Koc - Ox Phos Flashcards

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1
Q

What are electron carriers for Complex I and Complex II?

A

FMN , FAD

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2
Q

What is the only complex in OxPhos not mitochondrial coded?

A

Complex II

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3
Q

Cytochromes

A

One elctron carriers

Iron coordinating rings

Mitochondrial coded

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4
Q

Iron-Sulfur Clusters

A

Non mobile electron intermediate carriers within the Complexes

sort of like buckets for the fire brigade to pass water

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5
Q

Ubiquinone or “CoenzymeQ” , “CoQ10”

A

Mobile electron carrier

Freely diffusible within the lipid bilayer

Complex II - Complex III

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6
Q

Rieske Iron Sulfure Protein

A

Non-heme iron protein in complex III

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7
Q

Complex I

A

NADH:Ubiquinone Oxidoreductase

Transfer two electrons from NADH to Ubiquinone

Four protons sent to intermembrane space

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8
Q

Complex II

A

Succinate Dehydrogenase

Same enzyme form Kreb’s cycle (Succinate - Fumarate)

Electrons from FADH2,, sent to Ubiquinone

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9
Q

Complex III

A

Ubquinone:Cytochrome C Oxidoreductase

QH2 gives two electrons to Cytochrom C

Four Protons pumped

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10
Q

When does Cytochrome begin acting as mobile transport in ETC?

A

After III, Cytochrome C

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11
Q

Cytochrome C

A

Mobile electron carrier

Moves through intermembrane space

Heme protein

Carry 1 electron

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12
Q

Complex IV

A

Cytochrome Oxidase

O2 reduced to 2H2O

Four protons transported to intermembrane space

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13
Q

Protons per molecule NADH?

What complexes does this pass flow through?

A

10 H+

Complex I - Complex IV

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14
Q

Protones per molecule FADH2

What complexes does this pass through?

A

6 protons

Complex II - Complex IV

(skips complex I)

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15
Q

What is there “3-5” ATP made from the NADH from glycolysis?

A

The NADH must be transported from the cytoplasm, and one of these methods inserts it at Complex II, so less protons are pumped at the end.

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16
Q

Malate-Aspartate Shuttle

A

Full complex chain

2.5 ATP / NADPH

(2x NADPH from glycolysis, 5 ATP total)

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17
Q

Glycerol 3 Phosphate Shuttle

A

Enters at complex II

1.5 ATP / FADH2

3 ATP total

18
Q

Where is the Malate-Aspartate Shuttle predominantly found?

A

Liver, Kidney, Hear

No energy lost

19
Q

What systems use the Glycerol 3-Phosphate Shuttle?

A

Skeletal Muscle and Brain

“Where is glycolysis prevalent?”

20
Q

Comple I Inhibitors

A

Amytal, Rotenone

21
Q

Complex III Inhibitors

A

Antimycin A

22
Q

Complex IV Inhibitors

A

Cyanide, Carbon Monoxide, Hydrogen Sulfide, Sodium Azide

23
Q

ATP Synthase Inhibitor

A

Oligomycin

24
Q

Uncoupling Agents

Example?

A

Break proton gradient

Dinitrophenol

Aspirin (high doses)

25
Q

Addition of Cyanide to mitochondria?

ATP and O2 effect?

A

Complex IV inhibited

O2 not consumed

ATP not generated

26
Q

Addition of DNP to mitochondria?

Effect on ATP and O2?

A

Uncoupling agens–proton gradient broke

O2 - Still consumed, Complex IV can still run

ATP - Not produced, no protons to spin ATP Synthase

27
Q

ATP Synthase

F1 / Fo?

Protons/ATP?

A

F1: Makes ADP in Matrix

Fo: Transports protons, spins

4 Protons / ATP

28
Q

ATP Synthase Inhibitory Protein (IF1)

A

Prevents ATP hydrolysis during Ischemia

Bridges two synthase molecules, to lock them from spinning

Active at lower pH, low oxygen

29
Q

How is ADP/ATP transported between the mitochondrial membranes?

How is phosphate moved?

A

Adenine Nucleotide Translocase Antiporter

Relies on movement of protons going down their gradient

- -

Phosphate enters via symport with hydrogen

30
Q

Non Shivering Thermogenesis

Brown Fat

A

Uncoupling proteins (UCP1) or thermogene expressed in BAT breaks proton gradient, causes heat release

  • -

Brown fat contains more mitochondria, activated by cold and exercise

31
Q

What is source of many ROS?

A

CoQ is “leaky” and can be partially reduced

32
Q

What does mass leakage of Cytochrome C initiate?

A

Apoptosis

33
Q

What are the prosthetic groups and co-substrates required by PDH?

A

TPP (E1) - Transfer alkyl group

Lipoate (E2) - Oxidation and transfer of an acyl group

CoA (E2) - Co-substrate, Acetyl acceptor

FAD (E3) - Oxidation of lipoate

NAD (E3) - Co-substrate, oxidation of FADH2

34
Q

What is primary mchanism of PDH regulation?

A

Phosphorylation

Activate=Phosphatase

Inactivate=Kinase: NADH, Acetyl-CoA (end products)

35
Q

What are the irreversible (favorable) steps of the Citric Acid Cycle?

A
  1. Citrate Synthase
  2. Isocitrate Dehydrogenase
  3. a-Ketoglutarate Dehydrogenase
36
Q

What is the origin of Carbon atoms lost in the Citric Acid Cycle?

A

OAA

37
Q

How many electrons can CoQ carry?

A

2

38
Q

What is purpose of IF1?

A

Prevents ATP Synthase from working in reverse when proton concentrations are flipped

39
Q

How many protons are required per ATP?

A

4 (3+1)

3x ATP Synthase

1x for Pi Symport

40
Q
A