Chapter 18

No matter how many iron atoms there are, each cluster carries __#__ electron(s).

No matter how many iron atoms there are, each cluster carries *1 electron*.

Q, also known as _____, is _____ and diffuses rapidly in the _____ mitochondrial membrane.

Q, also known as *ubiquinone*, is *hydrophobic* and diffuses rapidly in the *inner* mitochondrial membrane.

Redox reactions allow the flow of _____ from _____ and _____ to _____, which is reduced to _____.

Redox reactions allow the flow of *electrons* from *NADH and FADH2* to *oxygen*, which is reduced to *water*.

The Q cycle funnels electrons from a 2-electron carrier (_____) to a 1-electron carrier (_____).

The Q cycle funnels electrons from a 2-electron carrier (*QH2*) to a 1-electron carrier (*cytochrome c*).

The availability of _____ and _____ control the rate of the citric acid cycle.

The availability of *NAD+* and *FAD* control the rate of the citric acid cycle.

standard free energy change using electron-transfer potential

just the top equation, but the Emax should be E'o

True or False: The role of proton gradient is to form ATP.

false The role of proton gradient is NOT to form ATP but to *release* it from synthase

True or False: Ubiquinone is the reduced form of coenzyme Q.

false; ubiquinone is the *oxidized* form of coenzyme Q

What are the cellular defense strategies used against reactive oxygen species (ROS)?

superoxide mutase and catalase

What do the shuttle systems do?

they are transport proteins that facilitate exchanges between the cytoplasm and the inner mitochondrial membrane

__#__ ATP is generated by conversion of pyruvate into acetyl CoA (inside the mitochondria).

*0* ATP is generated by conversion of pyruvate into acetyl CoA (inside the mitochondria).

__#__ ATP is generated by glycolysis.

*2* ATP is generated by glycolysis.

__#__ ATP is generated by the citric acid cycle.

*2* ATP is generated by the citric acid cycle.

_____ (decreases/increases) _____ consumption.

*2,4-dinitrophenol* (decreases/*increases*) *oxygen* consumption.

__#__ ATP is generated by oxidative phosphorylation (inside mitochondria).

*26* ATP is generated by oxidative phosphorylation (inside mitochondria).

__#__ of the complexes pump _____ from the _____ to the _____.

*3* of the complexes pump *protons* from the *mitochondrial matrix* to the *intermembrane space*.

__#__ electrons are funneled to O2, yielding H2O. The H in H2O come from _____ being pumped from the _____ to the _____.

*4* electrons are funneled to O2, yielding H2O. The H in H2O come from *protons* being pumped from the *matrix* to the *cytoplasm*.

__#__ molecules of (reduced/oxidized) cytochrome c bind to Complex __#__ to transfer electrons to convert __#__ O2 to H2O.

*4* molecules of (*reduced*/oxidized) cytochrome c bind to Complex *IV* to transfer electrons to convert *1*O2 to H2O.

_____ catalyzes the formation of ATP from ADP and Pi.

*ATP Synthase* catalyzes the formation of ATP from ADP and Pi.

_____ is synthesized when _____ flow back to the _____ through an enzyme complex called _____.

*ATP* is synthesized when *protons* flow back to the *matrix* through an enzyme complex called *ATP Synthase*.

_____ pumps protons in response to light. The interior of the vesicle becomes (alkalized/acidified) and then that drives a rotary nano-machine, the _____ and causes it to make ATP.

*Bacteriorhodopsin* pumps protons in response to light. The interior of the vesicle becomes (alkalized/*acidified*) and then that drives a rotary nano-machine, the *F1 ATPase* and causes it to make ATP.

_____ is extremely rich in _____; its _____ color is from _____+ and _____.

*Brown adipose tissue* is extremely rich in *mitochondria*; its *brown* color is from *red Hb* and *green cytochromes*.

_____ is a(n) _____ derivative with a long tail consisting of __#__ _____ units. Most mammals commonly have __#__ units.

*Coenzyme Q* is a(n) *quinone* derivative with a long tail consisting of *5* *isoprene* units. Most mammals commonly have *10* units.

