHCII
PSI, ATP synthase, cyt b6f, LHCII ends up here
Lamallae
What shows up in both the grana and lamellae?
LHCII (P116)
Why are PS I and PSII separated?
Prevention of exciton latency by spatial separation of PSI and PSII

better access to substrates

Control of electron flow via LHCII
exciton latency is?
Passing e- to the wrong photosystem
What PS requires less energy excitation?
PS I
What needs Access to substrates that is provided by Organization of photosynthetic complexes
ATP synthase needs access to ATP and Pi. (Out on lamellae, it is available to its substrates)

PSI ~~> NADP+
Why is organization of photosynthetic complexes
So important?
Prevents exciton latency and allows access to substrates
What is the result in a high ratio of reduced plastoquinone to oxidized plastoquinone (PQH2/PQ)
Over active of PSII and under active PSI

Over active of PSII, you will get reduced plastoquinone and not an oxidized plastoquinone
In regards to organization of photosynthetic complexes, controlling where LHCII is located will allow you to?
control where these photo e- are passed
What is Complex IV called?
Cytochrome c oxidase
Complex IV is composed of subunits and its molecular size is
13 subunits
204,000
How many Critical subunits of cytochrome c oxidase. (complex IV)
Three subunits
Critical subunits of cytochrome c oxidase.
(a) Subunit 1has two heme groups a and a3(red), and a Cu ion, CuB (green). The heme and Cu form a Fe-Cu Center.
(b) Subunit 2 (blue) has 2 Cu ions, CuA. Subunit 2 has the Cyt c binding site.
(c) Subunit 3 (green) is important but its function is not known.
What is in Subunit 1 of cytochrome c oxidase. (complex IV)?
Subunit 1 has two heme groups a and a3(red), and a Cu ion, CuB (green). The heme and Cu form a Fe-Cu Center.
In what subunit of Complex IV is the heme and Cu form a Fe-Cu Center?
Subunit 1
What is in Subunit 2 of cytochrome c oxidase. (complex IV)?
Subunit 2 has 2 Cu ions, (CuA & CuB), and the Cyt c binding site.
What is in Subunit 3 of cytochrome c oxidase. (complex IV)?
Subunit 3 is important but its function is not known.
In Complex 4, Where is the binuclear center of CuA located?
Subunit 2
What is different about the binuclear center of CuA of Complex IV?
The 2 Cu ions share electrons equally.
When the binuclear center of CuA of Complex IV is reduced, They are?
Cu+1, Cu+1.
When the binuclear center of CuA of Complex IV is oxidized they are?
Cu+1.5, Cu+1.5.
When the binuclear center of CuA of Complex IV is oxidized they are Cu+1.5, Cu+1.5. Why?
They share an electron
What is the Complex IV e- pathway?
2 molecules of reduced cytochrome c each donate an electron to binuclear center CuA.

Then the electrons are passed to heme a to the Fe-Cu center (cytochrome a3 and CuB).

O2 now binds to heme a3 and is reduced to its peroxy derivative (O2 2-) by 2 electrons from the Fe-Cu center.

Two more electrons from cyt c converts the (O2) 2- to two molecules of H2O with 4 H+ from the matrix.

