lecture 5: Kreb’s cycle and the electron transport chain (ETC) Flashcards
what is the first product that enters in the kreb cycle and how many of them are they
acetyl coa
2
what are 2 other named for the kreb cycle
Citric acid cycle
tricarboxylic acid cycle
what substance links gylcolysis and kreb cycel
acetyle coa
true or false, you only lose CO2 in pyruvate oxydation
false, you lose 2 CO2 on kreb cycle
what are the 2 co enzymes of the kreb cycle
FADH2 and NADH
what is FAD
flavin adenine dinucelotide
WHAT DOES FAD reduce to
FADH2
explain the reduction of the FAD
it can be reduced to FADH2 when it accepts 2 H+ and 2 electron
what is the structure of FAD
has two nitrogen groups to accept the Hydrogens and electrons
contains ADP and a riboflavin
how many carbons are in acetyle coa
2
how many carbons are in oxaloacetate
4
how does the kreb cycle start (ie how is citrate formed)
the 4 carbon oxaloacetate merges with the 2 carbon acetyl coa and you get citrate being formed
Explain the kreb cycle
1) Acetyle coa merges with oxaloacetate to form citrate
2) There are a series of metabolic reactions to get the 6 carbon citrate down to a 4 carbon succinyl coa
3) the two carbons that are lost become CO2 and are expired at the lungs
4) At many stages you get NAD+ being reduced to NADH by accepting electrons and hydrogen from the substates of the cycle
5) You also get reduced of FAD to FADH2 by the same manor
6) This cycle also generates 1 ATP by hydolysis of GTP which phosphorylates ADP to ATP
7) cycle will continue until succinyl coa is turned into oxaloacetate again
for every turn of the ckrebcycle, how many NADH+h are formed
3
FOR EVERY TURN OF THE KREB CYCEL, how many FADH2 are formed
1
for every turn of the kreb cycle, how many co2 formed
2
for every turn of the kreb cycle, how many atp is gormed
1
how many turns of the kreb cycle happen for the pyruvates coming down from pyruvate oxidation
2 total times (2 molecules of acetyle coa)
what is needed for the cycle to continue
acetyl coa
in total, what are the yields for 1 turn of the kreb cycle
3 nadh
1 fadh2
1 atp
2 carbon dioxide
how is atp formed in the kreb cycle
GTP (guanine triphosphate) gets hydolized and donates its phosphate to ADP to become ATP
where is Fad and NADh located
in the mitochondira
where is pyruvate located
in the cytosol and gets transported through the membrane by protein carriers
where is the kreb cycle performed
matrix
why is acetyl coa an important biomechanical junction
many substances (proteins, pyruvates, fatty acids) can be transromed into acetyl coa and enter the kreb cycle
where are teh 3 main places atp are formed
glycolysis
kreb
ETC
Where do the cofactors for ETC come from>
NADH comes from either
kreb cycle (3)
OR
glycolysis (2) under aerobbic conditions
FADH2
kreb cycle
when will the NADH go to the ETC from glycolsysi
2 NADH will come if it is not being used for lactate (only in aerbocib or resting conditions)
WHere is the NADH from the gylcosis found
in the cytosol and needs to go into tbe. matrix for ETC
True or false: the NADH and FADH2 that go to the ETC only come from kreb cycle
false they also can come from glycolysis under the proper conditions
how much ATP and NADH is formed from glycolysis
2 atp (net 2 nadh (from glyceradhyde 3 phosphate)
Does glycolysis happen in the mitochondiral matrix, the inner mitochondiral membrane or the cytosol
cytosol
Does kreb happen in the mitochondiral matrix, the inner mitochondiral membrane or the cytosol
matrix
Does ETC happen in the mitochondiral matrix, the inner mitochondiral membrane or the cytosol
inner mitochondiral membrane
True or false: the ETC is a single segment of proteins in the inner mitochondiral matrix
false, there are many proteins that rpeat themselves over and over
true or false: the ETC happens in the outer mitochondiral membrane only
false,
in the inner membrane only
what is the space between the two mitcohondrial membranes called
the intermembrane space
what does a complex mean (ETC)
a series of proteins attached
with an enxyme
what are the complexed of the ETC
COmplex 1, 2, 3, 4
what are the carries of the ETC (carrie the eelctrons)
CoQ and CytC
What complex does NADH come into contact with first
complex 1
