Brainscape's Knowledge GenomeTM

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


See full index

BIO1332 - Biochemistry > Oxidative Phosphorylation: The Electron Transport Chain > Flashcards

Oxidative Phosphorylation: The Electron Transport Chain Flashcards

1
Q

Where does the reducing power/electrons go?

A

The two mitochondrial membranes are separated by the intermembrane compartment

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

What is oxidative phosphorylation?

A

Process in which ATP is formed as a result of the transfer of electrons from NADH or FADH2 to oxygen (O2) by a series of electron carriers

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

What is the electron transfer chain?

A

A specialised set of protein complexes and electron carriers

Where three protein complexes span the membrane, one is located on the matrix side only

Two highly mobile electron carriers shuttle electrons

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

What shuttles electrons in oxidative phosphorylation?

A

Two highly mobile electron carries

Q and cyt c

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

Does the electron transfer go up or down the free energy gradient?

A

Down

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

Fill in the gap:

Each complex/carrier in the chain has a …… free energy than the preceeding member.

A

lower

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

Do electrons flow spontaneously or on purpose along the electron transfer chain?

A

spontaneously

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

How do electrons generate ATP energy?

A
  1. Electron-motive force is converted into a proton motive force
  2. Proton motive force is converted into phosphoryl transfer potential
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

How many steps are there in the oxidative phosphorylation?

A

6

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

What is step 1?

A

Step 1: Complex I - NADH-Q reductase

  • 2 electrons from NADH (H+) are transferred to FMN
  • NADH is converted back to NAD+
  • FMNH2 transfers 2 electrons to sets of Fe-S clusters
  • 2 electrons are transferred to coenzyme Q reducing it to QH2
  • Process cause 4 H+ from matrix to move to inter membrane
  • H+ cannot diffuse back into matrix creating a proton gradient
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Describe NADH-Q reductase:

A
  • Enzyme consisting of 34 polypeptides
  • Structure determined by EM at 22A resolution
  • Membrane spanning part and long arm extended into matrix
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What prothetic groups are in NADH-Q reductase?

A
  • Flavin mononucleotide (FMN)

- Iron-sulphur clusters (Fe-S)

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

What is step 2?

A

Step 2: Complex II – Succinate dehydrogenase

  • FADH2 is oxidised and loses two electrons to coenzyme Q via Fe-S clusters
  • Does not pump H+ = less ATP from FADH2 compared to NADH
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What is Succinate dehydrogenase bound to?

A

the inner mitochondrial membrane

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

What is step 3?

A

Step 3: Coenzyme Q

Q can accept 2 electrons from either Complex I (NADH) or Complex II (FADH2) to become QH2 and transfers them to complex III

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

What is another name for Coenzyme Q?

A

ubiquinone

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

What is coenzyme Q?

A

Q is hydrophobic and diffuses rapidly within the inner mitochondrial membrane

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

What is step 4?

A

Step 4: Complex III – Q-cytochrome c oxidoreductase

  • Complex iii catalyses the transfer of four electrons from 2 QH2
  • For each 2 electrons transferred from QH2, two H+ pass into the intermembrane space and one is donated to Q from the matrix and the other is donated to CytC.
19
Q

What is complex III?

A

-Homo-dimer with 11 distinct polypeptide chains.

Contains heme prosthetic groups (Fe3+—> Fe2+)

20
Q

What are the 4 electrons which is catalysed for transfer by complex III?

A

Electron 1: CytC
Electron 2: Q
Electron 3: CytC
Electron 4: QH2

21
Q

what is step 5?

A

Step 5: Cytochrome c

-Carries one electron from Q-cytochrome c oxidoreductase to cytochrome c oxidase (IV)

22
Q

What is Cytochrome c?

A
  • present in all organisms
  • mitochondrial respiratory chains
  • has a highly conserved structure
  • Small soluble protein containing c-type heme
23
Q

What is step 6?

A

Step 6: Complex IV - Cytochrome c oxidase

  • For every NADH molecule that enters the chain, 2 x cyt c transfer 2 electrons to oxygen
  • Splitting of O2 to generate 2H20 requires 4 protons and 4 electrons
  • Requires 2 x NADH
  • Results in 4H+ translocated into inter membrane space
24
Q

What is complex IV?

A
  • 13 polypeptide chains
  • Two heme groups (Fea3+ and Fea32+)
  • Contains two copper ions (CuB1+,CuA2+)
  • Contains redux centres
25
Q

Overview of the oxidative phosphorylation:

A

Three of our complexes are proton pumps: using electrons to pump H+ into the intermembrane space

26
Q

How does oxidative phosphorylation create a proton gradient?

A
  • Protons pumped across this membrane as electron flow through respiratory chain
  • Generates a pH and electrical gradient
27
Q

What route muse protons go through to get back into the matrix?

A

Through ATP synthase

28
Q

What are oxidation and ATP synthesis coupled by?

A

Transmembrane proton movement

29
Q

What is Complex V - ATP synthase?

A

A complex of many subunits forming a head, stalk and a transmembrane pore

  • F1 catalytic subunit
  • F0 proton-conducting subunit
30
Q

What is the F1 catalytic subunit of Complex V - ATP synthase?

A
  • Extends into the matrix
  • Five types of polypeptide chains: α3, β3, γ, δ and ε
  • The majority of F1 consists of α3, β3 subunits
31
Q

What is F0 proton-conducting subunit f Complex V - ATP synthase?

A
  • Hydrophobic - spans the inner mitochondrial membrane
  • Contains the proton channel of the complex
  • This channel consists of 10 c subunits forming a pore and an a subunit
32
Q

Can ATP be formed without the flows of H+ through the ATP synthase complex?

A

Yes

33
Q

What is the problem of ATP be formed without the flows of H+ through the ATP synthase complex?

A

ATP does not leave the catalytic site of the enzyme unless H+ flow through the pore

34
Q

Fill in the gap:

H+ ….. the ATP

A

Releases

35
Q

What is the final outcome of metabolism?

A

1 NADH = 10 H+ translocated = 2.5 ATP
1 FADH2= 6 H+translocated = 1.5 ATP

Total yield = 30 to 32

36
Q

What are the inhibitors of oxidative phosphorylation?

A
  • Rotenone: Insecticide (made by plants)
  • Amytal: Barbiturate
  • Antimycin A: produced by Streptomyces
37
Q

What inhibitors out of Rotenone, Amytal and Antimycin A act between Complex I and Q?

A

Rotenone and Amytal

38
Q

What inhibitors out of Rotenone, Amytal and Antimycin A act between Complex Q and III?

A

Antimycin A

39
Q

What are the inhibitor for Cytochrome c?

A

Cyanide

Carbon monoxide

40
Q

What is are uncoupling proteins?

A

The tight coupling of electron transport and oxidative phosphorylation can be disrupted

These allow protons to flow back across the membrane without going through ATP synthase. ‘Proton leak’

41
Q

What do synthetic uncouples increase?

A

Permeability of the inner mitochondrial membrane to protons

42
Q

What else uses proton motive force?

A

Bacteria

43
Q

Where does bacterial electron transport chain take place?

A

Inner membrane

44
Q

What does the proton gradient drive?

A

Rotation of flagella basal body

BIO1332 - Biochemistry (19 decks)

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