lecture 18-20 Flashcards
triangle G of ATP to ADP
-7.3 (very favorable reaction)
ADP to ATP
photosynthesis
oxidation of fuel molecules
(oxidation phosphorylation)
oxidation phosphorylation
creates ATP
ATP
adenosine triphosphate
people usually store a 4 minute supply of
ATP
oxidation phosphorylation
generation of ATP by the transfer of electrons to O2
any condition that deprived the tissue of O2 or ____ oxidate phosphorylation create a serious medical conditions such as ____
inhibits
anemia
anoxia
compromised pulmonary/ cardiac function
RBC have no mitochondria so it relies exclusively on ___ for ATP
anaerobic glycolysis
LEO says GER
loss electron is oxidation
gain of electron is reduced
malate to oxaloacetate
malate dehygrogenase (NAD to NADH + H+
oxidant
compound the pulls electrons form other molecules (gets reduced)
reductant
compound that donates electrons to other moloecule (gets oxidized)
the free energy for the transfer of 2 electrons from NADH to 1/2 O2 is -52 kcal/mole. How does this compare to the energy required to make 1 ATP?
-7.3 kcal/mol
can make several ATP in one oxidation-reduction reaction
FADH2 will create__ energy then NADH
less
make up of mitochondria
two membranes
-outer membrane
protein channels that let most small molecules across
inter-membrane space
-inner membrane
highly folded (increase surface area)
impermeable to most ions
-where oxidation phosphorylation
matrix
-where TCA and fatty acid oxidation take place
where does TCA cycle and fatty acid oxidation occur
in the matrix of the mitochondria
oxidation phosphorylation occurs in the
inner membrane of the mitochondria
oxidative phosphorylation has two distinct processes that are normally tightly couples
electron transport chain
ATP synthesis
electron transport chain
NADH
-NADH-Q oxidoreductase
from the side
Succinate-Q reductase
Q
-Q-cytochrome c oxidoreductase
Cyt c
-cytochrome c oxidase
O2
why do we need proteins in ETC
- storing energy
- regulation
- protect cell from reactive intermediates
- NADH is stable, these proteins make the process go
prosthetic group- non peptide component of a protein that is ___ bound and is ____ biological activity
tightly
biologic
5 types of prosthetic groups that help ETC
flavin iron sulfur heme copper ions coenzyme Q
flavin mononucleotide- derived from vitamin ___aka.____
B2
riboflavin
carries electrons by changing numbers of double bonds
Iron sulfur complexes
variety of ways they can be arranged, iron is oxidized state 2+ or 3+, carries electron by changing oxidation state
heme
prosthetic group of cytochrome proteins
2+ or 3+ state of Iron (Fe)
carries electron by changing oxidation state
copper ions
oxidation state 1+ or 2+, essential trace mineral, increased copper can be lethal
Bedlington terriers make too much copper
type of dog that produces to much copper
Bedlington terriers
coenzyme Q
carries electrons by changing number of double bonds
very hydrophobic
stays inside inner-membrane of the mitochondria
three large protein complexes in the inner membrane of mitochondria that help with ETC
NADH Q oxidoreductase
Q cytochrome c oxidoreductase
cytochrome c oxidase
1st protein in the ETC that transfers electrons from NADH to Q
NADH Q oxidoreductase
NADH Q oxidoreductase
crosses the membrane
46 subunits
gives electrons from NADH to Q to form QH2
2nd protein in the ETC that transfers electrons from ubiquinol to cytochrome c
Q cytochrome c oxidoreductase
Q cytochrome c oxidoreductase
2nd protein in ETC
gives electrons from ubiquinol to cytochrome c
cytochrome c
small heme containing protein
located on the outer surface of the inner membrane
3rd protein of the ETC that transfers electrons from cytochrome c to O2 to form H20
cytochrome c oxidase
electrons from FADH2 are transferred to Q, for example, succinate dehydrogenase, which is an enzyme in the TCA cycle, transfers electrons to Q via ____
FADH2
ETC move __ through the chain pumping ___ into the ___. the electrons eventually leave with O to form ___
electrons
H
intermembrane space
water
reduction of oxygen to water generates several reactive intermediates called
superoxide anion
02^(.-)
negatively charged with unpairs electron (radical)
very reactive
superoxide anion is very ___ and must be kept at a very low level. Mitochondria are a significant source of reactive oxygen species.
reactive
as electrons flow through the ___, ___ are pumped from the ___ into the ___. The __ gradient across the inner membrane is used to drive ____.
chemiosmotic hypothesis-
ETC protons matrix intermembrane space proton ATP synthesis
___ uses proton gradient to generate energy as H (protons) are pumped back into matrix of mitochondria
ATP synthesis
proton gradient across the inner membrane
1.4 pH unit difference
very big difference!
proton gradient generated by other mechanisms such as ____ can work with ATP synthesis the same way that ___ does
proteins that pump protons when exposed to light
ETC
ATP synthesis stops if
proton gradient is neutralized or destroyed
ATP synthesis stops if
proton gradient is neutralized or destroyed
P:O ratio- ratio of ___ made per atoms of ___ reduced
ATPs
Oxygen
because electrons from FADHs bypass NADH-Q oxidoreductase, fewer ___ are pumped across the inner membrane and fewer ____ are synthesized
protons
ATP
FADH(from TCA cycle)
start at Q instead of 1st protein.
