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