_____ are newer and lower in energy. _____ are older and higher in energy.

*Cytochrome c* are new and lower in energy. *FeS clusters* are old and higher in energy.

_____ is a small, soluble protein that shuttles _____ from Complex __#__ to __#__, which is what catalyzes the reduction of _____.

*Cytochrome c* is a small, soluble protein that shuttles *electrons* from Complex *III* to *IV*, which is what catalyzes the reduction of *oxygen*.

_____ is present in all organisms that have _____ chains.

*Cytochrome c* is present in all organisms that have *mitochondrial respiratory* chains.

_____ of ANY _____ species reacts _____ w/ _____ of any other species that has been tested so far.

*Cytochrome c* of ANY *eukaryotic* species reacts *in vitro* w/ *cytochrome c oxidase* of any other species that has been tested so far.

_____ tightly holds onto _____ b/w _____ and _____ so as not to release _____ toxic species.

*Cytochrome oxidase c* tightly holds onto *O2* b/w *Fe* and *Cu ions* so as not to release *partially reduced O2* toxic species.

_____ are _____ transferring proteins that contain _____ prosthetic groups, which is identical to the _____ in _____ and _____.

*Cytochromes* are *electron* transferring proteins that contain *heme* prosthetic groups, which are identical to the *heme* in *Hb* and *Mb*.

_____ directly produces a _____ gradient.

*Electron transport chain* directly produces a *proton* gradient.

_____ can be determined by measuring _____ in _____.

*Electron-transfer potential* can be determined by measuring *electromotive force* in *sample half-cell*.

_____ is represented by E'o.

*Electron-transfer potential* is represented by E'o.

_____ are transferred from the (reduced/oxidized) form of _____ to O2, which is the final _____.

*Electrons* are transferred from the (*reduced*/oxidized) form of *cytochrome c* to O2, which is the final *electron acceptor*.

_____ flow in Complex I from _____ through _____ and a series of _____-_____ clusters to _____ (_____).

*Electrons* flow in Complex I from *NADH* through *FMN* and a series of *iron*-*sulfur* clusters to *ubiquinone* (*Q*).

_____ is a _____ subunit that spans the _____; it contains the _____ of the complex.

*F0* is a *hydrophobic* subunit that spans the *mitochondrial membrane*; it contains the *proton channel* of the complex.

_____ contains the catalytic activity of _____, consisting of __#__ types of _____ (_____, _____, _____, _____, _____).

*F1* contains the catalytic activity of *ATP Synthase*, consisting of *5* types of *polypeptide chains* (*alpha3, beta3, gamma, delta, epsilon*).

_____ enters Complex __#__ (_____) encountering the enzyme _____ first, which is present as an (integral/peripheral) protein of the (inner/outer) mitochondrial membrane.

*FADH2* enters Complex *II* (*Succinate-Q reductase*) encountering the enzyme *succinate DH* first, which is present as an (*integral*/peripheral) protein of the (*inner*/outer) mitochondrial membrane.

What happens during the first half of the Q cycle? What happens during the second half of the Q cycle?

*First Half of the Q Cycle* Q picks up its H's while facing inward toward the matrix. Then it flips over in the membrane so it is facing outward. QH2 binds to Qo binding site and gives 1 electron to cytochrome C1 and 1 electron to Q at the Qi binding site. Cytochrome C1 becomes cytochrome c. Q becomes Q.-. 2 protons from QH2 are released into the cytoplasm. The Q at the Qo binding site leaves and reenters the Q pool *Second Half of the Q Cycle* QH2 binds to the Qo binding site and gives 1 electron to cytochrome c and 1 electron to Q.-, which becomes QH2 after the uptake of 2 protons from the matrix. 2 protons from QH2 at the Qo binding site is released into the cytoplasm. The Q from the Qo binding site and the QH2 from the Qi binding site both reenter the Q pool.

_____ breaks the _____ hexamer; each _____ changes conformation as _____ rotates.

*Gamma* breaks the *alpha3-beta3* hexamer; each *beta* changes conformation as *gamma* rotates.

_____ shuttle carries _____ from cytoplasmic _____ across the mitochondrial membrane.

*Glycerol phosphate* shuttle carries *electrons* from cytoplasmic *NADH* across the mitochondrial membrane.

