Exam 3: ETC

Question 1

Where does the ETC happen

Answer 1

in mitochondrial inner membrane

Question 2

What kind of complexes are in the ETC

Answer 2

transmembranes, complex 2 not quite across full membrane

Question 3

Describe how electrons travel through complex 1

Answer 3

FMN picks up H+ from NADH and transfers it to iron sulfur clusters then to ubiquinone

Question 4

What is ubiquinone

Answer 4

an organic molecule with a long HC tail that can take an e- from complex 1 and or 2 to complex 3

Question 5

What other name does complex 3 have

Answer 5

cytochrome BC complex

Question 6

What is the Q cycle

Answer 6

process of moving through complex 3 to cytochrome C

Question 7

What does UQ do after the e passes through complex 3

Answer 7

takes e- and transfers it to cytochrome C

Question 8

How many e- are transferred from cytochrome C to complex 4

Answer 8

4e-

Question 9

What is the respirazome / supramolecular complex

Answer 9

complex 1-3 to cytochrome C, complex is close together to help reduce RO species

Question 10

How does antimycin allosterically inhibit the ETC

Answer 10

blocks NADH and FADH from using O2 in complex 3

Question 11

How is O2 consumption affected when complex 1 is allosterically inhibited

Answer 11

NADH no O2 consumption

still allows some O2 consumption from FADH2

Question 12

What is the process happening after ETC in the ATP synthase called

Answer 12

oxidative phosphorylation

Question 13

What are the tallies of H+ for ETC from NADH and FADH2

Answer 13

NADH: complex 1-3 (4H+ each), complex 4 (2H+), total 10 H+
FADH2: complex 3: 4H+
complex 4: 2 H+, total 6H+

Question 14

Name 2 uncouplers that can disrupt the ETC

Answer 14

dinitrophenol: sits in membrane can pick up H+
gramicidin: transmembrane protein that forms pure form of H+ (deadly)

Question 15

What are the 2 subunits of ATP synthase

Answer 15

Fo (rotor) and F1 (enzyme activity)

Question 16

What subunits does Fo have

Answer 16

1a (stationary, attached to c-ring), has 2 half channels

1b: attaches the Fo to F1

Question 17

What does the F1 unit do, what is it made of

Answer 17

catalyzes rxn, made of 3 alpha and 3 beta subunits forming hexomer together

Question 18

What does the stalk do and what is it made of

Answer 18

anchor, E (epson) and gamma subunits form stalk, sigma subunit is achor

Question 19

Where does H+ enter the ATP synthase

Answer 19

half channel in subunit 1A from innermembrane space goes to C subunit

Question 20

Explain the steps after H+ enters ATP synthase

Answer 20

C subunit gets H+ binds to Asp, causes shifting of C unit, Ring A unit is stationary. shift causes conformation change in epson and gamma subunits of FO, causes conformation shift of alpha beta subunits in F1, this catalyzes ADP+ Pi –>ATP

Question 21

Where do the 2 half channels of subunit 1a go

Answer 21

1 open to matrix

1 open to innermembrane space

Question 22

Where do the 3 conformation changes LTO happen

Answer 22

beta subunit of F1

Question 23

Explain what L, T and O mean

Answer 23

L: loose, inactive high affinity for ADP+Pi
T: tight, active, high affinity for ADP+Pi
O: open, inactive, low affinity for ADP, Pi and ATP

Question 24

What does it mean when the P/O ration is high

Answer 24

high: ETC and ATP synthase are making lots of ATP
low: making less ATP but pumping lots of H+

Question 25

What is the P/O ratio

Answer 25

moles of Pi consumed (ATP synthase)/ O2 reduced to H2O (complex 4)

Question 26

What risk is there to having a low P/O ratio?

Answer 26

can cause increase in O2 reactive species

Question 27

What are the ADP and ATP translocators

Answer 27

allow ATP out and ADP in, an antiport, negatively regulated by ADP in

Question 28

What is phosphate translocase

Answer 28

HPO4 and H+ symport

Question 29

How many H+ does ATP synthase need to produce 1 ATP

Answer 29

3H+

Question 30

The ultimate e- acceptor if the mitochondrial electron transport system is

Answer 30

O2

Question 31

In complex 3 electrons are transferred from UQH2 to

Answer 31

cytochrome C

Question 32

The final product of oxidative phosphorylation is

Answer 32

ATP

Question 33

The reducing power generated in the cytoplasm can be transferred to the mitochondrion by which processes?

Answer 33

glycerol phosphate and malate asp shuttle

Question 34

Which of the following is not a step of ATP synthesizing process

Answer 34

The O conformation binds to ADP and pi

Question 35

How many protons are needed to drive the phosphorylation of ADP by the mitochondrial ATP synthase

Answer 35

4H+

Question 36

What is not a component of ETC and not an e- carrier

Answer 36

coenzyme A

Question 37

In the ATP synthase, the Fo factor

Answer 37

has 3 types of subunits and is a transmembrane proton channel