In addition 4 more protons are pumped
from the matrix (N side) to to the P side by an
unknown mechanism.
Why must The complex I -IV have a intact membrane?
So e- won’t leak out and proton gradient can form
The Complex IV reaction may be thought of as?
4 cyt c (reduced) + 8 H+ N + O2 →4 cyt c (oxidized) + 4H+ P + 2 H2O
How much energy in formed by the complexs?
220 kJ/mol of energy is released and this energy is reserved by the set up of the proton gradient + separation of charges. (termed the Proton-motive force).
The energy formed by the complexs this energy is reserved by?
the set up of the proton gradient + separation of charges. (termed the Proton-motive force).
It is estimated that about 200 kJ/mole are conserved in the gradient.
What is the Proton-motive force?
the set up of the proton gradient + separation of charges from energy that is formed in the Complexs
The synthesis of ATP from ADP and Pi is driven by utilization of the energy generated by?
the proton gradient + the charge difference (electron potential) in the membrane
What is driven by utilization of the energy generated by the proton gradient + the charge difference (electron potential) in the membrane.
synthesis of ATP from ADP and Pi
The chemical mechanism that couples the energy obtained from the proton gradient to phosphorylation of ADP to form ATP is called the
chemiosmotic model or theory.
Explain the Chemiosmotic Model?
Electrons from NADH and other oxidizable substrates pass through a chain of carriers arranged
asymmetrically in the inner membrane.
Accompanying e- flow is a proton transfer
producing a pH (proton) gradient between the
intermembrane space and the matrix. Protons
are not permeable to the mitochondrial
membrane and can only get to the matrix
through a specific channel, Fo. The proton
motive force energy drives protons back into
the matrix providing energy for ATP synthesis that is catalyzed by ATP synthase.
What is the short explanation of Chemiosmotic Model?
Electrons from NADH and other oxidizable substrates pass through a chain of carriers arranged asymmetrically in the inner membrane.
In Chemiosmotic Model, Accompanying e- flow is a proton transfer producing?
a pH (proton) gradient between the intermembrane space and the matrix.
In Chemiosmotic Model, Accompanying e- flow is __________ producing a pH (proton) gradient between the intermembrane space and the matrix.
a proton transfer
Protons are not permeable to the mitochondrial
membrane and can only get to the matrix through by?
a specific channel, Fo.
In the Chemiosmotic Model, What drives protons back into the matrix providing energy for ATP synthesis that is catalyzed by ATP synthase.
proton motive force energy
In the Chemiosmotic Model, The proton motive force energy drives protons back into the matrix providing energy for ATP synthesis that is catalyzed by?
ATP synthase.
In the Chemiosmotic Model, The proton motive force energy drives protons back into the matrix providing?
energy for ATP synthesis


ATP synthesis is coupled to O2 consumption. Thus when a TCA metabolite or substrate metabolite is oxidized in the mitochondria (eg., succinate) the proton gradient occurs during O2 consumption driving ATP synthesis. That is why the process is called Oxidative Phosphorylation
ATP synthesis is coupled to?
O2 consumption.
when a TCA metabolite or substrate metabolite is oxidized in the mitochondria (eg., succinate) the
proton gradient occurs during?
O2 consumption driving ATP synthesis. That is why the process is called Oxidative Phosphorylation.
What is Oxidative Phosphorylation
The proton gradient occurs during O2 consumption driving ATP synthesis.
Coupling of electron transfer and ATP synthesis in mitochondria, Addition of ADP and Pi alone results in?
little or no increase in either O2 consumption or ATP synthesis
What causes causes immediate respiration and ATP synthesis in Oxidative Phosphorylation.
Succinate addition
What inhibits cytochrome oxidase, inhibits both O2 consumption and ATP synthesis in Oxidative Phosphorylation.
Addition of CN-
In Oxidative Phosphorylation, Succinate addition alone does not cause respiration but does occur when?
ADP + Pi are added
In Oxidative Phosphorylation,What blocks both ATP synthesis and respiration.
oligomycin and venturicidin
What are Inhibitors of ATP synthase,?
oligomycin and venturicidin
What does oligomycin and
Venturicidin do to in Oxidative Phosphorylation?
Inhibitors of ATP synthase
In Oxidative Phosphorylation,What allows respiration to go on but inhibits ATP synthesis?
dinitrophenol (DNP)
which is uncoupler compound
In Oxidative Phosphorylation, an uncoupler compound dinitrophenol (DNP) allows respiration to go on but inhibits ATP synthesis. This is because?
The uncoupler is able to dissipate the proton or pH gradient
In Oxidative Phosphorylation, an uncoupler compound dinitrophenol (DNP) does what?
allows respiration to go on but inhibits ATP synthesis.
How do the uncoupling agents, DNP and (FCCP) uncouple respiration from ATP synthesis?
both FCCP and DNP are Weak acids, having a dissociable H+ and are hydrophobic. This allows them to cross the mitochondrial membrane. They can carry protons across the membrane and dissipate the pH or proton gradient.
What allows FCCP and DNP to cross the mitochondrial membrane and can carry protons across the membrane and dissipate the pH or proton gradient.
both FCCP and DNP are Weak acids, having a dissociable H+ and are hydrophobic
What compounds interfere with oxidative phosphorylation?
Cyanide
Carbon monoxide
Antimycin A
Rotenone
Oligomycin
DNP
Cyanide interferes with oxidative phosphorylation

