Biochemistry 2280A Study Guide - Midterm Guide: Atp Synthase, Electrochemical Gradient, Chemiosmosis
Biochemistry 2280 – Midterm
ATP Synthesis
Summarize how energy flows from reduced electron carriers to ATP in the process of oxidative
phosphorylation
- the electron transport chain pumps protons out of the matrix, creating a proton gradient
which then drives the synthesis of ATP
Explain the chemiosmotic hypothesis
- protonmotive force drives the synthesis of ATP
• shown on the right (arrows differ in how strong the force is)
• two components; concentration gradient and electrical potential
• overall electrochemical gradient is going to combine both
• about a 7-fold difference in pH between the intermembrane space and the matrix
- explains why destruction of the proton gradient inhibits ATP synthesis
- also, if you can make an artificial gradient, you can also make ATP
Explain the mechanism of ATP synthase, including the role of each subunit of the
E.coli enzyme
F1F0 ATP Synthase
• protein complex that allows proteins to flow down their electrochemical
gradient
• the energy from this proton movement is used to make ATP
• it is embedded in the intermitochondrial membrane
• the protons bind to the lue thing (on particular side chains) and then go almost all
the way around it, and then out at the bottom
• as the blue thing rotates, the green piece stays where it is
• the dark blue piece (the shaft) is not symmetrical; it rotates with the light blue piece,
and the part that is sticking out bumps different things
• this makes the alpha and beta sections bounce around, and that is how ATP is made
from ADP and Pi (3 per rotation)
• this can all also happen in the reverse direction
F0 (e. coli)
• 3 subunits: ab2c10
• proton channel
• transmembrane
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Document Summary
Summarize how energy flows from reduced electron carriers to atp in the process of oxidative phosphorylation. The electron transport chain pumps protons out of the matrix, creating a proton gradient which then drives the synthesis of atp. Explains why destruction of the proton gradient inhibits atp synthesis. Also, if you can make an artificial gradient, you can also make atp. Explain the mechanism of atp synthase, including the role of each subunit of the. F1 (e. coli: 5 subunits: 3 3(cid:630)(cid:631)(cid:632, makes atp, peripheral, 3 3 form active sites (one on each ); conformational changes cause atp synthesis, (cid:630) forms part of central stalk; rotates with c10 to cause conformational changes in. 3 3: (cid:631) helps attach b2 to 3 3, (cid:632) helps assemble complex; inhibits atp hydrolysis. State the number of protons that move across the inner mitochondrial membrane to synthesize and export one atp molecule, and justify that number.