Chemiosmosis
What causes the "rotor" of ATP synthase to start spinning?
protons move into the binding sites on one of the "parts"
In ATP synthase, the flow of _____ behaves somewhat like a rushing stream that turns a waterwheel---the ______.
protons; the "rotor" of ATP synthase
What is the smallest molecular rotary motor known in nature?
ATP synthase
At complex I, III, and IV, an ____ is pumped out into the inter membrane space.
H+
In general terms, chemiosmosis is an energy-coupling mechanism that uses energy stored in the form of an ____ across a membrane to drive _____.
H+ gradient --->drives cellular work
Some members of the ETC accept and release ____ along with electrons.
H+ protons
What does ATP synthase do?
Makes ATP from ADP/inorganic phosphate
What is chemiosmosis?
process in which energy stored in an H+ ion gradient across a membrane is used to drive cellular work (ATP synthesis)
What is the "power source" for ATP synthase?
a difference in the H+ concentration on opposite sides of the inner mitochondrial membrane (difference in pH)
The energy stored in an H+ gradient couples the redox reactions of ETC to ATP synthesis. This is an example of _____.
chemiosmosis
H+ has a tendency to move back across the membrane, diffusing (down/against) its gradient.
down
Where does the proton motive force drive H+ to? How does the H+ get there?
drives H+ back across the membrane via H+ channels provided by ATP synthases
How does the mitchondria maintain the H+ gradient?
establishing the H+ gradient is a major function of the ETC
The ETC is an energy converter that uses the (exergonic/endergonic) flow of electrons from NADH and FADH to pump H+ across the membrane.
exergonic
The flow of H+ from the mitochondrial matrix to inter- membrane space is (exergonic/endergonic).
exergonic
The phosphorylation of ADP to ATP is (exergonic/endergonic).
exergonic
What does the spinning of the ATP synthase "rotor" do?
it catalyzes ATP production from ADP/inorganic phosphates
Why does FADH result in fewer protons being pumped into the inter membrane space than in NADH?
it deposits its electrons in complex II instead of complex I
Both mitochondria and chloroplasts perform chemiosmosis. However, their source of energy differs. Mitochondria's energy source is _____, while chloroplasts energy source is ______.
mitochondria = chemical energy chloroplasts = light energy
H+ is accepted from the ______ and deposited in the _____. The H+ gradient that results from this moment is referred to as a ______.
mitochondrial matrix-->inter membrane space; proton-motive force
What is the structure of ATP synthase?
multi-subunit complex (4 parts, each made of polypeptides)
Under conditions of cellular respiration, ATP synthase uses the energy of an existing ion gradient to ______.
power ATP synthesis
What does the proton-motive force emphasize?
the ability for the H+ gradient to do work
What does "osmosis" refer to in chemiosmosis?
the flow of H+ across a membrane
True/false: ATP synthase are the only sites that provide a route through the membrane for H+.
true