Electron Transport Chain

Question 1

Incomplete oxidation in ketogenesis results in?

Answer 1

incomplete oxidation of fatty acids resulting in less energy

Question 2

Anything produced in the cytoplasm is transported to?

Answer 2

the mitochondrial matrix

Question 3

What is the role of NADH and FADH2 in the electron transport chain?

Answer 3

The NADH and FADH2 give up their electrons to reduce molecular O2 to H2O.

Question 4

ETC takes place in _______ where all of the electron carriers are present.

Answer 4

inner mitochondrial membrane

Question 5

What is the function of the electron transport chain?

Answer 5

The function of ETC is to facilitate the controlled release of free energy that was stored in reduced cofactors during catabolism.

Question 6

What plays a critical role in forming and utilizing the proton gradient to synthesize ATP?

Answer 6

mitochondrial structure

Question 7

Where in the mitochondria is ATP synthesized?

Answer 7

matrix

Question 8

When is energy released?

Answer 8

when electrons are transported from higher energy NADH/FADH2 to lower energy O2

Question 9

The coupling of ATP synthesis to NADH/FADH2 oxidation is called?

Answer 9

oxidative phosphorylation

Question 10

______ is responsible for 90% of total ATP synthesis in the cell.

Answer 10

oxidative phosphorylation

Question 11

The oxidized compound [loses/gains] electrons.

Answer 11

loses

Question 12

The reduced compound [loses/gains] electrons.

Answer 12

gains

Question 13

What acts as a mechanism for storing energy?

Answer 13

reduction

Question 14

The electron transport chain is in which part of the mitochondria?

Answer 14

in the cristae (the folded inner membrane) of the mitochondrion

Question 15

Most of the electron transport chain’s components are?

Answer 15

proteins

Question 16

A _______ and a _______ shuttle between protein complexes.

Answer 16

lipid soluble coenzyme (Q); water soluble protein (cyt c)

Question 17

How does the ETC work?

Answer 17

Electrons drop in free energy as they go down the chain and are finally passed to O2, forming H2O.

Question 18

ATP synthesis (phosphorylation) must be coupled to?

Answer 18

to the generation of a H+ reservoir/pH gradient (oxidation) between the mitochondrial membranes

Question 19

Every 4 H would constitute _____ ATP.

Answer 19

1

Question 20

When electrons are transported along the components of the ETC, what happens to the accompanying protons?

Answer 20

they are released

Question 21

Part of the free energy harvested during the ETC is used to?

Answer 21

to pump protons out of the mitochondrial matrix

Question 22

The resulting uneven distribution of protons generates?

Answer 22

a pH gradient and a charge gradient across the inner mitochondrial membrane

Question 23

The electrochemical potential energy generated by the pH and charge gradients is called _________.

Answer 23

Proton Motive Force

Question 24

The return of protons to the mitochondrial matrix is coupled to?

Answer 24

ATP synthesis

Question 25

Most drugs interfere with complex 4 which gives what effects?

Answer 25

side effect, carbon monoxide, cyanide which can kill because it blocks the ETC and results in no energy

Question 26

Electrons move from a carrier with [low/high] reduction potential toward carriers with [lower/higher] reduction potential.

Answer 26

low, higher

Question 27

What is the only enzyme in the Citric Acid Cycle that is membrane bound? (bound to inner mitochondrial membrane)

Answer 27

succinate dehydrogenase

Question 28

Cytochrome Oxidase is directly linked to?

Answer 28

Complex 4

Question 29

_________ and ________ are affected during apoptosis in pesticides

Answer 29

ubiquinone, cyt c

Question 30

Briefly explain the chemiosmotic hypothesis

Answer 30

Basically coupling electron flow through the ETC to ATP synthesis

Question 31

The respiratory complexes are _________.

Answer 31

proton pumps

Question 32

As electrons pass through complexes _________, hydrogen ions are pumped across the inner mitochondrial membrane into the intermembrane space

Answer 32

I, III, and IV

Question 33

The proton concentration in the intermembrane space [decreases/increases] relative to the mitochondrial matrix

Answer 33

increases

Question 34

The proton-motive force is generated as a result of which two factos?

Answer 34

1) Difference in pH and 2) Difference in electrical potential, delta si, between intermembrane space and the mitochondrial matrix.

Question 35

What is complex V?

Answer 35

ATP synthetase complex

Question 36

ATP synthesized in the matrix is transported out of the matrix via an ___________ (an antiport) also coupled to proton motive force

Answer 36

ATP/ADP translocase

Question 37

What is the malate-aspartate shuttle?

Answer 37

a biochemical system for translocating electrons produced during glycolysis across the semipermeable inner membrane of the mitochondrion for oxidative phosphorylation in eukaryotes

Question 38

What is the glycerol-3-phosphate shuttle?

Answer 38

a mechanism that regenerates NAD+ from NADH, a by-product of glycolysis. Its importance in transporting reducing equivalents is secondary to the malate-aspartate shuttle

Question 39

Why do we need the malate-aspartate shuttle?

Answer 39

to shuttle NADH to the mitochondrial matrix

Question 40

What does dinitrophenol do?

Answer 40

Dinitrophenol uncouples proton motive force and ATP synthesis

Question 41

_______ is the molecular motor of life.

Answer 41

ATP synthase complex

Question 42

What is done to protect vital organs during animal hibernation?

Answer 42

uncoupling proteins which generates metabolic heat

Question 43

ATP synthesis can be “uncoupled,” if the proton gradient is _______________.

Answer 43

prematurely dissipated or impeded

Question 44

What are involved in site complex I?

Answer 44

amytal & rotenone

Question 45

What is involved in site complex III?

Answer 45

antimycin A

Question 46

What is involved in site complex IV?

Answer 46

Cyanide (CN-), Sodium azide (N3-), CO

Question 47

What is amytal?

Answer 47

a type of barbiturate used in the treatment of severe sleeping disorders

Question 48

What is rotenone?

Answer 48

used as a broad-spectrum insecticide, piscicide, and pesticide

Question 49

What is antimycins?

Answer 49

active ingredient in Fintrol, a chemical piscicide (fish poison) used in fisheries management and in the catfish industry

Question 50

Mitochondrial DNA is [paternally/maternally] inherited.

Answer 50

maternally

Question 51

______ polypeptides required for oxidative phosphorylation are coded by ________.

Answer 51

13; mtDNA

Question 52

Defects in oxidative phosphorylation are a result of alterations in ________.

Answer 52

mtDNA

Question 53

Which tissues are affected by defects in oxidative phosphorylation?

Answer 53

CNS, Skeletal & heart muscles and Liver