Electron Transport Chain (ETC) (Deevska) Flashcards
Can you have oxidation without a reduction reaction?
No they go hand in hand together.
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?
Glucose (C6H12O6) (DONOR) 6O2 (Electron acceptor) 6CO2 (Oxidized) 6H20 (Reduced) Energy in form of 38 ATP
With NAD+ and NADH RedOx reactions which is being oxidized and which is being reduced?
NAD+ is oxidized
NADH is reduced
With FAD and FADH2 which is oxidized and which is reduced?
FAD is oxidized
FADH2 is reduced
What organelles have a double membrane?
Mitochondria and chloroplasts
TCA cycle enzymes, Fatty acide oxidation enzymes, mtDNA, mtRNA, and Mitochondrial ribosomes reside in the __________ of the mitochondria.
Matrix
True/false: Inner membrane of the mitochondria is permeable to most small ions, small and large molecules
False, impermeable
True/False: Outer membrane is permeable to most ions and small molecules (via small channels, porins)
True
NADH + H+ to NAD+ is done via __________________; (complex 1 of ETC)
NADH dehydrogenase (FMN)
Succinate to Fumarate is done via ________________; (complex 2 of ETC)
Succinate dehydrogenase (FAD)
COmplex 1 and 2 combine to make ____________ which is the only nonprotein carrier in the ETC.
Coenzyme Q (CoQ)- long hydrophobic tail, helps move it around within membrane
__________ is the only TCA enzyme embedded in the mitochondrial membrane.
Succinate Dehydrogenase (FAD) contains iron-sulphur center…
Complex III is made up of ______ and _______ which are cytochrome proteins…
Cyt b and Cyt c1
Each Cyt contain a _____ group (porphyrin ring + iron)
heme
COmplex IV consists of _______ and _______ which are cytochrome proteins.
Cyt a and Cyt a3 cytochrome proteins
Complex IV contains this element which is required for transfer of electrons.
Copper
What is the reason why electrons flow along the ETC? Hence, what is the relative strength of the complexes…
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.
What is Complex V and where does it get its energy?
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.
What are the two domains of the ATP-synthase and where/what do they do?
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.
How do protons flow through the ATP- synthase to make it function?
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.
Explain mechanisms of how blocking the flow of electrons in any reaction can effect all of the ETC.
- Prevent flow of e- through ETC
- Result in too much energy in form of NADH
- this inhibits TCA cycle causes anaerobic pyruvate to produce lactate.
- Blood lactate levels go up
- Aerobic tissues like the heart and brain will be severely affected.
Name 2 inhibitors of Complex 1. and what they do.
Amytal- barbituate
Rotenone- insecticide, piscicide and pesticide
____________ is an inhibitor of COmplex III and used as a piscicide.
Antimycin A
___________ is an inhibitor of Complex IV and may be seen when people are exposed to house fires or industrial fires.
Cyanide (CN-) irreversibly binds to Fe3+ in Cyt C-oxidase
____________ is an inhibitor of Complex IV and is associated with tight binding to hemoglobin.
Carbon Monoxide (CO)
_________ is an inhibitor of Complex IV and is used in airbags, explosives, and antimicrobial preservative.
Sodium Azide (NaN3) binds similarly to Cyanide, to Fe3+ of iron in cytochromes.
___________ 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.
Oligomycin
__________ is the allowing of protons to flow back through the membrane.
Uncoupling
Uncoupling happens naturally by _________, localized in the inner mitochondrial membrane.
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.
Compounds that increase the permeability of the inner mitochondrial membrane to H+.
Synthetic Uncouplers
Free energy released as heat is called
Nonshivering thermogenesis
UCP1 is found in
Brown adipose tissue of mammals, including humans… newborns have hella brown fat.
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.
2,4- dinitrophenol
Compounds containing ___________ acid will also cause uncoupling, including aspirin.
salicylic acid
Incomplete reduction of oxygen to water causes production of __________.
Reactive Oxygen Species (ROS)
- Superoxide (O2-)
- Hydrogen peroxide (H2O2)
- Hydroxyl radicals (OH)
What 4 diseases can result from mutations in mtDNA or nuclear DNA?
- (LHON) Leber Hereditary Optic Neuropathy
- (MERRF) Myoclonic Epilepsy with Ragged Red Fibers
- (MELAS) Mitochondrial Encephalomyopathy, lactic acidosis, and stroke like episodes
- Leigh syndrome (subacute necrotizing encephalomyopathy)
mtDNA encodes ____ of _____ proteins required for oxidative phosphorylation.
13 of 120
mtDNA has a high mutation rate compared to nuclear DNA because of the constant exposure to ____.
ROS reactive oxygen species
What can be severely affected by mutations in the mtDNA because of oxidative defects in oxidative phosphorylation.
aerobic tissues such as Brain (neuropathies) and Muscle cells (myopathies)
What is the name of programmed cell death and what is the mechanism of this.
Apoptosis- PORES in mitochondrial membrane= CYT C leaves= binds and makes CASPASES= PROTEINS that carry out APOPTOSIS
What element can cause tiredness? How?
insufficient Iron levels may cause tiredness because of the effects it has on proteins in the ETC.
