electron transport chain 4

Question 1

What is the name of complex 2?

Answer 1

Succinate dehydrogenase

Question 2

What is ‘special’ about succinate dehydrogenase?

Answer 2

No protons are translated across the inner mitochondrial membrane

Question 3

How is succinate dehydrogenase directly linked to the citric acid cycle?

Answer 3

Oxidises succinate to fumarate, which converts FADH2 into FAD

Question 4

How are the electron pairs transferred through complex 2?

Answer 4

Series of Fe-S clusters and cytochrome b560

Question 5

What does FAD stand for?

Answer 5

Flavin adenine dinucleotide

Question 6

What is the name of complex 3?

Answer 6

Ubiquinone - cytochrome c Oxidoreductase

Question 7

What are the two binding sites in complex 3?

Answer 7

Qp and QN

Question 8

How are the electrons transferred through complex 3?

Answer 8

several prosthetic groups that function as electron carriers (Fe–S cluster and hemes bL, bH, and c1)

Question 9

How does the oxidation of QH2 occur?

Answer 9

to produce Q and two molecules of reduced cytochrome c (Cytc) requires the Q cycle .

Question 10

How many cytochrome C molecules are required after complex 3?

Answer 10

2 molecules needed

Question 11

How are cyt c groups linked to haem groups?

Answer 11

Covalently linked to protein through thiol groups from cis residues

Question 12

What are the 3 types of harm group in the ETC?

Answer 12

a, b and c

Question 13

Why must Coq and CyC make two trips?

Answer 13

transport 1e- at a time, so must make two trips to transfer 2e- from NADH or FADH2 to ½ O2 to form H2O

Question 14

What is the name of complex 4?

Answer 14

Cytochrome c Oxidase

Question 15

How many Hydrogens are used in regards to the complex 4?

Answer 15

4

Question 16

How many protons are translated through complex 4?

Answer 16

2

Question 17

what are the use of the other 2 hydrogens in the complex 4?

Answer 17

used to form water

Question 18

How many hydrogens are pmed through starting with CoQ and FADH2 molecules?

Answer 18

6

Question 19

What do the F1 and Fo components involve in ATP synthase in bacteria and yeast?

Answer 19

F1 = catalytic activity 
Fo = H plus channel

Question 20

What is the δ subunit in yeast homologous to in bacteria?

Answer 20

homologous to the bacterial ε subunit

Question 21

What are the 3 parts of ATP synthase made up of?

Answer 21

• stator
• Rotor
• Headpiece

Question 22

What is the strator subunit made up of?

Answer 22

• half-channels for H+ to enter and exit FO, plus stabilizing arm (b, d, h and OSCP)

Question 23

What is the headpiece subunit made up of?

Answer 23

• : hexameric a3b3 unit responsible for ATP synthesis

Question 24

What is the rotor subunit made up of?

Answer 24

c + g + d + e rotate as H+ enter and exit c-ring

Question 25

What is the role of the rotor?

Answer 25

responsible for translating proton-motive force into protein conformational changes in the headpiece

Question 26

How do protons pass through ATP synthase?

Answer 26

The protons, come through the a subunit. There are two channels , each channel gets the proton part way through a membrane The protons get so far across in one a channel, and then they go on round the rotary part of c subunit and then reaches the other channel in the a subunit and gets across the membrane

Question 27

Which part of ATP synthase is catalytic?

Answer 27

Beta subunit

Question 28

What is the first basic principle for the binding mechanism of ATP synthesis?

Answer 28

Gamma directly contacts all three b subunits, but each interaction is distinct, giving rise to 3 different b conformations

Question 29

What is the second basic principle for the binding mechanism of ATP synthase?

Answer 29

ATP binding affinities of the 3 b subunits are T, L and O (tight, loose and open) T: ATP bound L: ADP and Pi bound O: ATP is released

Question 30

What is the third basic principle for the binding mechanism of ATP synthase?

Answer 30

H+ flow through FO causes rotation of g subunit counterclockwise during ATP synthesis (looking at F1 from matrix side). With each 120° rotation, b subunits switch conformation sequentially L T O L

Question 31

Who were given the prize for the study of structure of ATP synthase

Answer 31

John E. Walker and Paul D. Boyer

Question 32

What was the experimental evidence that proved how ATP synthase rotates?

Answer 32

Experimental proof that ATP synthase rotates, and that it rotates in reverse under conditions that favour ATP hydrolysis rather than ATP synthesis

Question 33

how was the experiment done to prove how ATP synthase rotates?

Answer 33

Took the catalytic part and attached the long filament to the gamma filament that fluoreses

Question 34

Who came up with the ATP synthase experiment?

Answer 34

Yoshida and Kinosita

Question 35

How does the experiment work in which theF1 component as a nanomotor driving ATP synthesis in absence of electrochemical proton gradient

Answer 35

. a. In place of the actin filament , a magnetic bead was attached to the γ subunit via streptavidin. b. Six electromagnets in a circular arrangement around the experimental chamber were used to force rotation of the magnetic bead to drive ATP synthesis in the absence of a proton gradient.

Question 36

How does H+ movement cause rotation of gamma subunit?

Answer 36

Two channel model

Question 37

How does H+ movement cause rotation of gamma subunit?

Answer 37

H+ neutralizes D59 allowing c subunit to rotate 36° into hydrophobic membrane This rotation allows D59 in a different c subunit to access the second half-channel in the a subunit and exit the channel because of the low H+ concentration on matrix side Carousel analogy: each H+ must ride once around the c ring carousel to exit into matrix