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Ch. 20-21
Ch. 20-21
114
Biochemistry
Undergraduate 3
01/29/2018

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Term
electron transport chain aka respiratory chain
Definition
4 large protein complexes that are embedded in the inner mitochondrial membrane
Term
where the electron transport chain is located
Definition
inner mitochondrial membrane
Term
cellular respiration
Definition
generation of high-transfer-potential electrons by the citric acid cycle, the respiratory chain, and the accompanying synthesis of ATP
Term
depiction of a simple overview of oxidative phosphorylation
Definition
[image]
Term
where the flow of electrons thru the electron transport chain takes place
Definition
inner mitochondrial membrane
Term
cristae
Definition
folds in the mitochondrion's inner membrane
Term
the 2 compartments of the mitochondrion
Definition
1: intermembrane space
2: matrix
Term
permeability of the mitochondrion's outer membrane
Definition
very permeable
Term
why the mitochondrion's outer membrane is very permeable
Definition
because it contains many mitochondrial porins, which create pores
Term
function of mitochondrial porin
Definition
regulates flux of molecules crucial to the function of cellular respiration
Term
permeability of mitochondrion's inner membrane
Definition
intrinsically permeable to nearly all ions and polar molecules
Term
matrix side
Definition
inside mitochondrion's inner membrane
Term
cytoplasmic side
Definition
intermembrane space in mitochondrion; called this because it is freely accessible to most small molecules in the cytoplasm cytoplasm
Term
simple depiction of the anatomy of a mitochondrion
Definition
[image]
Term
what oxidative phosphorylation does to O2
Definition
reduces it to water
Term
how oxidative phosphorylation reduces O2 to water
Definition
using electrons from NADH and FADH2
Term
electron transport chain
Definition
set of membrane proteins in which the transfer of electrons to reduce O2 to water takes place
Term
a conversion of potential that occurs in oxidative phosphorylation
Definition
the electron-transfer potential of NADH or FADH2 being converted into the phosphoryl-transfer potential of ATP
Term
how phosphoryl-transfer potential is expressed
Definition
ΔG°'
Term
reduction potentyial
Definition
expression for electron transfer potential
Term
how reduction potential is expressed
Definition
ΔE0'
Term
redox couple
Definition
substance that exists as oxidized and reduced forms
Term
how the reduction potential of a redox couple is determined
Definition
by measuring the electromotive force generated by a sample half cell connected to a standard reference half cell
Term
depiction of how redox potential is measured
Definition
[image]

electrons flow thru the wire and ions flow thru the agar bridge
Term
the reduction potential of the X:X- couple
Definition
the observed voltage at the start of the experiment
Term
the reduction potential of the H+:H2 couple
Definition
defined to be 0 volts
Term
what a positive reduction potential (ΔE0') indicates
Definition
accepts electrons
Term
what a negative reduction potential (ΔE0') indicates
Definition
donates electrons
Term
F
Definition
faraday proportionality constant (96.48 kJ mol-1 V-1, or 23.06 kcal mol-1 V-1)
Term
relationship between ΔE0' and ΔG°'
Definition
ΔG°' = -nFΔE0'
Term
oxidant
Definition
electron acceptor
Term
reductant
Definition
electron donor
Term
the driving force of oxidative phosphorylation
Definition
the electron-transfer potential of NADH or FADH2 relative to that of O2
Term
where does the energy that produces the proton gradient to make ATP come from?
