Lecture3-ETC AND OXIDATIVE PHOSPHORYLATION Flashcards

1
Q

Why do we need mitochondria?

A

1.ATP biosynthesis
2. Mediation of cell death by apoptosis
3. Heat production (thermogenesis)
4. Intermediary metabolism (e.g. TCA cycle, fatty acid metabolism)
5. Genetics (maternal inheritance)

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2
Q

What is the function of the ETC?

A

Produce ATP through respiratory chains that produce a proton gradient

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3
Q

Where is the ETC being taken place?

A

Mitochondria intermembrane space and inner mitochondrial membrane

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4
Q

What is the NET energy of ETC

A

9 from NADH, 2 more FADH2 and I from GTP per TCA cycle

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5
Q

Which complexes make ATP?

A

I, III, IV

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6
Q

Which complex does not go through the membrane nor produce ATP?

A

Complex II

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7
Q

What is used in Complex I to work?

A

NADH dehydrogenase
FMN
Fe-S centers

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8
Q

What is used in Complex III to work?

A

Cytochrome bc1 complex
2b-type heme centers
riseske Fe-S center
o-type heme (cyt c1)

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9
Q

What does Complex II use to work?

A

Succinate dehydrogenase
FAD (covalent)
Fe-S centers
b-type heme

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10
Q

What is used in complex IV to work?

A

Cytochrome aa3 complex
2 a-type hemes
Cu ions

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11
Q

Which complexes use Fe-S centers?

A

I,II,III

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12
Q

Which complexes use heme groups?

A

II,III,IV

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13
Q

Which complex uses Cu ions ?

A

IV

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14
Q

Which complex use NADH?

A

Complex I with NADH dehydrogenase

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15
Q

What complex uses FADH2?

A

Complex II with succinate dehydrogenase

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16
Q

What complex is the cytochrome b-c1 complex?

A

III

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17
Q

What complex is the cytochrome c oxidase?

A

IV

18
Q

Where do the electrons end?

A

Cyt c

19
Q

What is Q

A

Q acts as a mobile component of the respiratory chain that collects reducing equivalents from the more fixed flavoprotein complexes and passes them on to the cytochromes.

20
Q

Hydrogens get move from ____ to _____

A

matrix to intermembrane space

21
Q

What P/O ratio?

A

number of energy-rich phosphate groups formed as ATP per oxygen molecule reduced in mitochondria

22
Q

What is the p/o ratio go nadh?

A

3

23
Q

What is the p/o ratio of Succinate/Fadh2?

A

2

24
Q

What inhibits Complex I?

A

Rotenone= broad spectrum insecticide

25
Q

what inhibits complex III?

A

antimycin A = antibiotic

26
Q

What inhibits complex IV?

A

cyanide and carbon monoxide = poison

27
Q

Besides blocking the complexes, what can inhibit ETC?

A

Iron deficiency anemia – cytochromes and sulfur-iron complexes of oxidative phosphorylation

28
Q

Oxidation of substrates is coupled to what?

A

phosphorylation of ADP -> ATP -> O2 consumption

29
Q

Respiration can only proceed when_____

A

Respiration (consumption of oxygen) proceeds only when ADP is present

30
Q

What is chemiosmotic theory?

A

This hypothesis states that a proton-motive force is responsible for driving the synthesis of ATP

31
Q

What are the 4 tenets of Chemiosmotic theory?

A

-Inner mitochondrial membrane is impermeable to protons
-Protons are pumped vectorially across inner mitochondrial membrane
-Electron transport and ATP synthesis are tightly coupled
-Presence of an ATP synthase

32
Q

What part of the ATP synthase is within the matrix?

A

F1

33
Q

What part of the ATP synthase is within the inner mitochondrial membrane?

A

F0

34
Q

what is the purpose of ATP synthase?

A

to make ATP

35
Q

What is the major source for mitochondrial ROS production

A

Complex III

36
Q

Coenzyme Q makes what

A

unstable intermediates of the Q cycle (*Q -) can lead to superoxide (H2O2) formation

37
Q

What is the protection against ROS and harmful oxidative stress

A

Superoxide dismutase (SOD) and catalase

38
Q

Where do mitochondrial disease come from?

A

Maternal inheritance

39
Q

The ETC is a source of what (not good)

A

ROS as a side product or electron leakage

40
Q

What is the p/o ratio of Succinate/Fadh2?

A

2