oxidative phosphorylation Flashcards
what is the essence of oxidative phosphorylation
High energy electrons (carried by NADH and FADH2) used to reduce O2 to H2O
their energy is used to pump protons from the mitochondrial matrix to the intermembrane space
protons flow back across the membrane, following their concentration gradient
energy of proton flow is used to phosphorylate ADP to ATP
Electron flow in the respiratory chain
electrons flow down the transport chain from negative to more positive redox potential
big jumps in redox potential equate to big changes in G
these changes in free energy can be harnessed
first stage of oxidative phosporylation
electron transport
the second stage of oxidative phosphorylation
ATP synthesis
the electrochemical gradient of H+ across mitochondrial inner membrane
energy stored in this gradient can be used to synthesise ATP
are electron transport and ATP synthesis catalysed by the same proton pump
no
which cycle generates NADH
TCA cycle
the second stage of oxidative phosphorylation
ATP synthesis
electrochemical gradient of H+ out of the mitochondrial inner membrane
where are the four multisubunit complexes
in the inner mitochondrial matrix
where do the electrons from NADH enter in the electron transport chain
complex 1
where do the electrons from FADH2 enter in the electron transport chain
complex 11
is NADH oxidized or reduced in this process
oxidised, losing the H
where do the electrons ultimately get transferred on to
O2 to form H2O
how many of the respiratory complexes pump H+, and which ones are they
3
1,3,4
are there more protons in the intermembrane space or the matrix
intermembrane space
what happens with all the protons in the intermembrane space
forms an electrical field with the matrix side more negative
explain the electrochemical gradient
electron transport is energetically favourable
coupled to proton pumping
generates a membrane potential (large force)
generates a concentration gradient (smaller force)
other names for ATP synthase
mitochondrial ATPase
F1F0ATPase
what does F1 subunit do
protrudes into the mitochondrial matrix
what is the F0 subunit
it is a hydrophobic complex in the inner membrane which contains protein channels
what subunits form stator
alpha
beta
gamma
which subunits form the rotor
y and e
what turns the rotor
flow of protons
what do conformational changes lead to
ATP synthesis
give a summary of oxidative phosphorylation
oxidation of food stuffs to CO2 produces some ATP and releases electrons
electrons are accepted by organic co-factors and transferred to the respiratory chain (this recycles co-factors)
respiratory chain transfers electrons onto O2, producing H2O
the energy of electrons is used to create a proton gradient
energy of the proton gradient is used to drive ATP synthase
ATP synthase produces ATP
is NADH is oxidized to NAD+ what is the P/O ratio
2.5
is FADH2 is oxidized to FAD what is the P/O ratio
1.5
balance of glycolysis production
2ATP + 2 NADH + H+
balance of pyruvate dehydrogenase production
2NADH + H+
balance of TCA cycle production
6 NADH + H+ + 2FADH2 + 2ATP
how many ATP molecules can one glucose molecule yield
30-32
list things about OXPHOS diseases
common degenerative disease
involves mutations in the mitochondrial or nuclear DNA
pathology becomes worse with age
(with age spontaneous mutations accumulate)
symptoms usually appear in tissues with highest ATP demands ( nervous system, heart, skeletal muscle, kidneys)
the electrochemical gradient is generated while electrons do what
flow from NADH/FADH2 to O2 via complexes 1-4
how is the electrochemical gradient dissipated?
through the ATP synthase, generating ATP