Definition
the energy released by the reduction of each electron carrier
Term
repriasome
Definition
supramolecular complex composed of complexes that carries electrons down the electron transport chain
Term
depiction of the components of the electron transport chain
Definition
[image]
Term
why FADh2 derived electrons pump fewer protons and ATP than NADH derived electrons
Definition
electrons from FADH2 feed into the chain downstream from those from NADH because those from FADH2 have lower reduction potential
Term
why electrons from FADH2 feed into the chain downstream from those from NADH
Definition
because those from FADH2 have lower reduction potential
Term
the 2 types of Fe proteins in the electron transport chain
Definition
1: iron-sulfur proteins aka nonheme-iron proteins
2: cytochromes, which are components of heme prothetic groups
Term
cytochrome
Definition
Fe containing protein that is a component of a heme prosthetic group
Term
another metal that can participate in the electron transport chain
Definition
Cu
Term
how electron transfer works for quinones
Definition
for quinones, electron-transfer rxns are coupled to proton binding and release
Term
how the electron transport chain creates a proton gradient
Definition
electron flow within it leads to the transport of protons accross the inner membrane
Term
a protein complex that does not pump electrons
Definition
succinate-Q reductase
Term
where the electrons from NADH enter the electron transport chain
Definition
at NADH-Q oxidoreductase (complex 1)
Term
depiction of the electron transport chain's complexes
Definition
[image]
Term
depiction of coupled electron-proton transfer rxns thru NADH-Q oxidoreductase
Definition
[image]
Term
what the Q cycle does
Definition
funnels electrons from a 2 electron carrier to a 1 electron carrier and pumps protons
Term
the Q cycle
Definition
the mechanism for the coupling of electron transfer from Q to cytochrome C to transmembrane proton transport
Term
depiction of the Q cycle
Definition
[image]
Term
depiction of the cytochrome oxidase mechanism
Definition
[image]
Term
depiction of proton transport by cytochrome c oxidase
Definition
[image]
Term
depiction of the electron-transport chain
Definition
[image]
Term
some dangerous radicals that can form from O2
Definition
-superoxide (O2-) -peroxide (O22-)
Term
reactive oxygen species
Definition
-superoxide (O2-) -peroxide (O22-) -hydroxyl radical (OH•)
Term
some things reactive oxygen species can cause
Definition
-aging
-some other diseases
Term
superoxide dismutase
Definition
catalyzes the conversion of 2 superoxides into hydrogen peroxide and molecular oxygen
Term
depiction of the function of superoxide dismutase
Definition
[image]
Term
catalase
Definition
catalyzes the dismutation of hydrogen peroxide into water and molecular oxygen
Term
depiction of the function of catalase
Definition
[image]
Term
dismutation
Definition
rxn in which a single reactant is converted into 2 different products
Term
ATPase
Definition
protein protons move thru to generate ATP
Term
chemostatic hypothesis
Definition
proposes that electron transport and ATP synthesis are coupled by a proton gradient across the inner mitochondrial membrane

basically says that flow of protons drives production of ATP by ATP synthase
Term
how electron transport and ATP synthesis are coupled
Definition
by a proton gradient across the inner mitochondrial membrane
Term
depiction of the chemostatic hypothesis
Definition
[image]
Term
proton-motive force
Definition
the energy rich, unequal distribution of protons across the inner mitochondrial membrane
Term
the 2 components of the proton motive force
Definition
1: chemical gradient
2: charge gradient
Term
chemical gradient for protons
Definition
can be represented as a pH gradient
Term
charge gradient
Definition
created by the positive charge on the unequally distributed protons forming the chemical gradient
Term
how protons are transported out of the matrix into the intermembrane space
Definition
electron transfer thru the respiratory chain leads to the pumping of protons
Term
how to calculate proton-motive force
Definition
proton-motive force (Δp) = chemical gradient (ΔH) + charge gradient (Δψ)
Term
the respiratory chain and ATP synthase are biochemically separate. what links them?
Definition
only the proton-motive force
Term
depiction of the link between the respiratory chain and ATP synthase
Definition
[image]
Term
how NADH oxidation is coupled to ATP synthesis
Definition
1: electron transport generates a proton-motive force
2: ATP synthesis by ATP synthase is powered by a proton-motive force
Term
depiction of ATP synthase
Definition
[image]
Term
what makes each of the 3 β subunits different?
