ETC (mini test 1) Flashcards
What are the other names for ETC?
-respiratory chain
-oxidative respiration
-oxidative phosphorylation
Its a conversion of reducing equivalents like NADH and FADH2 to O2 yielding energy for the generation of ATP and water. The best model to describe this mechanism is called the chemiosmotic theory
What is the driving force of the ETC?
oxygen
How many NADH go into ETC (was made in all the steps before)?
10 NADH
was produced by
-GAP DH
-PDH
-IDH
-alpha KG DH
-malate DH
How many FADH2 go into ETC (was made in TCA)?
2 FADH2 (was done with SDH)
How many ATP and GTP were made before ETC by just substrate level phosphorylation?
2 ATP from phosphoglycerate kinase and pyruvate kinase (step 7 and 10 of glycolysis)
2 GTP from 2 rounds of TCA with succinyl CoA synthetase/ succinate thiokinase
Which membrane of the mitochondria is permeable to most small molecules?
outer membrane
What part of the mitochondria is an acidic space between the outer and inner membrane?
intermembrane space
Which part of the mitochondria is selectively permeable and only VIP molecules can cross? It contains the respiratory chain components and enzyme complex for ATP synthesis (lots of ETCs)
Inner membrane
What are 6 VIP molecules?
1) pyruvate
2) malate
3) citrate
4) aspartate
5) PEP
6) carnitine
Which part of the mitochondria contains PDH, enzymes of the TCA, FA oxidation, and AA oxidation?
mitochondrial matrix
What are some CoQ rich foods?
-organ meats (especially meats that require large amounts of energy like liver, heart brain)
-sardines
-peanuts
-spinach
Complex 1, NADH DH complex, transfers electrons from where to where?
NADH > FMN> FeS> UQ
Complex 2, SDH complex, transfers electrons from where to where?
succinate> FAD> FeS> UQ
Complex 3, cytochrome C complex or also known as cytochrome reductase complex, transfers electrons from where to where?
UQ> cyt b> cyt c
Complex 4, cytochrome oxidase complex, transfers electrons from where to where?
cyt c > cyt a> cyt a3> O2
Why don’t complex 1 and 2 in ETC communicate?
its a safety mechanism, if one fails then the other way will still work
The flow of electrons are accompanied by the movement of protons out into the….
inter membrane space
CoQ is important for what bodily functions?
-important for heart function (the more CoQ = healthier)
-important for immune function, need energy for immunity
-also important for brain function
What is complex 1 called?
NADH DH complex
Where does ubiquinone (UQ) move to and from?
either from complex 1 to 3 or from 2 to 3
DOES NOT go 1,2,3
What is the substrate for complex 2 of ETC?
succinate
What is complex 2 of ETC called?
SDH complex
Complex 2 of ETC is usually with SDH, aka why its called SDH complex. But what other molecules are also here and can donate H?
glycerol 3 P DH or acyl CoA DH
What is complex 3 called?
cytochrome reductase or cytochrome C
Is cytochrome C an integral or peripheral protein?
peripheral protein
Is cytochrome B an integral or peripheral protein?
integral protein
Are cytochrome A and A3 integral or peripheral proteins?
integral proteins
What is complex 4 of ETC called?
cytochrome oxidase
What is complex 5 of ETC called?
ATP synthase
For the ATP synthase, each H makes ___ ATP
1
What complexes in ETC have a proton pump?
1, 3, and 4 (so 3 H+ were released in total and 3 ATP will be made)
if the ETC starts from complex 2, then only 2 H+ were released and 2 ATP will be made
What is the reducing power from the highest to lowest?
-NADH
-FAD or FMN
-FeS
-UQ
-Cyt b
-Cyt C
-Cyt A
-Cyt A3
-oxygen
Which complexes in ETC require Fe?
1-4 (this is the most important mineral in ETC!!!)
What complex in ETC requires Cu?
complex 4
Which complex in ETC requires Mg?
complex 5
What is a Cu rich food?
dark chocolate
Complex 2 in ETC is linked with what other pathways?
TCA, glycolysis, and beta oxidation
TCA bc of SDH
glycerol 3 P DH = glycolysis
acyl CoA DH = beta oxidation
What electron carriers interact reversibly with dehydrogenases and are water soluble?
NAD+ and NADP+
What do dehydrogenases prefer?
NAD+
but some will use both like malic enzyme
or use just NADP+ like G6P DH
NADH transports electrons to ETC, generating ____ ATP
3
NADPH transports electrons for ____________ reactions
anabolic
What are the prosthetic groups of dehydrogenases?
FMN and FAD
Which coenzymes are very tightly bound to an enzyme, are not freely diffusible, and are located in the inner mitochondrial membrane (ex: SDH)?
FMN and FAD
electron carried by FADH2 generates _____ ATPs
2
UQ is not a protein but is an….
oil soluble biomolecule and is an antioxidant
What transports electrons to complex 3 in ETC?
UQ
What are cytochromes?
-iron containing electron transfer proteins
-iron is in the heme prosthetic group
-iron coordinates in the porphyrin ring structure
-cytochrome A and A3 are integral membrane proteins
-cytochrome B is an integral protein
-cytochrome C is a soluble/peripheral protein
Fe is not coordinated in heme, but with sulfur groups of ____________ residues within the protein
cysteine
FeS proteins often act as….
intermediary electron carriers
What is proton motive force?
proton gradient developed by the ETC creates a difference in pH and charge across the membrane
it is used to drive the synthesis of ATP as protons move through ATP synthase down the proton gradient
The malate aspartate shuttle will generate how many ATP per NADH from glycolysis?
3 ATP
The glycerol 3 phosphate shuttle will generate how many ATP per NADH from glycolysis?
2 ATP
What complexes of ETC are oxidation reactions?
1-4
What complex is a phosphorylation rxn in ETC?
complex 5 (substrate level phosphorylation)
What is the coupled reaction in ETC?
complexes 1-4 is coupled with complex 5
Anything that can remove H+ from proton pump is an _____________
uncoupler
In brown fat, _____________ (uncoupler protein) short circuits the proton motive force in the inner membrane and energy is not converted to ATP but is released as heat (this is essential for babies and animals in hibernation)
thermogeninin
The oxidation and ATP synthesis coupling can be uncoupled with _____________ (transports ions across a cell membrane) and 2,4 dinitrophenol and can cause person to overheat easily
ionophores
Calcium induces the synthesis of an uncoupler protein called _______, which may assist some individuals in maintaining a healthy weight/weight loss. This also generates heat. If the person has a lot of this protein, then they are fit bc all their food intake changes to high energy electrons and then H and heat. If it went to ATP, then it can be used to become fat
UCP2
There are 2 types of inhibitors of ETC preventing H+ gradient formation (inhibitors of proton pumps- 1,3, and or 4). What are they?
1) cyanide and CO inhibit complex IV/cytochrome C/cytochrome oxidase (if this is blocked then it can result in quick death)
2) barbiturates inhibit complex 1/ NADH DH complex (if blocked, ETC can still make ATP from complex 3 and 4 but its not enough and will put you into a deep sleep)
What medication can be used to inhibit ATP synthase/complex 5 in bacteria but NOT humans?
antibiotics
