Electron Transport Chain Flashcards
Incomplete oxidation in ketogenesis results in?
incomplete oxidation of fatty acids resulting in less energy
Anything produced in the cytoplasm is transported to?
the mitochondrial matrix
What is the role of NADH and FADH2 in the electron transport chain?
The NADH and FADH2 give up their electrons to reduce molecular O2 to H2O.
ETC takes place in _______ where all of the electron carriers are present.
inner mitochondrial membrane
What is the function of the electron transport chain?
The function of ETC is to facilitate the controlled release of free energy that was stored in reduced cofactors during catabolism.
What plays a critical role in forming and utilizing the proton gradient to synthesize ATP?
mitochondrial structure
Where in the mitochondria is ATP synthesized?
matrix
When is energy released?
when electrons are transported from higher energy NADH/FADH2 to lower energy O2
The coupling of ATP synthesis to NADH/FADH2 oxidation is called?
oxidative phosphorylation
______ is responsible for 90% of total ATP synthesis in the cell.
oxidative phosphorylation
The oxidized compound [loses/gains] electrons.
loses
The reduced compound [loses/gains] electrons.
gains
What acts as a mechanism for storing energy?
reduction
The electron transport chain is in which part of the mitochondria?
in the cristae (the folded inner membrane) of the mitochondrion
Most of the electron transport chain’s components are?
proteins
A _______ and a _______ shuttle between protein complexes.
lipid soluble coenzyme (Q); water soluble protein (cyt c)
How does the ETC work?
Electrons drop in free energy as they go down the chain and are finally passed to O2, forming H2O.
ATP synthesis (phosphorylation) must be coupled to?
to the generation of a H+ reservoir/pH gradient (oxidation) between the mitochondrial membranes
Every 4 H would constitute _____ ATP.
1
When electrons are transported along the components of the ETC, what happens to the accompanying protons?
they are released
Part of the free energy harvested during the ETC is used to?
to pump protons out of the mitochondrial matrix
The resulting uneven distribution of protons generates?
a pH gradient and a charge gradient across the inner mitochondrial membrane
The electrochemical potential energy generated by the pH and charge gradients is called _________.
Proton Motive Force
The return of protons to the mitochondrial matrix is coupled to?
ATP synthesis
Most drugs interfere with complex 4 which gives what effects?
side effect, carbon monoxide, cyanide which can kill because it blocks the ETC and results in no energy
Electrons move from a carrier with [low/high] reduction potential toward carriers with [lower/higher] reduction potential.
low, higher
What is the only enzyme in the Citric Acid Cycle that is membrane bound? (bound to inner mitochondrial membrane)
succinate dehydrogenase
Cytochrome Oxidase is directly linked to?
Complex 4
_________ and ________ are affected during apoptosis in pesticides
ubiquinone, cyt c
Briefly explain the chemiosmotic hypothesis
Basically coupling electron flow through the ETC to ATP synthesis
The respiratory complexes are _________.
proton pumps
As electrons pass through complexes _________, hydrogen ions are pumped across the inner mitochondrial membrane into the intermembrane space
I, III, and IV
The proton concentration in the intermembrane space [decreases/increases] relative to the mitochondrial matrix
increases
The proton-motive force is generated as a result of which two factos?
1) Difference in pH and 2) Difference in electrical potential, delta si, between intermembrane space and the mitochondrial matrix.
What is complex V?
ATP synthetase complex
ATP synthesized in the matrix is transported out of the matrix via an ___________ (an antiport) also coupled to proton motive force
ATP/ADP translocase
What is the malate-aspartate shuttle?
a biochemical system for translocating electrons produced during glycolysis across the semipermeable inner membrane of the mitochondrion for oxidative phosphorylation in eukaryotes
What is the glycerol-3-phosphate shuttle?
a mechanism that regenerates NAD+ from NADH, a by-product of glycolysis. Its importance in transporting reducing equivalents is secondary to the malate-aspartate shuttle
Why do we need the malate-aspartate shuttle?
to shuttle NADH to the mitochondrial matrix
What does dinitrophenol do?
Dinitrophenol uncouples proton motive force and ATP synthesis
_______ is the molecular motor of life.
ATP synthase complex
What is done to protect vital organs during animal hibernation?
uncoupling proteins which generates metabolic heat
ATP synthesis can be “uncoupled,” if the proton gradient is _______________.
prematurely dissipated or impeded
What are involved in site complex I?
amytal & rotenone
What is involved in site complex III?
antimycin A
What is involved in site complex IV?
Cyanide (CN-), Sodium azide (N3-), CO
What is amytal?
a type of barbiturate used in the treatment of severe sleeping disorders
What is rotenone?
used as a broad-spectrum insecticide, piscicide, and pesticide
What is antimycins?
active ingredient in Fintrol, a chemical piscicide (fish poison) used in fisheries management and in the catfish industry
Mitochondrial DNA is [paternally/maternally] inherited.
maternally
______ polypeptides required for oxidative phosphorylation are coded by ________.
13; mtDNA
Defects in oxidative phosphorylation are a result of alterations in ________.
mtDNA
Which tissues are affected by defects in oxidative phosphorylation?
CNS, Skeletal & heart muscles and Liver