_____ is the compartment where most _____ and fatty acid oxidation reactions take place.

*Matrix* is the compartment where most *citric acid cycle* and fatty acid oxidation reactions take place.

_____ proposes the _____ and _____ are coupled by a(n) _____ across the mitochondrial membrane.

*Mitchell's chemiosmotic hypothesis* proposes the *ETC* and *ATP Synthase* are coupled by a(n) *H+ gradient* across the mitochondrial membrane.

_____ are bounded by double _____.

*Mitochondria* are bounded by double *membranes*.

Name the inhibitors of ETC and where they inhibit.

*NADH-Q oxidoreductase* - retenone - amytal *Cytochrome c oxidoreductase* - antimycin A *Cytochrome c oxidase* - CN- - N3- - CO

_____ of O2 can lead to _____ species.

*Partial reduction* of O2 can lead to *toxic* species.

_____ and _____ are _____ electron carriers that pick up _____ from each complex and deliver them to the next.

*Q* and *c* are *mobile* electron carriers that pick up *electrons* from each complex and deliver them to the next.

_____ is the bacteria that has the most mitochondrial-like _____.

*Rickettsia* is the bacteria that has the most mitochondrial-like *genome*.

_____ (such as _____), _____ electrons, having positive _____.

*Strong oxidizing agents* (such as O2), *accept* electrons, having positive *reduction potential*.

_____ (such as _____), _____ electrons, having negative _____.

*Strong reducing agents* (such as *NADH*), *donate* electrons, having negative *reduction potential*.

What are the 3 forms of the beta subunit in ATP Synthase? What does each form do?

*T (Tight)* Rotation of the gamma subunit by 120 degrees turns L into T, which causes the interconversion of ADP and Pi and ATP but does not allow ATP to be released. *O (Open)* Rotation of the gamma subunit by 120 degrees turns T into O, which allows ATP to be released. *L (Loose)* Rotation of the gamma subunit by 120 degrees turns O into L, which attracts and holds onto ADP and Pi.

__#__ of the __#__ complexes use energy from _____ to pump _____ from _____ to _____.

*Three* of the *four* complexes use energy from *electron flow* to pump *protons* from *the mitochondrial matrix* to *the intermembrane space*.

_____ permits the influx of _____ into the mitochondrial matrix without the synthesis of _____.

*UCP-1* permits the influx of *H+* into the mitochondrial matrix without the synthesis of *ATP*.

_____ of NADH and FADH2 is converted to _____ of ATP.

*electron-transfer potential* of NADH and FADH2 is converted to *phosphoryl-transfer potential* of ATP.

How many heme groups does cytochrome C1 have?

1

Name 2 uncouplers?

1. 2,4-dinitrophenol 2. gramicidin

What are all the different carriers?

1. ATP-ADP translocase 2. Dicarboxylate carrier 3. Tricarboxylate carrier 4. Pyruvate carrier 5. Phosphate carrier

The 4 complexes of the ETC

1. NADH-Q oxidoreductase 2. Succinate-Q reductase 3. Cytochrome c oxidoreductase 4. Cytochrome c oxidase

What are the other 3 names for the *F0-F1 complex*?

1. Racker's knob 2. ATP Synthase 3. Complex V

What are the 4 steps of Cytochrome IV mechanism?

1. Two molecules of cytochrome c sequentially transfer electrons to reduce *CuB* and heme *a3*. 2. Reduced CuB and Fe in heme a3 bind O2, which forms a *peroxide bridge*. 3. The addition of two more electrons and two more protons *cleaves* the peroxide bridge. 4. The addition of two more protons leads to the *release* of water.

What are the 4 steps of *ATP-ADP translocase*?

1. binding of cytoplasmic ADP to translocase 2. eversion of translocase 3. release of ADP into the matrix 4. subsequent binding of ATP from the matrix 5. eversion of translocase back to original conformation 6. release of ATP into the cytoplasm

What 2 things inhibit ATP synthase by preventing influx of H+ through ATP synthase?

1. oligomycin 2. DCC

What are the other processes controlled by proton gradients (proticity) besides ATP synthesis by ATP Synthase?

