TCA & ETC Flashcards
pyruvate enters mitochondria through ——-, then into matrix throug ——–
porins
mitochondrial pyruvate carrier (MPC)
byproducts of transition reaction
CO2 and NADH
transition reaction occurs via….
pyruvate dehydrogenase complex (PDH)
3 parts of PDH and cofactors they work with
E1 - TPP
E2 - CoA and lipoate
E2 - FAD and NAD+
NAD+ cofactor structure and chemistry
FAD cofactor structure and chemistry
CoA structure and chemistry
TPP cofactor structure and chemistry
Lipoate cofactor structure and chemistry
uses swinging arm mechanism between enzyme complexes in transition rxn
lipoic acid (E2)
substrate channeling
transfer of intermediates from one enzyme to another without release into solution
used in transition reaction
reaction types in TCA (5)
condensation
dehydration
oxidative decarboxylation
SL phosphorylation
hydration
step 7 is highly stereospecific, requiring…
trans fumarate
L-malate
ATPs per NADH and FADH2
2.5 per NADH
1.5 per FADH2
regulation of citrate synthase
citrate and ATP
regulation of isocitrate dehydrogenase
NADH and ATP
regulation of a-ketoglutarate dehydrogenase complex
succinyl CoA and NADH
3 enzymes of TCA regulated
citrate synthase
isocitrate dehydrogenase
a-ketoglutarate dehydrogenase complex
fatty acids enter TCA through…
transition reaction
alanine, glycine, threonine, cysteine, serine, and tryptophan enter TCA through…
pyruvate
isoleucine enters TCA through…
Acetyl CoA
leucine, lysine, phenylalanine, tyrosine, and tryptophan enter TCA through
acetoacetate to Acetyl CoA
arginine, proline, histidine, and glutamine enter TCA through
glutamate to a-ketoglutarate
isoleucine, valine, methionine and threonine enter TCA through
succinyl CoA
tyrosine and phenylalanine enter TCA through
fumarate
asparagine and aspartate enter TCA through
oxaloacetate
how are pyrimidines made from TCA?
oxaloacetate to asparagine/aspartate to pyrimidines
how are fatty acids and sterols made from TCA?
from citrate
how are purines made from TCA?
a-ketoglutarate to glutamate
how are heme and porphyrins made from TCA?
from succinyl CoA
delta G of ETC
30.6 kJ/mol
in ETC, protons are pumped from —– to ——
from matrix (N) to intermembrane space (P)
COMPLEX I
- nucleotide
- Fe-S clusters
- two portions
- electron carrier
- protons pumped
- flavin mononucleotide (FMN)
- 8 clusters
- membrane arm and peripheral arm
- NADH
- 4 protons pumped
NADH passes —- e- to FMN, which are passed….
eventually end up….
and transferred to….
2e- to FMN
passed through Fe-S clusters
end up on coenzyme Q
QH2 travels to complex III
COMPLEX II
- synonymous with…
- Fe-S clusters
- prosthetic group
- electron carrier
- reaction
- protons pumped
- synonymous with succinate dehydrogenase
- 3 clusters
- heme prosthetic group
- FADH2
- succinate oxidized to fumarate
- 0 protons pumped
FADH2 passes e- to….
which travels to…
Q
travels to complex III
COMPLEX III
- Fe-S clusters
- cytochromes
- protons pumped
- 1 cluster
- cyt b, cyt c, cyt c1
- 4 protons pumped
QH2 binds to ——–, and transfers 1 e- to—– and 1 e- to ——–
they then move to ….
complex III
1 e- to Fe-S, and the other to cyt b
e- from Fe-S goes to cyt c1, then to cyt c
e- from cyt b enters Q-cycle
cyt c moves to complex IV
Q cycle occurs because…
there is only 1 Fe-S cluster on complex III, but there are 2 electrons to be dropped off, so for every QH2 that drops off electrons the process has to happen twice
COMPLEX IV
- Fe-S clusters
- cytochromes
- ions present
- protons pumped
- 0 clusters
- cyt a and cyt a3
- copper ions present
- 2 protons pumped
cyt c transfers e- to…..
then they are transferred to….
then to…
cyt a
copper
cyt a3
to O2, forming water
force that turns ATP synthase
proton motive force
subunits of ATP synthase
F0 and F1
ATP synthase rev/sec
300
function of malate-aspartate shuttle
allows NADH generated in glycolysis to enter mitochondria
function of glycerol-3-phosphate shuttle
location
downside
same function as malate-aspartate
used in brain, muscle, brown adipose
loses 1 ATP/molecule glucose
inhibitors/uncouplers of ETC
examples
function
2-4-dinitrophenol
valinomycin
bring H+ back into matrix, decreasing efficiency
malate-aspartate shuttle
glycerol-3-phosphate shuttle
