Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Biochemistry Exam III material > Oxidative phosphorylation II > Flashcards

Oxidative phosphorylation II Flashcards

1
Q

Protons are pumped across what membrane as they flow through the Respiratory chain

A

the inner mitochondrial membrane

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What is the chemiosmotic hypothesis

A
  • Purposed by Peter Mitchell in 1961
  • ETC is accompanied by transport of protons from matrix to cytoplasmic side of inner membrane
  • This generates a pH gradient and membrane potential
  • Constitutes a proton motive force
    • composed of two comments:
      - chemical gradient (pH gradient)
      - charge gradient
    • used to dive ATP synthesis (via ATP synthase)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

what was used to supply evidence for the chemiosmotic hypothesis

A
  • Synthetic phospholipid vesicles containing Bacteriorhodopsin and mitochondrial ATP synthase purified form beef heart were created
  • purified ATP synthase and bacteriorhodopsin reconstituted into the vesicles (bacteriorhodopsin pumps protons when illuminated)
  • Incubated with ADP+Pi
  • Exposed to light and ATP generated
  • — experiment clearly showed that the respiratory chain and ATP synthase are biochemically separate systems, linked only by a proton-motive force
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

The F0 unit of the ATP synthase is located

A

embedded in the inner mitochondrial membrane

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

The F1 unit of ATP synthase is located

A

protrudes into the mitochondrial matrix

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

The F1 subunit of ATP synthase consists of ____ types of polypeptide chains

A

5 (alpha3, beta3, gamma, delta, and epsilon)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

The alpha and beta components of subunit F1 in ATP synthase are arranged alternately in a

A

hexameric ring

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Which of the ATP synthase subunits contain catalytic domains

A

F1

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What is complex V of the ETC

A

ATP synthase

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

ATP synthase is a ____ and ____ structure

A

ball and stick

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What is the stick component of the ATP synthase

A

F0

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

what is the ball component of the ATP synthase

A

F1

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Which of the subunits in ATP synthase have proton channels

A

F0

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

does Isolated F1 subunit displays ATPase activity

A

Yes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Both Alpha and Beta on F1 bind nucleotides but only the ____ are catalytically active

A

Beta

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Above the alpha and beta is a stalk made of ____ and ____ proteins

A

gamma and epsilon

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

The gamma subunit has a long helical coil that extends into the

A

center of the alpha3 and beta3 hexamer

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What breaks the symmetry of the beta3alpha hexamer: each of the Beta subunits is distinct by virtue of its interaction with a different face of the _____

A

The gamma subunit, gamma subunit

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

The F0 has a proton channel complex. This channel consists of a ring comprising from ____ c subunits that are embedded in the matrix

A

8-14 c subunits

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

F0 and F1 are subunits of ATP synthase are connected by what two ways

A
  • by the central gamma/epsilon stalk

- by an exterior column consists of one alpha subunit, two beta subunits, and the delta subunit

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

ATP synthase molecules associate with each other to form

A

dimers

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

ATP synthase dimers come together to form

A

oligomers

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What is the purpose of ATP synthase molecules associating with one another to form dimers and then oligomers

A
  • association stabilizes the individual enzymes to the rotational forces required for catalysis and facilitates the curvature of the inner mitochondrial membrane
  • maintains curvature in inner membrane
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

The ATP synthases are located

A

at the tips of the crust, thereby enhancing the efficiency of ATP synthesis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

-Cristae allow the proton gradient to be in ____ proximity to the ATP synthase

A

close

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

What is the role of the proton gradient in ATP synthase

A

ATP can be formed in the absence of proton gradient but it can’t leave the catalytic site unless protons flow through the enzyme. Thus the role of the proton gradient is not to form ATP but to release it form the synthase

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

ATP synthase when incubated with ADP and Pi forms

A

ATP in the absence of the proton gradient

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

How many active sites are there on the ATP synthase

A

3 (the beta3 units of the F1 subunit)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

What is the moving unit of the ATP synthase

A

The moving unit, or rotor, consists of the c ring and the gamma epsilon stalk

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

The three beta subunits can each perform three sequential steps in the synthesis of ATP by

A

Changing conformations

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

What are the three sequential steps in ATP synthesis

A
  1. ) ADP and Pi binding
  2. ) ATP synthesis
  3. ) ATP release
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

What is the O conformation in the beta subunit

A

it is the open conformation. This allows for the release of ATP and for ADP and Pi to enter the subunit

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

What is the L conformation in the beta subunit

A

Loose, Has a strong binding affinity for ADP and Pi thus locking them in the subunit

34
Q

What is the T conformation in the beta subunit

A

Tight, has a strong affinity for the ATP and actually drives ADP and Pi together to form ATP

35
Q

How much does the gamma subunit rotate to move conformation states in the beta subunits

A

counterclockwise 120 degrees

36
Q

each beta subunit progresses from ___ to ___ to ___ conformation

A

T,O,L

37
Q

Are any two beta subunits ever in the same conformation state

A

No

38
Q

What powers the rotation of the c ring on ATP synthase F0 subunit

A

The movement of protons through the half channels from the high proton concentration of the cytoplasm to the low proton concentration of the matrix powers the rotation of the c ring.