2.5 ATP = 1 NADH
1.5 ATP = FADH2
in P:O
P is ____
O is ___
phosphate going into ATP
Atoms of oxygen
FADH2 produces ___ ATP
1.5
NADH produces ___ ATP
2.5
ATP synthase
c ring and a subunits form the
proton channel through inner membrane
ATP synthase
alpha subunit has ___ partial membrane channels
2
ATP synthase
catalytic sites for ATP synthesis
3 Beta subunits
ATP synthase
alpha subunits help ___
beta subunits
ATP synthase
gamma subunit
acts as rotary engine
explain how ATP synthase works
protons move from alpha onto C ring and cause C ring to move- protons will go all the way around and leave by the lower alpha partial membrane channel
this process rotates gamma which changes the shape of B and alpha units which causes ADP to convert to ATP and be released into cell
ATP binding site of B subunit exist in three different ___
confirmations
L,O,T
L or loose: binds ___ and ___, but cannot synthesize ATP
ADP
Pi
ATP
T or Tight: can synthesize ___ from ADP and Pi, but cannot ___ ATP
ATP
release
O or open: has very low affinity for ___, which allows ATP to be ___. Can bind ADP and Pi
ATP
released
rotation of the ___ subunit driven by the ____ changes the confirmation of the ___ subunits.
gamma
proton gradient through alpha
Beta
T goes to ___, O goes to ___ L goes to ___
O
L
T
respiratory control- regulation of oxidative phosphorylation by the availabilty of ___
ADP
one mechanism contributing to respiratory control:
if ADP is not available, the proton gradient will ___. Because the flow of electrons through the ETC is tightly coupled to the pumping of protons, the flow if electrons will slow as it becomes more difficult to pump protons across the inner membrane. O2 consumption ___ and energy rich molecules are ___. other mechanisms likely contribute to respiratory control
increase
decreases
conserved
1 full turn of c ring would create ___ ATP
3
Respiratory control also affects TCA cycle- if oxidative phosphorylation slows due to low ADP, ATP will be high and NADH will increase in the matrix of the mitochondria. ATP and NADH both ___ enzymes in the TCA cycle
inhibit
Lower NAD+ and FAD also slow TCA cycle since they are key TCA ___
substrates
The key feature of chemical uncouplers is there ability to carry ___ across the inner membrane of the mitochondria back into the matrix
protons
in the presence of uncouplers, ATP synthesis is reduced, but ETC continues and in fact accelerates why?
uncouplers help move protons, makes it easier to move protons
**
brown fat is brown because of numerous
mitochondria
brown fat produces ___ which is especially important for ____
heat
newborns
hybernation
cold adaptations
not completely uncoupled, so some ___ is made. Uncoupling proteins is inhibited by ___ and activated by ___
ATP
GDP (similar to ADP)
free fatty acids
Chemical uncouplers are potentially dangerous because
causes profuse sweating, collapse, hyperthermia
makes person too hot
4 proteins needed for ETC
NADH -NADH-Q oxidoreductase -succinate Q reductase Q -Q-cytochrome c oxidoreductase cty c -cytochrome c oxidase O2=4 electrons given to H20
cyanogenic glycosides- plant carbs that release ___. Cyanide blocks ___
cyanide
cytochrome c oxidase (last protein of ETC)
cyanogenic glycosides are found in __ therefore ___ are most common victims because of their diet
grasses, seeds and some fruits, burning plastic
ruminants
how to treat cyanide
nitrites- they oxidize hemoglobin to methemoglobin which binds cyanide
hydroxocobalamin- form of vitamin B12 that binds cyanide
Thiosulfate- reaction with cyanide to form thiocyanate. reaction is enzymatically catalyzed
carbon monoxide- main effect is to block O2 transport by hemoglobin but its also blocks
cytochrome c oxidase (last protein of ETC)
treatment for carbon monoxide
oxygen therapy
**
rodenticide that is an ____. No known antidote
Bromethalin-
uncoupler- dissipated proton gradient
insecticide and piscicide. blocks NADH Q oxiodreductase
rotenone
a deficiency of oxygen reaching the tissues of the body. Can be caused by ___
hypoxia
shock, extreme blood loss
altitude
anemia
poor cardiac function
localized tissue anemia due to obstruction of the inflow of arterial blood such as a ____ .
ischemia
heart attack or stroke
vet example of ischemia
aortic thromboembolism in cats
twisted bowel in horses
____ is when ETC stops during tissue ischemia due to lack of ___. ETC complexes become fully reduced. When O2 is restored ___ escape from the ETC and form ____ and other reactive oxygen species.
Reperfusion injury
Oxygen
electrons
superoxide anion (O2^.-)
mitochondria have their own ___ and ___.
genes and proteins
most mitochondrial proteins are encoded in the ___, synthesized in the cytoplasm and then imported in to mitochondria.
nucleus
mitochondrial genetics- number of mitochondria per cell ___ .
Each mitochondria has multiple mitochondrial DNA, typically ___ copies of mitochondrial DNA per cell
100 to 1000
1000s
mitochondria are inherited form the ____
mother
mutation rate of mitochondrial DNA is ___ because
higher
ETC makes reactive agents (superoxide anions) that tend to attack DNA
a process called ___ can eliminate low function or defective mitochondria
mitophagy
neuro and muscle tissue are common sites of pathology due to their___ requirement for ATP production and therefor oxidative phosphorylation
high
symptoms of diseases involving mutations in mitochondrial DNA often have a ___ onset
late
