7.5 The Electron Transport Chain and Oxidative Phosphorylation Flashcards
the complete oxidation of glucose during the first three stages of cellular respiration results in the production of:
two kinds of reduced electron carriers: NADH and FADH2
the energy in electron carriers is released in a series of:
redox reactions that occur as electrons pass through a chain of protein complexes in the inner mitochondrial membrane to the final electron acceptor, oxygen, which is reduced to water
the passage of electrons is coupled to the transfer of protons across the inner mitochondrial membrane creating:
a concentration and charge gradient: this electrochemical gradient provides a source of potential energy that is used to drive the synthesis of ATP
the inner mitochondrial membrane is:
selectively permeable (Protons can’t passively diffuse across, other molecules’ movement controlled by transporters and channels)
what are the two components of a proton gradient?
chemical-difference in concentration, electrical-difference in charge =e electrochemical gradient
the proton gradient is a source of:
potential energy
ATP synthase
an enzyme that couples the movement of protons through the enzyme with the synthesis of ATP
the gradient of protons provides a source of potential energy that is converted into:
chemical energy stored in ATP
chemiosmotic hypothesis
the hypothesis that the gradient of protons across a membrane provides a source of potential energy that is converted into chemical energy stored in ATP
where do electrons enter the electron transport chain?
at complex I (NADH) or complex II (FADH2)
the transport of electrons in complex I, III, and IV is coupled with:
the transport of protons across the inner membrane, from the mitochondrial matrix to the intermembrane space
within each protein complex of the electron transport chain, electrons are passed from:
electron donors to electron acceptors
each electron donor and acceptor is a:
redox couple, consisting of an oxidized and a reduced form of a molecule
the final reduction of oxygen to water is catalyzed by which complex?
complex IV
coenzyme Q (CoQ) AKA ubiquinone (hydrophobic)
in respiration, a mobile electron acceptor that transports electrons from complies I and II to complex III in the electron transport chain and moves protons from the mitochondrial matrix to the intermembrane space
once two electrons and two protons are transferred to CoQ, it forms:
CoQH2
cytochrome c (hydrophilic)
the enzyme to which electrons are transferred in complex III of the electron transport chain
once electrons are transferred from CoQH2 to cytochrome c, what happens to the protons?
they are released into the intermembrane space
the electron transfer steps are associated with the release of energy as electrons are passed from the reduced electron carriers (NADH, FADH2) to the final electron acceptor O2
some of the energy is used to reduce the next carrier, some used to pump protons across the inner mitochondrial membrane
the result of transfer of electrons being coupled with the pumping of protons is an:
accumulation of protons in the intermembrane space
where are protons in higher concentration?
in the intermembrane space, low concentration in the mitochondrial matrix. protons can’t diffuse into matrix because membrane blocks it, the gradient stores potential energy
the oxidation of the electron carriers NADH and FADH2 which formed during glycolysis, pyruvate oxidation, and the citric acid cycle leads to:
the generation of a proton electrochemical gradient (a source of potential energy) which is used to synthesize ATP
the ATP synthase enzyme is composed of two distinct subunits called:
F0 and F1
Fo forms the:
inner mitochondrial membrane
channel in the inner mitochondrial membrane through which protons flow, rotates as protons pass through
F1 is the :
mitochondrial matrix
catalytic unit that synthesizes ATP, uses rotational energy of Fo to synthesize ATP
proton flow through the Fo channel causes it to rotate, converting the energy of the proton gradient into:
mechanical rotational energy (kinetic energy), leads to the rotation of the F1 subunit in the mitochondrial matrix
the rotation of the F1 subunit causes:
conformational changes that allow it to catalyze the synthesis of ATP from ADP and Pi, converting mechanical energy into the chemical energy of ATP
what are sufficient components to produce ATP?
a membrane, proton gradient, and ATP synthase
for each molecule of NADH that donates electrons, how many ATP are produced?
2.5 molecules
for each molecule of FADH2 that donates electrons, how many ATP are produced?
1.5 molecules
overall, the complete oxidation of glucose yields how many ATP?
32
