How do liver and heart cells transport NADHs from glycolysis into the mit matrix and why do these still produce the full 2.5 ATPs?

How do liver and heart cells transport NADHs from glycolysis into the mit matrix and why do these still produce the full 2.5 ATPs?

Answer:


How---by way of the malate aspartate shuttle
Why--higher energy requirements

In the aldol cleavage of Fructose 1,6 bis phosphate to DHAP and GAP, why is there 96% DHAP?

In the aldol cleavage of Fructose 1,6 bis phosphate to DHAP and GAP, why is there 96% DHAP?

Answer: Because DHAP is involved in the uptake of glycolysis NADH electrons into the mitochondrial matrix so they can also be used in ATP production. BUT these are taken up by FADH molecules and so become worth only 1.5 ATP (unlike Krebs Cycle NADHs)

Why does the c ring rotate?

Why does the c ring rotate?

Answer: Each c subunit has a critical aspartic acid residue that when an H+ comes in, causes it to become neutralized and thus want to interact with the hydrophobic membrane. Thus it pulls that c cubunit to the side. This is repeated over and over again. And as the C ring turns it causes the gamma to rotate

Describe how ATP hydrolysis (the reverse reaction) can be visualized.

Describe how ATP hydrolysis (the reverse reaction) can be visualized.

Answer: Attachment of an actin filament to the rotating gamma subunit allows for visualization of the rotation (actin will be seen as rotating).

Describe how the gamma and beta subunits of ATP synthase interact to allow ATP formation.

Describe how the gamma and beta subunits of ATP synthase interact to allow ATP formation.

Answer: The gamma subunit as it rotates extends into the ring and breaks the symmetry of the hexamer by interacting with a beta subunit and changing the beta subunits conformation. The change in conformation causes the beta subunit to either be in a an open, tight or loose position. ATP is generated from ADP and Pi in the tight conformation and released in the loose conformation.

Describe the structure of ATP synthase.

Describe the structure of ATP synthase.

Answer: Draw and label it

Describe the experiment used to test the proton-motive force. Draw it.

Describe the experiment used to test the proton-motive force. Draw it.

Answer: Used light sensitive bacteriorhodopsin protein incorporated on one end of a vesicle membrane, ATP synthase on the other. The protein is closed when in the dark. Put a high concentration on H+ ions and ADP + Pi outside the vesicle. Then shine light on the vesicle. They found that the ATP was produced. So the proton motive force is coupled with ATP synthesis.

Describe the action on Complex IV.

Describe the action on Complex IV.

Answer: Cytochrome C Oxidase catalyzes the transfer of electrons from 4 reduced Cyt C molecules to Oxygen. The electrons first reduce Heme a3 and Cub which then bind to oxygen. The oygen will take the electrons from them to form H2O.

Describe how Complex III makes QH2 give up its protons.

Describe how Complex III makes QH2 give up its protons.

Answer: Complex III is Q-cytochrome C oxidoreductase.

What is ubiquinone versus ubiquinol?

What is ubiquinone versus ubiquinol?

Answer:

Ubiquinone is the oxidized form of Coenzyme Q (Q)
Ubiquinol is the reduced form of Coenzyme Q (QH2)

Why does each NADH give 2.5 ATPs but each FADH2 only gives 1.5.

Why does each NADH give 2.5 ATPs but each FADH2 only gives 1.5.

Answer: When FADH2 is taken up by Complex II, it undergoes the same transfer of electrons through iron-clusters and then to Coenzyme Q, and QH2 is formed however, this is all not coupled to a pumping of protons out at this point. (It is only involved in the Q protons while NADH is involved in the Q protons AND the pump at Complex I)

What are the two special things about Complex II.

What are the two special things about Complex II.

Answer: It is the same succinate dehydrogenase from the Krebs cycle. Was the only Krebs Cycle enzyme that was embedded into the mitochondrial matrix. Second special thing--this is where FADH2 enters the electron transport chain.

Describe the flow of NADH's electrons.

Describe the flow of NADH's electrons.

Answer: NADH gives two electrons to FMN, the electrons then travel through a series of iron-sulfur clusters to get to Coenzyme Q. Coenzyme Q accepts the two electrons (and in the process also takes up 2 protons from the matrix to become QH2). All this flow of electrons from NADH to Coenzyme Q is coupled to the pumping of 4 protons out.

Describe the structure of Complex I.

Describe the structure of Complex I.

Answer: It is a Huge complex with 46 subunits. Its structure suggests a piston mechanism that shunts protons across the membrane through 3 separate channels.

What is the respirasome?

What is the respirasome?

Answer: These are Complexes I, II, III, IV that sit on the mitochondrial inner membrane and are involved in the pumping of H+ ions into the intermembrane space