Lecture 23 Oxidative Phosphorylation

Question 1

in the ETC where are you pumping protons to?

Answer 1

you are pumping protons from the matrix into the intermembrane space

Question 2

why are there so many folds of the intermembrane?

Answer 2

to maximize surface area to do the most ETC and ATP synthase as possibe

Question 3

Is e- transport requires for ATP synthesis?

Answer 3

no, if you maintain proton gradient, then your good.

Question 4

What is valinomycin?

Answer 4

an ionophore that can carry K+ through the membrane down its chemical gradient

Question 5

what does complex 5 do? in terms of proton gradient

Answer 5

uses the proton gradient produced by the ETC to move proteins down its concentration gradient from the intermembrane space back into the matrix to make ATP

Question 6

What is the “N” side of the membrane?

Answer 6

the matrix, which is the negative of the membrane

Question 7

What is the “P” side of the membrane?

Answer 7

the intermembrane space, which is Positive (bc you pumped all those protons over there)

Question 8

What is another name for atp synthase that’s not complex 5?

Answer 8

FoF1 ATPase
Fo (membrane soluble part) part refers to the potion of the complex that is inside of the membrane and
F1 refers to the (peripheral) part of the complex that is hanging out of the matrix side (F1 potion is dissociable and you can seperate the integral and peripheral portions)

Question 9

Peripheral part of ATPase

Answer 9

F1

Question 10

Integral part of ATPase

Answer 10

Fo

Question 11

which part of ATPase is responsible for dragging protons across the membrane?

Answer 11

F0

Question 12

What direction is ATP synthase rotation if its doing ATP hydrolysis?

Answer 12

Counter clockwise

Question 13

What direction is ATP synthase rotation if its synthesizing ATP?

Answer 13

Clockwise

Question 14

Does ATP synthase rotate differently depending on if its synthesizing of hydrolyzing ATP

Answer 14

yas queen I would just be doing the reverse reaction so it would just move backwards

Question 15

Why and how does Fo Rotate?

Answer 15

because you have a continuous sexy proton gradient each H+ that moves into F0 is met with an aspartic acid that get protonated by the H+, and as more H+ come, the deprotonated aspartic acids grab the protons causing the protonated apratice acids to move out of the way and rotate counter clockwise (this is talking about if you’re doing synthesis of course) kind of like a revolving door rat race situation

Question 16

Why is the F₀ portion of ATP synthase named “F₀”

Answer 16

named for its sensitivity to Oligomycin, an antibiotic that specifically stops ATP synthase by binding to the Fo which “puts a wrench in the revolving door” and keeps it from moving protons

Question 17

how many diffrent Alpha and beta dimers are there in the F1 portion of the ATPase

Answer 17

3, like a 6 petal flower

Question 18

Oligomycin

Answer 18

an antibiotic that binds to Fo part of ATPase and stops its form rotating and therefore stops it all together

Question 19

how many protons are needed for each synthesis of ATP

Answer 19

4

Question 20

does F1 act like a MM enzyme

Answer 20

No! bc the off rate (letting go of the fully formed ATP) is actually the rate limiting step (the slowest)

Question 21

what makes the alpha and beta subunits change conformation to either favor binding, catalysis or release ATP

Answer 21

the rotation of the gamma, epsilon and C (F0) portion of the synthase by the introduction of protons

Question 22

What is the ΔG (Gibbs free energy change) of moving a proton through ATP synthase (ATPase)

Answer 22

around -20 kj/mol

Question 23

Does shutting off the ETC shut off ATP ase

Answer 23

yes

Question 24

what do ETC uncouplers? examples? what characteristics do uncouplers have to have?

Answer 24

They uncomple the ETC and rip protons shutting off ATPase
-they can freely diffuse across membrane and carry H+ (they are a type of ionophore)
-they have to be hydrophobic
-they can be protonated

Question 25

What is DNP

Answer 25

A type of uncoupler (the diet thing)

Question 26

Why do you require ADP to start the ETC reduction of water?

Answer 26

Just because you need the ingredients to make ATP synthase to go and if you cant make ATP synthase go then you lock the whole ETC in place

Question 27

What is the uncompler that helps animals hibernate

Answer 27

Thermogenin (an uncoupling protein)

Question 28

What does the C complex do in ATPase

Answer 28

pumps protons and rotates

Question 28

technically 3 protons are needed to make an ATP, why do you need the 4th?

Answer 28

To move the inorganic Phosphate into the intermembrane space

Question 29

Where does glycolysis happen?

Answer 29

in the cytoplasm

Question 30

Why do you need an NADH shuttle?

Answer 30

bc there is lots of NADH in cytoplasm that cant be used for ETC unless you get it into the matrix

Question 31

Pathway NADH of muscle and brain Dihydroxyacetone phosphate G3P shuttle

Answer 31

1. cytoplasm- using NADH reduce DHAP to G3P which is able to permeate the outer membrane 2. intermembrane space- oxidize G3P back into DHAP (where it goes on its merry way) using G3P dehydrogenase that reduces FADH2 so that its in the inner membrane and able to directly go into complex 3 as that FADH2

Question 32

what part of the body does the NADH Dihydroxyacetone phosphate. G3P shuttle happen

Answer 32

Muscles and brain

Question 33

what energy consequence does the NADH Dihydroxyacetone phosphate G3P shuttle and why is it okay

Answer 33

reduces overall net ATP by 2 because you're going into ETC as FADH2 instads of NADH but its chill bc your brain and muscles need so much energy it will take the hit

Question 34

What part of the body does the Malate- Aspartate shuttle happen in, and is there an energy consequence?

Answer 34

liver, heart, kidney, NO

Question 35

Steps in the malate- aspartate shuttle

Answer 35

1. (in intermembrane space) Reduce oxaloacetate using NADH and turn it into Malate 2. the malate has a transporter for itself (she's special) 3. once in the matrix you just oxidize that maleate to get your NADH out back into oxaloacetate 4. But how do you get you oxaloacetate back out???(there are no shuttle for her) 5. you do a side reaction that turns that ho into an aspartate (by aminotransferase IE transamination using glutamate and alpha ketoglutarate) where its then able go through a transporter and then tranaminate it again once its in the IM space back to oxaloacetate where its able to shuttle again!!!!

Question 36

which is more efficent DHAP or aspartate malate

Answer 36

DHAP is faster but has -2 aura aspartate malate is slower but nothing is lost