what complex does FADH2 come into contact with first
complex 2
explain the electon transportation for NADH
1) NADH contacts at complex once and gets reduced to NAD
2) electrons are released and flow through the complex and to the COq
3) This energy allows the Hydrogen to flow through the complex 1 into the intermmebrane space
4) electron travels with Coq to complex 3 and another hydrogen moves up complex 3
5) electron is bound to Ctc and goes to complex 4 allowing another hydrogen to move through complex 4
6) electron is transfered to oxygen
do the electrons from NADH skip or pass through complex 2
skip it
is the coq for NADH mobile or immobile
mobile
is the coq for FAD mobile or imobile
immobile
where are the 3 places that the hydrogens ar pumped through
complex 1, 3 and 4
where do the hydrogens get pumped from and to
pumped from matrix
pumped to intermmebrane space
explain electron transport from FADH
1) FADH2 comes into complex 2 and loses its 2 electrons and hydrogens to become FAD
2) electrons travels through COq and go to complex 3 which allows hydrogens to pas through complex 3
3) electrons nbind to cyt C and pass through complex 4 allowing hydrogens to move through complex 4
4) electrons get bound to oxygen
what is the final electron acceptor
oxygen
how do hydrogens get pumped into the intermembrane space?
the electon pairs donate energy (since they have a charge) to allow the hydrogen to move through the complex
explain the oxygen as the final hydrogen acceptor
the elcetrons from the ETC bind onto the oxygen moleucle and form water
why is oxygen so impportant to the ETC
it accepts electrons therefore with more oxygen, bind more elcetrons, then NADH and FADH2 can continue to donate electrons
with inadqurate oxygenation consumption, electrons have no where to bind and ETC will slow
what is the last protein of the ETC
ATP synthase protein
what is the ATP syntahse protein
it is an intramembrane enzyme that helps the speed of hydrogen proteins going through it
pumps the hydrogens back to the matrix
true or false: ALL the complexes are considered to be intramembrane enzymes
false, complex 2 is only in the matrix
What happens as hydrogens pass through the intramembrane atp synthase
Hydrogens passing thoreugh have a lot of kinetic energy build up therefore it imparts chemical energy to the ADP which allows a free phosphate to bind to ADP and form ATP
True of false: for every hydrogen that passes through, you form atp
true
the hydrogens from NADH get taken up through complex…
1,3,4
the hydrogens of FADH2 go throug hthe compelx…
compelx 3 and 4
for every molecule of NADH how many hydrogens and therefore how many atp is formed
1 molecule NADH=3 hydrogens=3 atp
for every molecule of FADH2, how many hydrogens and therefore how many atp are formed
1 molecule FADH2= 2 hydrogens = 2 atp
true or false: the matrix has a postiive charge
false
it has a negative charge which creates an electrocheimical gradient
what is the reason hydrogens want to flow back into the matrix through ATP synthase protein>
There is a buildup of negative charge in the matrix of the mitochondira (since they are being pumped out) therefore this electrochemical attraction/gradient will cause the hydrogens to diffuse back into the matrix through atp synthase which will give you energy
what is another name for the COq transporter
ubiquinone
what is another name for complex threee
cytocochrome b-c1 complex
what is the name for CT c
cytochrome c
what is another name for the 4th complex
cytcohome oxidase complex
true or false: only Coq is mobile?
false, cyt c is also mobile
does complex 2 promote any hydrogen pumping/movement
no
without oxygen what happens (full picture)
wihout oxygen, cannot bind electrons therefore the metabolic process will be backed up
hydrogen movement will decrease
electron transport activity will decrease (NADH and FADH2 will start to increase)
kreb cycle will shut down
pyruvate to acetyle (which goes to kreb) will stop
Pyruvate will go to lactic acid instead of actyl coa
ETC and Chemiosmosis together is called..
oxidative phosphorylation
what is the part of the ETC that produces energy called (the part that allows protons to travel back into the ATP synthase for ATP)
chemiosmosis