1. rotation of bacterial flagella 2. active transport of Ca by mitochondria 3. heat generation 4. NADPH synthesis

How much ATP is generated per Acetyl CoA?

10 ATP

How many residues make up cytochrome c? What's the number of residues that have been *invariable* for billions of years?

104, 21 invariant

How much ATP is generated per pyruvate?

12.5 ATP

How many heme groups does cytochrome b have?

2

How many protons are needed to propel one rotation of bacterial flagella?

256 protons

What is the overall chemical equation for catalase activity?

2H2O2 --> O2 + 2H2O

What is the overall reaction of the Q cycle?

2QH2 + Q + 2Cyt c(ox) + 2H+(matrix) = 2Q + QH2 + 2Cyt(red) + 4H+(cytoplasm)

ATP-ADP translocase may work in concert with the _____.

ATP-ADP translocase works in concert with the *phosphate carrier*.

How much ATP is generated in the brain?

30 ATP

How much ATP is generated in the kidney?

32 ATP

How many electrons in total are donated by 4 cytochrome c molecules in the Complex IV mechanism?

4 electrons

How many protons are taken from the mitochondrial matrix to convert each molecule of O2 to H2O?

4 protons are taken from the mitochondrial matrix to convert each molecule of O2 to 2 molecules of H2O.

How many protein complexes make up the electron transport chain? Are these protein complexes large?

4, yes

ATP-ADP translocase involves the influx of _____ and the outflux of _____. The influx only occurs if the outflux occurs.

ATP-ADP translocase involves the influx of *ADP* and the outflux of *ATP*. The influx only occurs if the outflux occurs.

A protein with FMN or FAD attached is called a _____.

A protein with FMN or FAD attached is called a *flavoprotein*.

What membrane protein facilitates ATP export? What inhibits ATP export?

ATP-ADP translocase atractyloside and bongkrekic

What is ATP-ADP translocase?

ATP-ADP translocase is a transport protein that enables ADP and ATP to move across the mitochondrial membrane by coupling their flow.

How many electrons does cytochrome c absorb? What does it do with these electrons?

Cytochrome c absorbs 4 electrons and uses these electrons to reduce O2 safely.

Complex __#__ (_____) catalyzes the transfer of _____ from _____ to (reduced/oxidized) _____ and pumps _____ out of the matrix.

Complex *III* (*Cytochrome c oxidoreductase*) catalyzes the transfer of *electrons* from *QH2* to (reduced/*oxidized*) *Cytochrome c* and pumps *protons* out of the matrix.

Complex __#__ contains __#__ types of cytochromes, which is/are _____.

Complex *III* contains *2* types of cytochromes, which is/are *b and C1*.

Complex __#__ involves the pumping of __#__ _____ to the cytoplasm.

Complex *III* involves the pumping of *2* *protons* to the cytoplasm.

Complex __#__, besides containing 2 cytochromes, also contains a(n) _____ cluster known as _____.

Complex *III*, besides containing 2 cytochromes, also contains a(n) *2Fe-2S* cluster known as *Rieske center*.

Complex __#__ (_____) catalyzes the (reduction/oxidation) of _____ to _____.

Complex *IV* (*Cytochrome c oxidase*) catalyzes the (*reduction*/oxidation) of *O2* to *H2O*.

Complex __#__ (_____) coordinates the flow of __#__ _____ from _____ to _____, which also pumps (in/out) __#__ _____ from the _____.

Complex I (*NADH-Q oxidoreductase*) coordinates the flow of *2* *electrons* from *NADH* to *coenzyme Q*, which also pumps (in/*out*) *4* *protons* from the *matrix*.

Why does FADH2 generate less energy than NADH?

Complex II, which deals with electrons from FADH2, does not pump out protons. Complex I, which deals with electrons from NADH, does pump out protons.

Which complex involves the *Q cycle*?

Complex III (Cytochrome c oxidoreductase)

Complex IV (_____) contains __#__ _____ and 3 _____.

Complex IV (*Cytochrome c oxidase*) contains *2* *heme A groups* and 3 *Cu ions*.

