Oxidative Phosphorylation

Question 1

What is oxidative phosphorylation?

Answer 1

energy production in the cell in the form of ATP

Question 2

First, the energy production starts with _____________________.

Answer 2

the flow of electrons from NADH and FADH2 through the electron transport chain.

Question 3

Second, the electron flow generates the flow of __________________ from the matrix, across the _________ _________ _________, to the ________________ _______________.

Answer 3

flow of hydrogen ions (H+) from the mitochondrial matrix, across the inner mitochondrial membrane, to the intermembrane space.

Question 4

Lastly, the hydrogen ions (H+) flow back into the _____________ through a ________ __________, which drives the production of _________.

Answer 4

matrix, membrane protein, ATP.

Question 5

True or False: The mitochondrion only has an inner membrane

Answer 5

False, the mitochondrion has both an outer and inner membrane.

Question 6

describe the outer membrane of the mitochondrion.

Answer 6

a bilayer that has porin proteins that permit ions and molecules to cross the intermembrane space.

Question 7

Where are porin proteins located and what is their function?

Answer 7

Porin proteins are located in the outer membrane of the mitochondrion and their function is to permit ions and molecules to cross the intermembrane space

Question 8

Describe the intermembrane space.

Answer 8

The solution between the outer and inner membranes.

Question 9

Describe the inner membrane.

Answer 9

A highly selective bilayer permitting only select ions and molecules to cross.

Question 10

Why is the selectivity within inner membrane for certain ions and molecules so important?

Answer 10

The selectivity is crucial for maintaining specific concentrations of H+, ATP, and other species in the mitochondrial matrix.

Question 11

Where are the 4 complexes of the electron transport chain located in the mitochondrion?

Answer 11

Inner membrane

Question 12

How many protein complexes are in the electron transport chain?

Answer 12

4

Question 13

What is the electron transport chain responsible for?

Answer 13

accepting electrons from coenzymes for ATP formation

Question 14

Name 3 coenzymes involved in ATP formation

Answer 14

NADH, FADH2, and coenzyme Q (coQ)

Question 15

Describe the Matrix.

Answer 15

The innermost space of mitochondrion.

Question 16

Where in the mitochondrion does the Citric Acid Cycle occur, as well as portions of Fatty Acid Oxidation and Urea cycle?

Answer 16

Mitochondrial Matrix (matrix).

Question 17

Which cycle are coenzymes NADH and FADH2 produced in ?

Answer 17

Citric Acid Cycle

Question 18

Once NADH and FADH2 are produced in the CAC, they are ready to enter the ___________.

Answer 18

electron transport chain

Question 19

NADH and FADH2 enter the electron transport chain so that ________________________.

Answer 19

the donation of electrons and hydrogen ions is rapid and efficient.

Question 20

What is the net reaction of electron transport chain ? (hint: it’s a one way reaction equation)

Answer 20

4H+ +4e- + O2 ——> 2H20
(4 hydrogen ions from matrix solution)

(4 electrons from NADH and FADH2)

(Oxygen breathed in)

(electron flow to Oxygen molecule (O2) and O2 reacts with 4H+ to form 2 H2O molecules).

Question 21

What is Complex I in the the ETC?

Answer 21

Complex I is a large, integral protein.

Question 22

How many polypeptide subunits and coenzymes does Complex I have? Name 2 coenzymes from Complex I.

Answer 22

Complex I contains 40 polypeptide subunits, and several coenzymes, including flavin and coenzyme Q (CoQ).

Question 23

In Complex I, Coenzyme Q oxidizes which coenzyme to produce NAD+ ?

Answer 23

NADH

Question 24

Complex I oxidizes _____ to form _____ and takes up an ____ ion from the matrix in the following reaction: _____________________.

Answer 24

NADH, NAD, H+

NADH + (H+) + CoQ —-> (NAD+)+ CoQH2

Question 25

What is the function of CoQH2 in complexes I and II?

Answer 25

shuttles electrons and hydrogens to complex III

Question 26

NADH + (H+) + CoQ ----> (NAD+)+ CoQH2 In result of this reaction in Complex I, __ hydrogen ions are pumped across from the _______________ to the _______________.

Answer 26

4 ,mitochondrial matrix, intermembrane space.

Question 27

In Complex I, what is the result of Hydrogen ions pumping ? what does it further result in?

Answer 27

The pumping results in a net exit of Hydrogen ions from the matrix, which further results in a deficiency of Hydrogen ions in the mitochondrial matrix and slight excess in the intermembrane space.

