Lecture 5 Flashcards
What are the parts of ATP synthase?
F1 and F0. F1 has the alpha, beta alternating subunits whilst F0 has the a, b, and c subunits.
How many beta subunits are there? How many degrees do they rotate?
There are 3 beta subunits. They rotate 120°.
How many protons does Complex I pump to the IMS?
4 protons
How many protons does Complex III pump to the IMS?
4 protons
How many protons does Complex IV pump to the IMS?
2 protons
How many protons are pumped to the IMS for each NADH? What about each FADH2?
10 protons per NADH
6 protons per FADH2 (The 4 protons from Complex I are bypassed)
For a c ring with 12 subunits, how many protons are pumped per ATP?
12 + 3 = 15 protons
15 protons/3 ATP
Answer: 5 protons/ATP
In what ways is the “D pathway” critical for 2 major processes that happen at Complex IV?
- The Asp carboxylate ion binds protons from the matrix and moves them to the IMS (2 protons are moved)
- It supplies 2 protons for reducing oxygen to water
What are the 2 translocases for transporting ATP, ADP, H2PO4, and H+ called? Are they anti porters or symporters?
Adenine nucleotide translocase
Phosphate translocase
Describe adenine translocase
It imports 3 ADP for every 4 ATP it exports. The net charge ends up being negative because…
Describe the role of phosphate translocase
It transports both phosphate and protons from the IMS into the matrix. This movement consumes some of the energy from electron transfer.
Where is the malate-aspartate shuttle located in the body?
Liver, kidneys, and heart
Where is the glycerol 3-phosphate shuttle found in the body?
Skeletal muscle and brain
Describe the major transporters in the malate-aspartate shuttle
The malate alpha ketoglutarate transporter brings malate into the matrix, where malate gives 2 reducing equivalents to NAD+ to generate NADH
The Glu-Asp shuttle transports aspartate from the matrix out to the IMS, where the cycle repeats
Describe what goes on in the glycerol 3-P shuttle
NADH gives 2 reducing equivalents to DHAP, turning it into glycerol 3-P. Mitochondrial glycerol 3-P DH takes 2 protons and gives them to Q, which reduces to QH2. QH2 then goes on to Complex III.