Complexes I, II, and III associate to form the _____, which is called _____.

Complexes I, II, and III associate to form the *supramolecular complex*, which is called *respirasome*.

Cooper centers alternate between _____ and _____ as it accepts and donates electrons.

Cooper centers alternate between *Cu2+*and *Cu+* as it accepts and donates electrons.

True or False: Cytochrome a is a heme group contained in a small water soluble protein that stays in the IM (intermembrane) space.

Cytochrome *c* is a heme group contained in a small water soluble protein that stays in the IM (intermembrane) space.

Which of the following can enter the Q pool? I. Q II. Q.- III. QH2 A. I only B. III only C. I and II only D. I and III only E. II and III only

D

Electrons from _____ and _____ through __#__ protein complexes to (reduce/oxidize) _____ to _____.

Electrons from from *NADH* and *FADH2* through *4* protein complexes to (*reduce*/oxidize) *oxygen* to *water*.

Do not use _____ for weight loss because it is _____.

Do not use *2,4-dinitrophenol* for weight loss because it is *toxic*.

path of electrons

NADH > FMN > [FeS]n > Q > bL > bH > FeS > C1 > c > CuA > a > a3 > CuB > O2 FADH2 > [FeS]n > Q > bL > bH > FeS > C1 > c > CuA > a > a3 > CuB > O2

Electrons move from (lower/higher) energy to (lower/higher) energy in the _____, which is divided into __#__ complexes.

Electrons move from (lower/*higher*) energy to (*lower*/higher) energy in the *ETC*, which is divided into *4* complexes.

What are the prosthetic groups in Succinate-Q reductase?

FAD Fe-S

What is the role of FAD+ in the glycerol phosphate shuttle?

FAD+ accepts the electrons from NADH and allows for the electron movement against the [NADH] gradient at the price of 1 ATP per 2 electrons.

What are the prosthetic groups in NADH-Q oxidoreductase?

FMN Fe-S

How are Fe-S complexes functionally different from quinones?

Fe-S complexes undergo redox without binding or releasing protons.

Fe4S4 is also found in _____.

Fe4S4 is also found in *Aconitase*.

For quinones, _____ reactions are coupled to _____ and _____.

For quinones, *electron-transfer* rxns are coupled to *proton binding* and *release*.

Function of _____ has been conserved for billions of years

Function of *cytochrome c* has been conserved for billions of years.

What's the difference between the glycerol phosphate shuttle and the malate aspartate shuttle?

Glycerol phosphate shuttle uses FAD+ as the electron acceptor, yielding 1.5 ATP. You get cheated out of ATP. Malate aspartate shuttle uses NAD+ as the electron acceptor, yielding 2.5 ATP. You don't get cheated out of ATP.

What are the prosthetic groups in Cytochrome c oxidase?

Heme a Heme a3 CuA and CuB

What are the prosthetic groups in Q-cytochrome c oxidoreductase?

Heme bH Heme bL Heme c1 Fe-S

High energy corresponds to a large (negative/positive) standard reduction potential.

High energy corresponds to a large (*negative*/positive) standard reduction potential.

If _____ is not needed, _____ are not going to flow from fuel molecules to _____.

If *ATP* is not needed, *electrons* are not going to flow from fuel molecules to *O2*.

In _____, _____ and complexes are found in _____, which is the (inner/outer) of __#__.

In *prokaryotes*, *electron transport chain pumps* and complexes are found in *cytoplasmic membrane*, which is the (*inner*/outer) of *two*.

In animals, the process of _____ oxidative phosphorylation from _____ to generate _____ occurs in what is called _____.

In animals, the process of *uncoupling* oxidative phosphorylation from *ATP synthesis* to generate *heat* occurs in what is called *Brown Adipose Tissue*.

In most tissues, _____ of glucose yields about __#__ ATP (__#__ in the heart and _____).

In most tissues, *oxidation* of glucose yields about *30* ATP (*32* in the heart and *liver*).

In the (first/second) half of the Q cycle, __#__ electrons of a (unbound/bound) _____ are transferred, 1 to _____ and the other to _____ to form _____.

