Electron Transport Chain (ETC) (Deevska)

Question 1

Can you have oxidation without a reduction reaction?

Answer 1

No they go hand in hand together.

Question 2

What is the equation in the ETC? What is the electron donor and acceptor? What is being oxidized and what is being reduced?? What is the Energy?

Answer 2

Glucose (C6H12O6) (DONOR)
6O2 (Electron acceptor)
6CO2 (Oxidized)
6H20 (Reduced) 
Energy in form of 38 ATP

Question 3

With NAD+ and NADH RedOx reactions which is being oxidized and which is being reduced?

Answer 3

NAD+ is oxidized

NADH is reduced

Question 4

With FAD and FADH2 which is oxidized and which is reduced?

Answer 4

FAD is oxidized

FADH2 is reduced

Question 5

What organelles have a double membrane?

Answer 5

Mitochondria and chloroplasts

Question 6

TCA cycle enzymes, Fatty acide oxidation enzymes, mtDNA, mtRNA, and Mitochondrial ribosomes reside in the __________ of the mitochondria.

Answer 6

Matrix

Question 7

True/false: Inner membrane of the mitochondria is permeable to most small ions, small and large molecules

Answer 7

False, impermeable

Question 8

True/False: Outer membrane is permeable to most ions and small molecules (via small channels, porins)

Answer 8

True

Question 9

NADH + H+ to NAD+ is done via __________________; (complex 1 of ETC)

Answer 9

NADH dehydrogenase (FMN)

Question 10

Succinate to Fumarate is done via ________________; (complex 2 of ETC)

Answer 10

Succinate dehydrogenase (FAD)

Question 11

COmplex 1 and 2 combine to make ____________ which is the only nonprotein carrier in the ETC.

Answer 11

Coenzyme Q (CoQ)- long hydrophobic tail, helps move it around within membrane

Question 12

__________ is the only TCA enzyme embedded in the mitochondrial membrane.

Answer 12

Succinate Dehydrogenase (FAD) contains iron-sulphur center…

Question 13

Complex III is made up of ______ and _______ which are cytochrome proteins…

Answer 13

Cyt b and Cyt c1

Question 14

Each Cyt contain a _____ group (porphyrin ring + iron)

Answer 14

heme

Question 15

COmplex IV consists of _______ and _______ which are cytochrome proteins.

Answer 15

Cyt a and Cyt a3 cytochrome proteins

Question 16

Complex IV contains this element which is required for transfer of electrons.

Answer 16

Copper

Question 17

What is the reason why electrons flow along the ETC? Hence, what is the relative strength of the complexes…

Answer 17

NADH is a strong electron donor, Cytochrome C1 (complex III) is the weakest acceptor, then CuB (complex IV) and then Oxygen is the strongest electron acceptor.

Question 18

What is Complex V and where does it get its energy?

Answer 18

The flow of protons into the intermembrane space decreases the pH and makes an elctrochemical gradient… proton gradient that drives the ATP Synthase to make ATP.

Question 19

What are the two domains of the ATP-synthase and where/what do they do?

Answer 19

Domain F0 spans the inner mitochondrial membrane and contains the active site and synthesizes ATP.
Domain F1 is outside the mitochondrial matrix and contains the catalytic activity.

Question 20

How do protons flow through the ATP- synthase to make it function?

Answer 20

Protons flow through F0 domain driven by gradient turning F1 domain. Rotation of F1 domain causes conformational change allowing it to bind ADP+ Pi and phosphorylate ADP to ATP and release ATP for energy.

Question 21

Explain mechanisms of how blocking the flow of electrons in any reaction can effect all of the ETC.

Answer 21

1. Prevent flow of e- through ETC
2. Result in too much energy in form of NADH
3. this inhibits TCA cycle causes anaerobic pyruvate to produce lactate.
4. Blood lactate levels go up
5. Aerobic tissues like the heart and brain will be severely affected.

Question 22

Name 2 inhibitors of Complex 1. and what they do.

Answer 22

Amytal- barbituate

Rotenone- insecticide, piscicide and pesticide

Question 23

____________ is an inhibitor of COmplex III and used as a piscicide.

Answer 23

Antimycin A

Question 24

___________ is an inhibitor of Complex IV and may be seen when people are exposed to house fires or industrial fires.

Answer 24

Cyanide (CN-) irreversibly binds to Fe3+ in Cyt C-oxidase

Question 25

____________ is an inhibitor of Complex IV and is associated with tight binding to hemoglobin.

Answer 25

Carbon Monoxide (CO)

Question 26

_________ is an inhibitor of Complex IV and is used in airbags, explosives, and antimicrobial preservative.

Answer 26

Sodium Azide (NaN3) binds similarly to Cyanide, to Fe3+ of iron in cytochromes.

Question 27

___________ is an inhibitor of Complex V; it binds to the F0 domain and closes the proton channel which shuts down ATP synthesis, used as a tool to study ETC in the lab.

Answer 27

Oligomycin

Question 28

__________ is the allowing of protons to flow back through the membrane.

Answer 28

Uncoupling

Question 29

Uncoupling happens naturally by _________, localized in the inner mitochondrial membrane.

Answer 29

Uncoupling proteins (UCP's) which create a PROTON LEAK without capturing energy as ATP, and screws up the proton gradient and the whole process falls apart.

Question 30

Compounds that increase the permeability of the inner mitochondrial membrane to H+.

Answer 30

Synthetic Uncouplers

Question 31

Free energy released as heat is called

Answer 31

Nonshivering thermogenesis

Question 32

UCP1 is found in

Answer 32

Brown adipose tissue of mammals, including humans... newborns have hella brown fat.

Question 33

This was used as a weight loss drug in the 1930's but was banned because it was easy to overdose and caused a severe hyperthermia.

Answer 33

2,4- dinitrophenol

Question 34

Compounds containing ___________ acid will also cause uncoupling, including aspirin.

Answer 34

salicylic acid

Question 35

Incomplete reduction of oxygen to water causes production of __________.

Answer 35

Reactive Oxygen Species (ROS) - Superoxide (O2-) - Hydrogen peroxide (H2O2) - Hydroxyl radicals (OH)

Question 36

What 4 diseases can result from mutations in mtDNA or nuclear DNA?

Answer 36

1. (LHON) Leber Hereditary Optic Neuropathy 2. (MERRF) Myoclonic Epilepsy with Ragged Red Fibers 3. (MELAS) Mitochondrial Encephalomyopathy, lactic acidosis, and stroke like episodes 4. Leigh syndrome (subacute necrotizing encephalomyopathy)

Question 37

mtDNA encodes ____ of _____ proteins required for oxidative phosphorylation.

Answer 37

13 of 120

Question 38

mtDNA has a high mutation rate compared to nuclear DNA because of the constant exposure to ____.

Answer 38

ROS reactive oxygen species

Question 39

What can be severely affected by mutations in the mtDNA because of oxidative defects in oxidative phosphorylation.

Answer 39

aerobic tissues such as Brain (neuropathies) and Muscle cells (myopathies)

Question 40

What is the name of programmed cell death and what is the mechanism of this.

Answer 40

Apoptosis- PORES in mitochondrial membrane= CYT C leaves= binds and makes CASPASES= PROTEINS that carry out APOPTOSIS

Question 41

What element can cause tiredness? How?

Answer 41

insufficient Iron levels may cause tiredness because of the effects it has on proteins in the ETC.