M104 T2 L4 (biochem diagram info only, rest at the end)

Question 1

What is the overall outcome of the series of reactions in the electron transport chain?

Answer 1

to oxidise NADH to NAD+

Question 2

What is the equation for the oxidation of NADH?

Answer 2

NADH + H+ + 1/2 O2 = NAD+ + H2O

Question 3

What is the energy released by the oxidation of NADH used for?

Answer 3

it’s used to produce ATP by the tight coupling of these reactions

Question 4

What are the four component proteins of the electron transport chain?

Answer 4

Complex I, II, III and IV (1 - 4)

Question 5

What are the soluble proteins that link the four component proteins of the electron transport chain?

Answer 5

coenzyme Q

cytochrome C

Question 6

What is coenzyme Q otherwise known as?

Answer 6

Ubiquinone

Question 7

What is the function of the e- transport chain?

Answer 7

to accept electrons from NADH or from FADH2 and use the energy to move or pump protons into the intermembrane space

Question 8

Where is Complex 1 located?

Answer 8

embedded in the inner mitochondrial membrane

Question 9

What happens to FMN in Complex 1?

Answer 9

it is reduced to FMNH2 by accepting electrons

Question 10

What happens once FMNH2 has been produced?

Answer 10

the electrons are subsequently transferred to a whole series of these iron-sulphur clusters

Question 11

What is the role of iron-sulphur clusters in Complex 1?

Answer 11

to accept and then donate electrons to coenzyme Q

Question 12

What is the overall equation that is catalysed by NADH dehydrogenase?

Answer 12

NADH + H+ + Q = NAD+ + QH2

Question 13

What type of structures is Complex 1?

Answer 13

an enzyme

a proton pump

Question 14

Why is Complex 1 a proton pump?

Answer 14

bc it moves protons from the matrix into the intramitochondrial space

Question 15

What reaction does Complex 2 catalyse?

Answer 15

it catalyses this conversion of succinate to fumarate

produces FAD, a reduced FADH2

Question 16

How is FAD in Complex 2 reduced to FADH2?

Answer 16

using electrons gained from the conversion of succinate to fumarate in the TCA cycle

Question 17

What happens to FADH2 when it is produced in Complex 2?

Answer 17

it is re-oxidized by passing those electrons again onto ubiquinone

Question 18

What are the different sources / entry points of electrons entering the electron transport chain?

Answer 18

TCA cycle at Complex 1 via NADH
TCA cycle at Complex 2 via succinate dehydrogenase
the Glycerol-3-phosphates shuttle directly into ubiquinone
ETF:Q oxidoreductase

Question 19

What is the role of ETF:Q oxidoreductase?

Answer 19

to accept electrons from the FADH2 that is generated in the first step of beta oxidation of fatty acids

Question 20

What is different about the outcome of e-s entering the ETC via complex 2 or via ubiquinone directly?

Answer 20

they bypass Complex 1

so overall there are four fewer H+ ions pumped into the intramembrane space than if they entered through Complex 1

Question 21

From where does Complex 3 accept electrons?

Answer 21

reduced ubiquinone

Question 22

What happens to the electrons gained by Complex 3?

Answer 22

it passes them to Complex 4 via Cytochrome C

Question 23

Which complexes in the ETC are also proton pumps?

Answer 23

1, 3 and 4

Question 24

What is the equation that represents the reaction for the synthesis of ATP?

Answer 24

ADP3- + Pi2- + H+ —> ATP4- + H2O

Question 25

What are the three specific systems in the membrane?

Answer 25

``` transport ADP and iP into the matrix synthesise ATP (in the inner mitochondrial membrane) transports ATP into the cytosol ```

Question 26

What is the role of ANT?

Answer 26

an antiporter - it moves ADP3- into the matrix from the intramitochondrial membrane space simultaneously transports ATP out into the cytosol moves two in different directions

Question 27

Where is ANT located?

Answer 27

in the inner mitochondrial membrane

Question 28

Why is ANT used to move ATP and ADP rather than another structure?

Answer 28

bc it is favoured by the electrochemical gradient that has been generated by the proton pump

Question 29

What is the overall charge in the intermembrane space?

Answer 29

very positively charged due to the H+ ions being pumped from the matrix

Question 30

What is the electrochemical gradient like when ANT is used to move ATP and ADP?

Answer 30

the intermembrane space is very positive compared to the matrix so ADP with 3 negative charges being swapped for one with 4 negative charges is greatly favoured by this electrochemical gradient

Question 31

Why is atractyloside highly poisonous?

Answer 31

bc it prevents ATP production in cells by oxidative phosphorylation bc there is insufficient ADP in the matrix to be able to generate ATP there is insufficient ATP that that could be transported into the cytosol for use in keeping the cell viable

Question 32

What two processes is phosphate translocase involved in?

Answer 32

oxidative phosphorylation and ATP synthesis

Question 33

Why is phosphate translocase a symporter?

Answer 33

bc it transports both phosphate and hydrogen ions into the matrix - in the same direction

Question 34

Why is phosphate translocase used to move phosphate and H+ rather than another structure?

Answer 34

bc it is favoured by the transmembrane proton gradient

Question 35

What type of reaction is the oxidation of NADH?

Answer 35

a highly exergonic reaction | the reaction is exergonic enough to allow that pumping of H+ ions across the membrane

Question 36

What is the oxidation of NADH coupled to?

Answer 36

it's coupled to the movements of H+ ions across the inner membrane

Question 37

In the respiration equation, why are 6 co2s made?

Answer 37

bc it starts with a 6C compound and we progressively lose two molecules of CO2 per turn of the TCA cycle

Question 38

What is the final yield of ATPs per one molecule of glucose via the ETC?

Answer 38

either 30 or 32 molecules of ATP

Question 39

What is the total yield of ATPs per glucose calculation based on?

Answer 39

on the basis that 2.5 ATP produced per every 10 protons pumped from the matrix

Question 40

For every 2 e-s entering the respiratory chain at Complex I, how many protons are pumped across the membrane?

Answer 40

ten protons

Question 41

For e-s entering the respiratory chain at Complex 2, how many protons are pumped across the membrane?

Answer 41

six protons

Question 42

For e-s entering the respiratory chain at Complex 2, how many moles of ATP are yielded?

Answer 42

1.5 moles of ATP

Question 43

What is the final ATP yield of glycolysis?

Answer 43

2x ATPs

Question 44

Which method of ATP synthesis is more efficient, glycolysis or the ETC?

Answer 44

ETC - 30 or 32 ATPs | glycolysis - 2 ATPs

Question 45

What is special about UCP1?

Answer 45

it has a specific H+ channel through which the [H+] may be dissipated - E released as heat

Question 46

What is the role of DNP?

Answer 46

to cross membranes 'ferrying' H+ across | provides an alternative mean by which H+ ions can re-enter the matrix

Question 47

What does DNP do with its protons?

Answer 47

each DNP mlc collects a proton from the IMS and moves through the membrane with it, depositing it in the matrix repeats

Question 48

What are the names of the different complexes?

Answer 48

complex I: NADH dehydrogenase complex II: Succinate dehydrogenase complex III: Coenzyme Q - cytochrome c oxidoreductase complex IV: Cytochrome oxidase