In the (*first*/second) half of the Q cycle, *2* electrons of a(n) (unbound/*bound*) *QH2* are transferred, 1 to *cytochrome c* and the other to *bound Q in a second binding site* to form *the semiquinone radical anion (Q.-)*.

In the (first/second) half of the Q cycle, a second _____ gives up its _____ to complex __#__, one to a second molecule of _____ and the other to (reduce/oxidize) _____ to _____.

In the (first/*second*) half of the Q cycle, a second *QH2* gives up its *electrons* to complex *II*, one to a second molecule of *cytochrome c* and the other to (*reduce*/oxidize) *Q.-* to *QH2*.

In the Q cycle, the newly formed _____ dissociates and enters the _____.

In the Q cycle, the newly formed *Q* dissociates and enters the *Q pool*.

Iron ions in Fe-S complexes cycle b/w _____ (reduced) and _____ (oxidized) states.

Iron ions in these Fe-S complexes cycle b/w *Fe2+* (reduced) and *Fe3+* (oxidized) states.

What makes the *Rieske center* so unique?

It has 2 Histidine residues instead of 4 Cysteine residues. This stabilizes the center in reduced form, raising reduction potential.

What will ATP Synthase do in the absence of an H+ gradient?

It will use ATP to pump H+ from the matrix and into the intramembrane space.

Draw the three types of Fe-S clusters.

Know that the iron atoms are attached to the S of Cysteine, not S and then the S of Cysteine.

Draw the structure of *coenzyme Q*. What's another name for it?

Mammalian coenzyme Q commonly has a chain of 10 isoprene units. Another name for coenzyme Q is *ubiquinone*.

Mitochondria are _____, and parallel processes are found everywhere in _____.

Mitochondria are *symbiotic bacteria*, and parallel processes are found everywhere in *prokaryotic cells*.

Moving unit (_____) consists of the _____ and the _____.

Moving unit (*rotor*) consists of the *c ring* and the *gamma-epsilon stalk*.

What's the chemical formula for *peroxide*?

O2 ^2-

What's the chemical formula for *superoxide ion*?

O2.-

What is the overall chemical equation for superoxide mutase activity?

O2.- + 2H+ --> H2O2 + O2

Once _____ binds to Complex III at the _____ binding site and gives up all of its _____, it is fully (reduced/oxidized) and reenters the _____.

Once *QH2* binds to Complex III at the *Qo* binding site and gives up all of its *electrons*, it is fully (reduced/*oxidized*) and reenters the *Q pool*.

Oxidative phosphorylation involves the recycling of _____ to _____ for _____.

Oxidative phosphorylation involves the recycling of *ADP* to *ATP* for *energy*.

Oxidative phosphorylation regulation by ADP levels is known as _____.

Oxidative phosphorylation regulation by ADP levels is known as *respiratory control*.

Oxidative phosphorylation takes place in the _____ of the mitochondria which has two sides: the _____ and _____.

Oxidative phosphorylation takes place in the *inner membrane* of the mitochondria which has two sides: the *mitochondrial matrix* and *cytoplasm*.

Who was the theoretician behind the Chemi-osmotic Coupling Hypothesis?

Peter Mitchell

Some organisms can _____ oxidative phosphorylation from ATP synthesis to generate _____; it's a means of maintaining _____.

Some organisms can *uncouple* oxidative phosphorylation from ATP synthesis to generate *heat*; it's a means of maintaining *body temperature*.

The (inner/outer) membrane has highly folded ridges called _____, which provides (less/more) surface area.

The (*inner*/outer) membrane has highly folded ridges called *cristae*, which provides (less/*more*) surface area.

The _____ center linked by __#__ _____ residues accepts electrons from _____.

The *CuA* center linked by *2 Cysteine* residues accepts electrons from *reduced cytochrome c*.

The _____ center is linked by __#__ _____ residues and one modified _____.

The *CuB* center is linked by *3 Histidine* residues and one modified *Tyrosine*.

The _____ base rotates while the _____ head stands still.

The *F0* base rotates while the *F1* head stands still.

The _____ of cytochromes alternates between _____ (reduced/oxidized) and _____ (reduced/oxidized) states.