Type of interference:
Target/mode of action:
Type of interference: inhibition of electron transfer

Target/mode of action: inhibit cytochrome oxidase
Carbon monoxide interferes with oxidative phosphorylation

Type of interference:
Target/mode of action:
Type of interference: inhibition of electron transfer

Target/mode of action: inhibit cytochrome oxidase
Antimycin A interferes with oxidative phosphorylation

Type of interference:
Target/mode of action:
Type of interference: inhibition of electron transfer

Target/mode of action: Blocks electron transfer from cytochrome b to c1
Rotenone interferes with oxidative phosphorylation

Type of interference:
Target/mode of action:
Type of interference: inhibition of electron transfer

Target/mode of action: Prevent electron transfer from Fe-S center to ubiquinone
Oligomycin interferes with oxidative phosphorylation

Type of interference:
Target/mode of action:
Type of interference: Inhibition of ATP synthase
Target/mode of action: inhibits Fo and CFo
DNP interferes with oxidative phosphorylation

Type of interference:
Target/mode of action:
Type of interference: Uncoupling of phosphorylation from electron transfer

Target/mode of action: Hydrophobic proton carriers
What compounds have the inhibition of electron transfer-type of interference?
Cyanide
Carbon monoxide
Antimycin A
Rotenone
What compounds have the inhibit cytochrome oxidase - type mode of action?
Cyanide
Carbon monoxide
Can an artificially created proton gradient replace electron transfer and cause ATP Synthesis?
yes. Mitochondria can be manipulated to create a proton gradient in the absence of oxidizable substrate
and can cause ATP synthesis.
What is the evidence for the role of a proton
gradient in ATP synthesis?
First incubation. pH 9.0 buffer in presence of 0.1M
KCl.

Slow leakage of buffer and KCl into mito eventually brings the matrix into equilibrium w/ surrounjding medium

Second incubation.

Mitochondria is moved to Buffer of pH 7.0 w/ Valinomycin and no K+ added. The Valinomycin added to buffer is to transport K+
out of matrix creating a charge imbalance. This coupled with the proton gradient is sufficient to observe ATP synthesis.

The outward flow of K+ carried by Valinomycin down its concentration gradient w/o a counterion, creating a charge imbalance across the membrane

The sum of the chemical potential provided by the pH difference and the electrical potential provided by the separation of charges is a protonmotive force large enough to support ATP synthesis in the absence of an oxidizable substrate.
Describe the first incubation of the evidence for the role of a proton gradient in ATP synthesis?
First incubation. pH 9.0 buffer in presence of 0.1M
KCl. Slow leakage of buffer and KCl into mito eventually brings the matrix into equilibrium w/ surrounjding medium
Describe the Second incubation of the evidence for the role of a proton gradient in ATP synthesis?
Mitochondria is moved to Buffer of pH 7.0 w/ Valinomycin and no K+ added. The Valinomycin added to buffer is to transport K+
out of matrix creating a charge imbalance. This coupled with the proton gradient is sufficient to observe ATP synthesis.

The outward flow of K+ carried by Valinomycin down its concentration gradient w/o a counterion, creating a charge imbalance across the membrane
The sum of the chemical potential provided by the pH difference and the electrical potential provided by the separation of charges provided for the role of a proton gradient in ATP synthesis is a?
Proton motive force large enough to support ATP synthesis in the absence of an oxidizable substrate.
When the complex is solubilized and purified it causes?
hydrolysis of ATP to ADP and Pi.
When the complex is solubilized and purified it causes hydrolysis of ATP to ADP and Pi. When will the complex be able to synthesize ATP?
complex be able to synthesize ATP when the complex is situated in the mitochondria and in the presence of a proton gradient
There is a F0 integral membrane protein complex with subscript 0 indicationg that?
oligomycin inhibits the synthase by binding to the F0 complex.
F0 provides a transmembrane pore for?
protons.
Explain the F1 domain?
The F1 domain consists of three  subunits three  subunits and one delta subunit.