Question 28

What will pumped Hydrogen ions be used for as it relates to the last step of oxidative phosphorylation?

Answer 28

The pumped hydrogen ions will be used to make ATP

Question 29

Complex II also transfers electrons and hydrogens to CoQ but from _________. How is complex II different from complex I?

Answer 29

transfers electrons and hydrogens to CoQ but from FADH2 smaller and less complex.

Question 30

Remember, the source of coenzyme FADH2 is the oxidation of ___________ in the ___________.

Answer 30

succinate, citric acid cycle.

Question 31

What is the reaction equation for Complex II?

Answer 31

FADH2 + CoQ ---> FAD + CoQH2 FADH2 oxidized into FAD CoQ = coenzyme Q FAD = result of FADH2 being oxidized CoQH2 = shuttles e- and h+ to complex III

Question 32

In this complex, there is not enough energy to pump Hydrogen(H+) ions across the membrane, nor is there a pore/channel for this to occur.

Answer 32

Complex II.

Question 33

Complex III accepts ______ from CoQH2 produced at complexes I & II.

Answer 33

electrons

Question 34

After Complex III accepts electrons from CoQH2 produced at complexes I and II, where are the electrons shuttled to?

Answer 34

Complex III shuttles the electrons to cytochrome C.

Question 35

Each cytochrome C accepts how many electrons? Thus, how cytochrome C proteins are needed?

Answer 35

1 electron per cytochrome C. 4 cytochrome C proteins.

Question 36

Complex III is an integral protein that contains ______ polypeptide subunits and has several species that accept electrons.

Answer 36

11 polypeptide subunits.

Question 37

True or False: Complex III has 2 channels to pump H+ ions from the matrix to the intermemebrane space.

Answer 37

False, Complex III has a channel to pump 2 H+ ions from the matrix to the intermembrane space.

Question 38

In which 2 complexes are 4 H+ ions pumped from the matrix to the intermembrane space? ' In which complex are 2 H+ ions pumped from the matrix to the intermembrane space?

Answer 38

Complex I and IV. Complex III.

Question 39

In Complex IV, the 4 molecules of cytochrome C each deliver ___________ here, which is known as __________________.

Answer 39

1 electron, cytochrome oxidase.

Question 40

The ___ electrons flow through Complex IV to an _____ molecule that reacts with __ hydrogen ions to yield ______ molecules.

Answer 40

4, Oxygen, 4, 2 H2O

Question 41

What is the reaction equation for complex IV?

Answer 41

O2 + 4e- + 4(H+) ----> 2H2O

Question 42

Where does the energy to pump the 4H+ ions come from?

Answer 42

The pumping of the H+ions comes from the energy in breaking chemical bonds.

Question 43

In Complex IV, the additional H+ translocation continues to build up the _______________, which is higher in the intermembrane space and lower in the matrix.

Answer 43

H+ concentration

Question 44

Is H+ concentration higher in the intermembrane space or the matrix?

Answer 44

Intermembrane space.

Question 45

The electrons flow through the 4 complexes of the _____________ to convert _____ into _______with H+ pumping.

Answer 45

electron transport chain, O2, H2O

Question 46

Which enzyme is in in complex I?

Answer 46

NADH dehydrogenase

Question 47

Which enzyme is in complex II?

Answer 47

Succinate dehydrogenase

Question 48

Which is in complex III? a. Cytochrome c- Oxidase b. Cytochrome b-c1

Answer 48

b.

Question 49

Which is in complex IV? A. CYTOCHROME C OXIDASE B. CYTOCHROME B-C1

Answer 49

a.

Question 50

Complexes within the electron transport chain accept electrons from what kinds of enzymes?

Answer 50

coenzymes

Question 51

Where does oxidative phosphorylation occur in the mitochondrion?

Answer 51

matrix

Question 52

True or False coenzyme Q is hydrophobic so it would be on the inside of a membrane.

Answer 52

true

Question 53

cytochrome c, a small protein, is hydrophobic or hydrophilic?

Answer 53

hydrophobic

Question 54

cytochrome c contains alpha helices and heme rings, ; heme rings help carry __________ and _________.

Answer 54

carry protons and electrons

Question 55

hydrogen ions (protons) are pumped in which direction of the potential gradient?

Answer 55

upward

Question 56

In phase 3, protons flow back down the potential gradient through the ATP enzyme called _________.

Answer 56

ATP synthase

Question 57

As protons move through the ATP synthase, ATP synthase turns and physically converts ADP to ___.

Answer 57

ATP