The *Fe ion* of cytochromes alternates between *Fe2+* (*reduced*/oxidized) and *Fe3+* (reduced/*oxidized*) states.

The _____ cycle takes place in Complex __#__.

The *Q* cycle takes place in Complex *III*.

The _____ from Complex III can accept electrons from _____.

The *Rieske center* from Complex III can accept electrons from *QH2*.

The _____ come from _____ and _____, which are found in the matrix.

The *electrons* come from *NADH* and *FADH2*, which are found in the matrix.

The _____ subunit is directly attached to the _____, so it rotates along with the _____.

The *gamma* subunit is directly attached to the *c ring*, so it rotates along with the *c ring*.

The _____ of _____ increases when _____ increases to meet the need for ATP.

The *rate* of *oxidative phosphorylation* increases when *[ADP]* increases to meet the need for ATP.

The F0-F1 complex consists of the _____ unit and the _____ unit.

The F0-F1 complex consists of the *moving* unit and the *stationary* unit.

The chain of 10 isoprene units is __#__ fatty acids long, which long enough to span the membrane. And it is very similar in structure to what you see in _____ membranes!

The chain of 10 isoprene units is *2* fatty acids long, which long enough to span the membrane. And it is very similar in structure to what you see in *Archaeal* membranes!

The first QH2 that binds to Complex III gives up 2 electrons. The first one goes from _____ to _____, which then turns into _____. The other one goes through _____ to (reduced/oxidized) _____, which then turns into _____.

The first QH2 that binds to Complex III gives up 2 electrons. The first one goes from *Fe-S clusters* to *cytochrome C1*, which then turns into *cytochrome c*. The other one goes through *b heme* to (reduced/*oxidized*) *ubiquinone*, which then turns into *Q.-*.

The intramembrane space is relatively (basic/acidic).

The intramembrane space is relatively (basic/*acidic*).

The overall reaction of oxidative phosphorylation is (endergonic/exergonic).

The overall reaction of oxidative phosphorylation is (endergonic/*exergonic*).

What does the phrase "get cheated out of ATP" refer to?

The phrase refers to the glycerol phosphate shuttle, which carries electrons from cytoplasmic NADH across the inner mitochondrial membrane. Cytoplasmic NADH only yields 1.5 ATP as opposed to the usual 2.5 ATP yielded by matrix NADH. This is because the shuttle takes the electrons from NADH and puts them on FAD+, which acts as the electron acceptor rather than NAD+.

What is the *proton motive force*?

The proton gradient created by ETC causes protons to flow down the pH/charge electrochemical gradient through F0-F1 complex, which serves as the driving force for the phosphorylation of ADP to ATP.

The protons flow back in through the mitochondrial (inner/outer) membrane, driving protein-based machinery, which causes _____ to be synthesized.

The protons flow back in through the mitochondrial (*inner*/outer) membrane, driving protein-based machinery, which causes *ATP* to be synthesized.

The protons return to the matrix by flowing through another protein complex, _____, powering the synthesis of _____.

The protons return to the matrix by flowing through another protein complex, *ATP Synthase*, powering the synthesis of *ATP*.

The pumping of protons results in (unequal/equal) distribution of _____, which forms a _____ gradient/electric _____.

The pumping of protons results in (*unequal*/equal) distribution of *H+*, which forms a *pH* gradient/electric *membrane potential*.

What are the 2 binding sites on Complex III called? What binds to each binding site?

The two binding sites on Complex III are Qo and Qi. QH2 binds to Qo. Q binds to Qi.

Why do the heme groups of cytochrome b differ in electron affinity?

Their difference in electron affinity is due to the difference in environment.

There are two compartments of the mitochondria: _____ and _____.

There are two compartments of the mitochondria: *intermembrane space* and *matrix*.

Together, _____ and _____ form the active center where O2 is converted to H2O.

Together, *a3* and *CuB* form the active center where O2 is converted to H2O.

Two _____ bind to Complex III, each giving up _____ and _____. The _____ go to the cytoplasm.

Two *QH2 molecules* bind to Complex III, each giving up *2 electrons* and *2 protons*. The *protons* go to the cytoplasm.