The  and subunits alternate with each other.

The central shaft is the y subunit that connects along
with the  subunit F1 to F0.

The F0 complex has 10 c subunits, an a and two b subunits.
The F1 domain consists of?

three  subunits three  subunits and one delta subunit.

The  and subunits of the F1 domain do what with each other?
alternate with each other.
The central shaft of the F1 domain is the y subunit that connects along with the?
 subunit F1 to F0.
The central shaft of the F1 domain is the? subunit
Y (delta)
The F0 complex has how many subunits?
10 c subunits, an a subunit and two b subunits.
how does the delta G’0 for ATP synthesis is close to 0?
ATP binds to the synthase at about Kd of 10-12 M while ADP binds only at only Kd of 10-5M.

This difference in binding corresponds to a difference of 40 kJ/mol in binding energy.

Because the hydrolysis of ATP in free solution is -30.5 kJ/mol, the relatively tight binding of ATP on the surface of the ATP synthase explains how the delta G’0 for ATP synthesis is close to 0
The beta subunit of the F1 complex can assume how many different conformations?
three
The subunit in the stalk is associated with?
one of the  subunits as well having one of its domain passing through F1.
What explains  subunits ability to bind ATP and ADP differently?
 subunits are in different conformations at all times

The subunit in the stalk is associated with one of the  subunits as well having one of its domain passing through F1. Thus the  subunits are?

in different conformations and this explains their ability to bind ATP and ADP differently.
Explain the different conformations of  subunits?
One has been found to bind ATP, another ADP
and the third has an empty site. Thus the conformations are known as - ATP, -ADP -empty and this has significance to the ATP synthase enzyme mechanism.
What are known as - ATP, -ADP -empty?
One  subunits has been found to bind ATP, another  subunits bind to ADP and the third  subunits has an empty site.
the and of the ATP synthase are ______ & ___________
in pairs and work together in the enzyme mechanics
What is the Binding Change Mechanism for ATP Synthesis?
A Rotational catalysis mechanism is proposed for ATP synthesis in where the active sites of F1 take turns catalyzing ATP synthesis. One  -subunit is in the ADP conformation, binding ADP + Pi. Another subunit has tightly bound ATP and the third −
subunit pair is empty.
The proton-motive force causes rotation of the central shaft subunit that comes into rotation with each −pair in succession. This causes?
each −pair to change in conformation.
The proton-motive force causes rotation of the central shaft subunit that comes into rotation with each −pair in succession. This causes each −pair to change in conformation. Name change of conformations?
−ATP becomes −empty releasing the ATP,

−ADP becomes −ATP and the ADP and Pi bound to it is converted to ATP.

The −empty site becomes −ADP which then loosely binds ADP +Pi.
all −pair sites alternate in activity and ATP cannot be released from one site until?
ADP and Pi are bound to another.
How many ATP are synthesized with oxidation of NADH and of succinate?
The overall reaction is: xADP + xPi + 1/2 O2 + H+ + NADH (increase) xATP + H2O + NAD+

X is sometimes called the P/O ratio or P/2e- ratio.
Explain the P/O ratio or P/2e- ratio?
In practical experiments it was found that the P/O ratio (= to ATP/ 1/2 O2 ) for NADH was between 2 and 3 and for succinate to be between 1 and 2. It was believed that one ATP was coupled with Complex I oxidation, another with complex III and one with complex IV. Thus the P/O ratio was 3.0. Since
The conformational changes for the model are driven by the passage of protons through the F0 portion of the ATP synthase.
The conformational changes for the binding change model are driven by?
the passage of protons through the F0 portion of the ATP synthase.
What causes rotation of the cylinder of c subunits and subunit in conformational changes for the binding change model?
the passage of protons through the F0 portion of the ATP synthase.
The subunit in contact with a −pair of the binding change model becomes?
a - empty subunit in conformation.