Electron Transport chain

Question 1

Purpose

Answer 1

NADH electrons from glycolysis enter mitochondria from glycolysis enter mitochondria via the Malate- aspartate or the glycerol 3 phosphate shuttle. FADH2 electrons are transferred to complex 3 (at a lower energy level than NADH) passage of the electrons creates a proton gradient that when coupled to oxidative phosphorylation drives the production of ATP

Question 2

Why perform Aerobic respiration

Answer 2

Glycolysis is inefficient bc it produces 20x less ATP per mole of glucose than oxidative phosphorylation

Oxidative phosphorylation produces 36 ATP/glucose

Question 3

Why perform Aerobic respiration

Answer 3

Glycolysis is inefficient bc it produces 20x less ATP per mole of glucose than oxidative phosphorylation

Oxidative phosphorylation produces 36 ATP/glucose

Question 4

Chemostatic theory

Answer 4

ATPase that pumps H inside a vesicle with the cleavage of ADP–> ATP outside of the vesicle, at a certain point you will stop pumping in H when ATP and ADP levels are equal

If you add a pump that just continuously pumps H inside the vesicle, then the ATPase will continue to make convert ADP to ATP

The pumping of H and The making of ATP are tightly coupled so that if you dont pump H you dont make ATP

Question 5

What things are required for a proton circuit

Answer 5

Impremeable membrane

e carriers

Proton pumps

ATPase

Question 6

The impermeable membrane

Answer 6

the MIM (mitochondrial inner membrane)
Has an unusual lipid concentration with low sterol and high cardiolipin
It is mostly 60-70% proteins

Question 7

The electron carriers

Answer 7

Ubiquinone (Coenzyme Q or CoQ)
Flavoproteins with tighlty bound FAD/ FMN
Cytochromes A B and C
Fe/S proteins
Protein bound Cu

Mobile carriers (CoQ and cyt C)

The electrons flow down a thermodynamic path thats favorable and that work (movement) is captured by H pumping from matrix to the IMS (inner membrane space)

Question 8

The proton pumps

Answer 8

Complex 1-4

Question 9

Complex 1

Answer 9

converts NADH-> NAD + H + 2 e- in matrix side

Pumps 4 protons in matrix

Takes the E and puts it on Ub

Ub-E carries the E to Complex 3

Question 10

Complex 3

Answer 10

pumps 4 protons into IMS

and sends E to cyt C (one at a time)

Question 11

Complex 4

Answer 11

cytochrome C brings its E to complex4

oxygen gets reduced to h2o by complex4

2 protons are consumed in the process so a net of 2 protons get pumped into the IMS

Question 12

Complex 5

Answer 12

ATP synthase, that converts the ADP to ATP
via coupling to complex 4

And pumps ATP to the Matrix

Question 13

Complex 2

Answer 13

succinyl dehydrogenase
Converts FADH2 to FAD
Adds Electrons to the Ubq pool
electrons are shuttled to complex 3

Question 14

What contributes to electrons flowing to the UbQ/ COQ pool

Answer 14

B oxidation, glycolysis, pyrimidine synthesis

Question 15

Mito DNA diseases associated with E transport chain

Answer 15

Complex 2 has strictly nuclear DNA, the rest have a mix

1, 2, 3, 4 Leighs Syndrome
1 = LHON, MELAS
3= Cardiomyopathy
4= ALS like syndrome

Question 16

Electron transport pump inhibitors

Answer 16

Rotenone: complex 1 inhibitor

Antymycin A: complex 3 inhibitor

IDES, Cyanide, carbon monoxide, azide inhibit complex 4

Question 17

MIM (mitochondrial inner membrane is impermeable so how do things cross into the matrix?

Answer 17

Carriers/ transporters that are specific for substrates
ATP-ADP translocase= pumps ATP out and ADP in, it does so in a concentration dependent manner

NADH cannot get Through the membrane, which poses a problem because you need its electrons

Question 18

Malate aspartate shuttle

Answer 18

Cytosolic NADH (from glycolysis) does not enter the mito matrix but the 2 e of NADH ride on Malate which can go thru malate

When malate is inside the matrix its converted into OAA and in the process releases NADH

glutamate and OAA are converted into aspartate and aKG which can both leave the mito and are transfered back into OAA and gluamate in the cyto

Question 19

Glycerol phosphate shuttle

Answer 19

irreversible and makes FADH2 and COQ rather than NADH and is very active in Muscle and Brain