Uncoupling of _____ from ATP synthesis is done by _____, which carries _____ (down/up) its _____ across the mitochondrial membrane; _____ works but _____ is not formed because there's no _____.

Uncoupling of *electron transport* from ATP synthesis is done by *2,4-dinitrophenol*, which carries *H+* (*down*/up) its *concentration gradient* across the mitochondrial membrane; *electron transport* works but *ATP* is not formed because there's no *proton force*.

When coenzyme Q accepts __#__ _____ from _____, it also takes up __#__ _____ from the _____, forming _____, which is the (reduced/oxidized) form called _____.

When coenzyme Q accepts *2* *electrons* from *NADH*, it also takes up *2* *protons* from the *matrix*, forming *QH2*, which is the (*reduced*/oxidized) form called *ubiquinol*.

When the _____ gradient is high enough, _____ force their way back into the matrix through the _____ (_____).

When the *proton* gradient is high enough, *protons* force their way back into the matrix through the *F0-F1 complex* (*Racker's knob*).

What are the 2 Heme A groups?

a and a3

What is gramicidin?

an antibiotic that acts as an uncoupler of electron transport from ATP synthesis it collapses the proton gradient by making a hole for protons to travel through

What is UCP-1?

an uncoupling protein found in brown adipose tissue by allowing the influx of H+ into the mitochondrial matrix without the synthesis of ATP

Which side of ATP-ADP translocasedoes atractyloside and bongkrekic bind to?

atractyloside = cyto side bongkrekic = matrix side

cellular respiration = _____ + _____ + _____

cellular respiration = *citric acid cycle* + *electron transport chain* + *ATP synthesis*

True or False: ATP-ADP exchange is energetically favorable.

false ATP-ADP exchange is energetically costly

True or False: NADH is stripped of its electrons by Complex I and leaves the complex. FADH2 is stripped of its electrons by Complex II and leaves the complex.

false Although the first statement is true, the second statement if false. FADH2 is stripped of its electrons by Complex II, but it doesn't leave the complex.

True or False: Complex II (Succinate-Q oxidase) pumps protons from one side of the membrane to the other.

false Complex II (Succinate-Q *reductase*) *does not* pump protons from one side of the membrane to the other.

True or False: Complex IV only uses 4 protons in each of its cycles.

false It uses 4 protons to convert O2 to 2H2O and pumps 4 protons out into the cytoplasm, contributing to the proton gradient.

True or False: Japanese researchers proved that ATP breakdown causes ATP Synthase to run backwards. This got them a Nobel Prize.

false Japanese researchers provided a theory that had been made by John E. Walker and Paul D. Boyer many years earlier. Therefore, John E. Walker and Paul D. Boyer got the Nobel Prize.

True or False: The first electron transfer of the Q cycle results in the uptake of two protons from the cytoplasm.

false The *second* electron transfer of the Q cycle results in the uptake of two protons from the *matrix*.

True or False: The electrons from FADH2 are transferred to FMN and then [FeS]n.

false The electrons from FADH2 are transferred to FeS directly.

True or False: The heme groups from Complex IV are identical to the heme groups in Hb and Mb.

false The heme groups from Complex IV are *different* from the heme groups in Hb and Mb.

True or False: The reduction of O2 to H2O is an unfavorable reaction.

false The reduction of O2 to H2O is a *favorable* reaction.

What are the 2 shuttle systems?

glyerol phosphate shuttle malate aspartate shuttle

What is the role of the b2 shaft in "Racker's Knob"?

holds F1 still while the c ring of F0 is rotating

Where was brown fat *formerly* thought to only be found?

human babies

Where is the *malate aspartate shuttle* typically found in the human body?

liver and heart

Where is the *glycerol phosphate shuttle* typically found in the human body?

muscle

What term did Peter Mitchell invent?

proticity as a parallel for electricity

What are *chemical protons*?

protons from the matrix that are used to convert O2 to 2H2O

In "Racker's Knob", what is the stator and what is the rotor?

stator = a rotor = c ring

True or False: Protons flow through *half-channels* of the c ring.

true

True or False: The heme groups from Complex IV are different from the heme groups from Complex III.

true