module 7- oxidative phosphorylation Flashcards
where does oxidative phosphorylation take place?
mitochondria
where does the generation of NADH & FADH2 occur?
mitochondrial matrix
where are electrons carriers located?
inner mitochondrial membrane
is the inner or outer membrane permeable to most small molecules?
outer
how does ATP get across inner membrane?
using transporters or shuttles
what does redox potential measure?
measures molecules tendency to donate or accept electrons
NADH is a strong ( ) agent and readily ( ) electrons & has ( ) E0
reducing, donates, negative
O2 is a strong ( ) agent and readily ( ) electrons & has ( ) E0
oxidizing, accepts, positive
oxidative phosphorylation depends on…
electron transfer
standard free energy change related to reduction potential reaction
ΔG°’ = -nFΔE0’
T or F: transfer of high energy electrons from NADH or FADH2 to O2 generates lots of energy
T
what is the final electron acceptor in the respiratory chain?
O2
what are the 2 products formed in the electron transport chain?
H2O & ATP
How many protons are required to synthesize one ATP molecule by oxidative phosphorylation?
3
what are 2 ROS molecules produced during electron transport
peroxide & superoxide
T or F: NADH & FADH2 cannot flow directly to O2, so they go through intermediate carriers
T
what is the electron transport chain & what happens
series of redox reactions where carriers become reduced by accepting electrons & then become oxidized as it passes electrons to next carrier
electrons flow to carriers with ( ) affinity for electrons
higher
what is the 1st electron transfer in the electron transport chain? and what does it produce?
NADH -> FMN, produces a proton gradient
how do electrons flow from NADH to O2?
through 3 complexes
how is FADH2 generated in the electron transport chain?
succinate q-reductase complex
T or F: iron is present in all complexes of electron transport chain
T
what are the 3 forms iron is present in?
1) Fe2+ - ferrous
2) Fe3+ - ferric
3) iron-sulfur
what are superoxide ions & how are they dangerous?
reduced O2 that interacts with DNA & causes damaged caused by ROS
what is ROS
reactive oxygen species
what 2 enzymes are used as defense against ROS?
superoxide mutase & catalase
what powers the synthesis of ATP
proton gradient
intermembrane space as ( ) concentrations & matrix has ( ) concentrations
high, low
chemiosmotic hypothesis
describes how ATP is produced via ATP synthase
proton motive force
force / energy used to synthesize ATP
ATP synthase is hypothesized to use a “binding change mechanism” which describes:
how the rotation of the γ-subunit of ATP synthase changes the conformation of the β-subunits, which facilitates ATP synthesis.
F0 vs F1
F0: embedded in inner mitochondrial membrane & contains proton channel
F1: catalytic activity
ATP synthase contains ( ) B subunits which each contains ( ) active site
3, 1
2,4-dinitrophenol increases metabolism by ( ) %
50%
what does 2,4-dinitrophenol act as?
protonphore
what is a protonphore?
molecule that inserts itself into inner mitochondrial membrane & allows protons to flow through it instead of through ATP synthase
how many ATP are produced from every NADH & FADH2 that enter electron transport chain
NADH- 2.5
FADH2-1.5
what is the net yield of ATP per glucose molecule oxidized & how many come from oxidative phosphorylation?
30 per glucose, 26 from oxidative phosphorylation
cellular respiration is ( ) when ADP levels are high = ( ) synthesis
high, ATP
( ) levels of ADP stimulate pyruvate dehydrogenase & isocitrate dehydrogenase
high
T or F: electrons do not flow through the electron transport chain to O2 unless there is a need for ATP synthesis
T
need for ATP synthesis when ADP levels are ( )
high
what are cytochromes
proteins that contain a heme & function in electron transfer
electrochemical gradient reflects what?
difference in solute concentration & charge across a membrane
what are the 3 conformations of B subunits?
O (open), L (loose), T (tight)
what does O conformation bind to?
ATP & adenine
what does L conformation bind to?
ADP & Pi
what does the T conformation convert?
converts ADP & Pi to ATP
glycerol 3-P shuttle function
NADH passes electrons to DHAP which becomes reduced to glycerol 3-P & allows entrance into intermediate space
malate-aspartate shuttle function
malate is oxidized to oxaloacetate & producs NADH which can enter electron transport chain
function of ATP-ADP translocase-brings ATP from where to where
brings ATP from mitochondrial matrix to cytosol & ADP from cytosol to mitochondrial membrane
what % of energy generated by electron transfer in respiratory chain is used to drive ATP-ADP exchange?
25%