39
Q

The c subunit of ATP synthase is composed of

A
  • 2 alpha helices that span the membrane.
  • Aspartic acid (glutamic acid) residue in one of the helices lies on the center of the membrane (these bind to the protons)
40
Q

how many a subunits bind to the outside of the ring (8-14 c subunits)

A

a single a subunit

41
Q

When glutamate is in a high proton environment it will ____

A

bind the proton

42
Q

if glutamate is charged (unprotonated) the c subunit will

A

not move into the membrane

43
Q

Does the a unit rotate with the c ring

A

no

44
Q

The a subunit is composed of

A

2 half channels, that allow protons to enter and pass partway but not completely

45
Q

The alpha and beta subunits of ATP synthase are members of the ______ family of proteins

A

P-loop NTPase family

46
Q

Is the regeneration of NAD+ for use in glycolysis one function of the ETC

A

Yes

47
Q

The major function of oxidative phosphorylation is to generate

A

ATP from ADP

48
Q

Do ATP and ADP readily move across the inner mitochondrial membrane into the cytoplasm

A

No (ATP-ADP translocase is used)

49
Q

What enables ATP and ADP to transverse the permeability barrier (inner mitochondrial membrane)

A

ATP-ADP translocase

50
Q

Mechanism of mitochondrial ATP-ADP translocase

A
  • Catalyzes the coupled entry of ADP into the matrix and the exit of ATP from it
  • The binding of ADP form the cytoplasm favors eversion of the transporter to release ADP into the matrix.
  • Subsequent binding of ATP from the matrix to the everted from favors eversion back to the original conformation, releasing ATP into the cytoplasm
51
Q

The flow of ATP and ADP are

A

coupled, ADP enters the mitochondrial matrix only if ATP exits, and vice versa.

52
Q

ATP-ADP translocase is what kind of transporter

A

antiporter

53
Q

Inhibition of translocase leads to

A

the subsequent inhibition of cellular respiration

54
Q

about a quarter of the proton-motive force generated by the respiratory chain is consumed by

A

ATP-ADP translocase’s exchange process

55
Q

The regulation of cellular respiration is governed primarily by the need for

A

ATP

56
Q

The complete oxidation of glucose yields about ____ molecules of ATP

A

30

57
Q

glucose is completely oxidized to

A

CO2

58
Q

Regulation of cellular respiration

A
  • levels of ATP regulate respiration
  • electrons flow through ETC only when ADP phosphorylated to ATP
  • Regulation by ADP levels called respiratory control
59
Q

The regulation of the rate of oxidative phosphorylation by the ADP level is called

A

respiratory control or acceptor control

60
Q

electrons are transferred to O2 only if ADP is

A

concomitantly phosphorylated to ATP

61
Q

Regulation of ATP synthase

A
  • inhibitory factor I (IF1) -inhibits hydrolytic activity of ATP synthase
    - prevents the reverse reaction, i.e. ATP breakdown
  • is useful to prevent the hydrolysis of ATP when oxygen not available to make protein gradient
62
Q

Warburg effect

A
  • the switch form oxidative phosphorylation to aerobic glycolysis as the principle means for ATP synthesis
  • caused by the over-expression of IF1 (inhibitory factor 1), which is common in many types of cancers
63
Q

Some organisms can uncouple oxphos from ATP synthesis. Why?

A

Used to generate heat and maintain body temperature (important in hibernating animals)

64
Q

in animals the uncoupling of oxidative phosphorylation from ATP synthesis to generate heat is found in

A

brown adipose tissue (BAT)

65
Q

why is brown adipose tissue reddish brown

A

due to cytochromes in the numerous mitochondria and hemoglobin present in extensive blood supply

66
Q

Brown adipose tissue is rich in

A

mitochondria

67
Q

The inner mitochondrial membrane of brown adipose tissue mitochondria contain large amounts of

A

uncoupling protein (UCP-1) or thermogenin

68
Q

what is the function of uncoupling protein 1 (thermogenin)

A

Transfers protons form cytoplasm to matrix side without producing ATP, thus converting engr. to heat instead of ATP

69
Q

what are the two other uncoupling proteins

A

UCP-2 (found in a variety of tissues)
UCP-3 (found in skeletal muscle and brown fate)
-may play a role in homeostasis

70
Q

The family of uncoupling proteins may play a role in

A

homeostasis

71
Q

_____ inhibits ATP synthase by preventing the influx of protons by binding to the carboxylate group of the c subunits required for proton binding

A

Oligomycin (Antibiotic and anti fungal agent)

72
Q

Uncouples electron transport from ATP synthase

A

2,4-dinitrophenol (dissipates the proton gradient)

73
Q

____ and ____ inhibit ATP-ADP translocate thus inhibiting ATP export

A

Atractyloside and bongkrekic acid

74
Q

How does Oligomycin inhibit Oxidative phosphorylation

A

Inhibits ATP synthase by preventing the influx of protons through ATP synthase by bidding to the carboxylate group of the c subunits

75
Q

How does 2,4 dinitrophenol inhibit oxidative phosphorylation

A

uncouples electron transport from ATP synthase

In the presence of 2,4 dinitrophenol (DNP) electron transport from NADH to O2 proceeds in a normal fashion, but ATP is not formed by mitochondrial ATP synthase, because the proton-motive force across the inner mitochondrial membrane is continuously dissipated.

  • Leads to increase in oxygen consumption and release of Heat
76
Q

Inhibit electron transfer in NADH-Q oxidoreductase

A

Rotenone and Amytal

77
Q

Inhibits the electron flow form cytochrome bH in Q-cytochrome c oxidoreductase

A

Antimycin A

78
Q

Cyanide (CN-), Azide (N3-), and Carbon monoxide (CO) inhibit

A

Cytochrome c Oxidase

cyanide and Azide react with the ferric form of heme a3 and carbon monoxide inhibits the ferrous form

79
Q

what inhibits cytochrome c oxidase

A

Cyanide, Axide, and carbon monoxide

80
Q

Atractyloside and Bonkrekic inhibit

A

ATP export by inhibiting ATP-ADP translocase

Biochemistry Exam III material (13 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions