Bioenergetics Flashcards
how many respiratory chains does human mitochondrial DNA produce
16
what occurs in the mitochondrial matrix
TCA cycle
beta-oxidation
urea cycle
amino acid synthesis
mitochondrial protein synthesis
what starting materials does the TCA cycle produce
amino acids
porphyrins (haem, chlorophyll)
purines and pyrimidines
what is the inner mitochondrial membrane primarily composed of
protein
features of the outer mitochondrial membrane
highly permeable
analogous to bacterial outer membrane
rich in porin and helical membrane proteins
features of a voltage dependent anion channel
privides low barrier to exchange ATP/ADP
the pore is lined with a positive charge
contact sites between IMM and OMM
how does the OMM interact with other organelles
via mechanical links
what is mitochondrial trafficking
movement of mitochondria along microtubules
driven by kinesin and dynein
how are the motor proteins linked to the mitochondria
Miro - integral OMM protein
Milton - adaptor protein
function of mitochondrial contact site
exchange of lipids between organelles
mediate Ca2+ signalling from ER to mitochondria
features of the IMM
site of energy generation
rich in proteins involved in respiratory chain
evolved to optimise restricted diffusion and localisation of reactions
contains transporters to move substances out into the cell
what does the F1 donate to in the F1F0-ATP synthase
its the water soluble head
responsible for ATP biosynthesis
what does F0 donate to in the F1F0-ATP synthase
transmembrane domain
couples proton transport to catalytic cycle
two half channels
proton transport link to transport
function of MICOS (mitonchondrial contact sites)
drives membrane invagination
mix60delta large lamellar structure
what is MICOS composed of
Mic10
Mic60
features of Mic10
2TMD with TMD Glycine motif and positive loop
forms large oligomeric complexes
requires cardiolipin
why is there such elaborate geometry
localisation of reactions:
ETC localised on cristae
efficient substrate transprort H+ gradient localised
restricts membrane diffusion gradient
what are both IMM and OMM both poor in
sterols
features of Mic60
forms the core of the complex
makes contact with the OMM
function of ATPase dimerization
drives membrane curvature
abolish dimerization - bridging membranes
ATP/ADP shuttle features
RRRMMM nucleotide binding motif
2 x 6 TMD/dimer
what is Em
a measure of a chemical species ability to acquire electrons and thereby be reduced
what does a high Em indicate
a high affinity for electrons
what can be denoted from Em
the potential at which the compound is half oxidized and half reduced
how many electrons do flavins carry and what is their deltaEm
2
0.2V
features of ubiquinone
2 electron carrier
membrane bound - large isoprenoid chain
deltaEm of 0.045V
features of FeS centres
1 electron carrier - irrespective of amount of Fe atoms
linked via Cys/His
delta Em of 200-250mV
what are the delta Em’s of haem a/b/c
a - 385mV
b - 0.07mV
c - 0.254mV
how do electrons travel the distance between redox centres
quantum tunnelling
function of transverse helices
coordinate conformational change
stabilize complex
how many electrons pass through the complex for every 4 H+
2 electrons
where are the ubiquinone binding sites on complex III
opposite sides of the bilayer, P and N