Definition
they each interact with a different face of the γ subunit
Term
how formation of cristae makes ATP synthesis more efficient
Definition
localizing the proton gradient to where the ATP synthases are
Term
depiction of how ATP synthase assists in the formation of cristae
Definition
[image]
Term
the rxn ATP synthase catalyzes
Definition
formation of ATP from ADP and orthophosphate ADP3- + HPO42- + H+ <--> ATP4- + H2O
Term
the 3 different functions performed by the 3 active sites in ATP synthase
Definition
1: trapping of ADP and Pi 2: ATP synthesis 3: ATP release and ADP and Pi binding
Term
the 2 parts of ATP synthase
Definition
1: moving unit (rotor) consisting of c ring and γε stalk
2: the stationary unit (stator) consisting of the remainder of the molecule
Term
depiction of the distinct ATP synthase nucleotide-binding sites
Definition
[image]
Term
order in which subunits of ATP synthase change state
Definition
T --> O --> L

repeatedly rotates counterclockwise
Term
depiction of a binding-change mechanism for ATP synthase
Definition
[image]
Term
what drives the rotation of the γ subunit in ATP synthase?
Definition
hydrolysis of ATP
Term
depiction of the components of the proton-conducting unit of ATP synthase
Definition
[image]
Term
what powers the rtation of the c ring in ATP synthase?
Definition
movement of protons thru the half channels from high proton c'tration of intermembrane space to low proton c'tration of matrix
Term
depiction of proton motion across the membrane
Definition
[image]
Term
depiction of the proton path thru the membrane
Definition
[image]
Term
number of c subunits in ring vs. efficiency of ATP synthase
Definition
the more subunits in the ring, the less efficient, that is, the more protons needed to synthesize 1 ATP
Term
depiction of an overview of oxidative phosphorylation
Definition
[image]
Term
how electrons from intermembrane space enter matrix
Definition
shuttles
Term
how NADH is reoxidized to NAD+
Definition
electrons from NADH, rather than NADH itself, are carried across the mitochondrial membrane
Term
the glycerol 3-phosphate shuttle
Definition
introduces electrons from NADH into the electron transport chain
Term
depiction of the glycerol 3-phosphate shuttle
Definition
[image]
Term
malate-aspartate shuttle
Definition
transfers electrons from NADH to oxaloacetate, forming malate
Term
depiction of the malate-aspartate shuttle
Definition
[image]
Term
the major function of oxidative phosphorylation
Definition
to generate ATP from ADP
Term
ATP-ADP translocase
Definition
transports ATP out of matrix and ADP into matrix
Term
when ATP enters the mitochondrial matrix
Definition
only when ADP is present
Term
when ADP enters the mitochondrial matrix
Definition
only when ATP is present
Term
depiction of the mechanism of ATP-ADP translocase
Definition
[image]
Term
ATP synthasome
Definition
large complex of proteins that provide the substrates needed for ATP synthesis
Term
depiction of the mitochondrial transporters
Definition
[image]
Term
cellular respiration is regulated by...
Definition
the need for ATP, since it's the ultimate and product of cellular respiration
Term
how many molecules of ATP are formed when glucose is completely oxidzed to co2?
Definition
about 30
Term
which step of cellular respiration generates most of the ATP?
Definition
oxidative phosphorylation (26 of 30)
Term
how many ATP does anaerobic glycolysis yield?
Definition
2
Term
the rate of oxidative phosphorylation is determined by...
Definition
the need for ATP
Term
when electrons flow thru the electron transport chain to O2
Definition
they usually do this only when ADP is simultaneously phosphorylated to ATP
Term
respiratory control or acceptor control
Definition
regulation of the rate of oxidative phosphorylation by the ADP level
Term
when electrons flow from fuel molecules to O2
Definition
only when ATP needs to be synthesized
Term
depiction of how energy charge regulates the use of fuels
Definition
[image]
Term
depiction of some things proton gradient can be used for
Definition
[image]
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