Electron Transport Chain

Question 1

What type of phosphorylation has to happen in order to phosphorylate ADP?

Answer 1

– Substrate-level phosphorylation

– Oxidative phosphorylation

Question 2

What is the Delta G required to produce ATP via Phosphorylation?

Answer 2

+ 7.3 kcal/mol

Question 3

ATP has a very ______ turnover rate

Answer 3

High

Question 4

What is the Electron Transport System?

Answer 4

• Mitochondrial mechanism that creates ATP by

passing electrons along a system of carriers

Question 5

Where does ETS take place?

Answer 5

Inner Mitochondrial membrane

Question 6

What is the source of Electrons in ETS?

Answer 6

macronutrient oxidation

Question 7

What is the ultimate acceptor of electrons in ETS?

Answer 7

Oxygen

Question 8

Is passing of electrons in ETS a favorable reaction?

Answer 8

Yes

Question 9

What is the proton gradient in ETS created by?

Answer 9

Passing the electrons

Question 10

What is ATP created by in ETS?

Answer 10

the proton gradient

Question 11

What is Oxidative Phosphorylation?

Answer 11

Electron transport system coupled with the

synthesis of ATP

Question 12

What are the characteristics of the Outer Mitochondrial membrane?

Answer 12

Porous, and permeable to most ions and small molecules

Question 13

What are the characteristics of the inner membrane of the mitochondria?

Answer 13

– Convoluted (increased surface area) (folds = cristae)
– Impermeable to most small ions and small molecules
• ATP, ADP, pyruvate, H+
, Na+
, K+ …
– Specialized carriers exist to transport these molecules
– Rich in integral proteins

Question 14

What is the composition of the mitochondrial matrix?

Answer 14

Water full of protein/enzymes “gel-like”

Question 15

What enzymes are found in the mitochondrial matrix?

Answer 15

• Pyruvate Dehydrogenase
• Isocitrate, α-ketoglutarate, succinate, and malate dehydrogenases
• β oxidation dehydrogenases (fat oxidation)
• Amino acid dehydrogenases (protein oxidation)

Question 16

What does the mitochondrial matrix contain large quanities of?

Answer 16

– NAD+ and FAD (oxidized form, required e- acceptors)

– ADP and Pi

Question 17

What are the final products of the aerobic metabolism of macronutrients?

Answer 17

CO2 + H2O + ATP

Question 18

What is NAD+ reduced by ?

Answer 18

dehydrogenases

Question 19

What does the reduction of NAD+ do?

Answer 19

This removes 2 hydrogen atoms from a
substrate (think Krebs cycle reactions)
– One hydrogen is removed with 2 e
- as a
hydride ion (H-
) while the other is removed as
the positive ion (H+
)

Question 20

How many complexes does the ETS chain have?

Answer 20

Five protein complexes

Question 21

What does Complex I (NADH Dehydrogenase) contain?

Answer 21

– Protein (Iron-Sulfur (FeS) complexes)

Question 22

What does Complex I do?

Answer 22

Utilizes FeS to Accept electrons from NADH and then Transfers electrons to ubiquinone (CoQ)

It contains a proton pump

Question 23

What is the proper equation for Complex I processes?

Answer 23

NADH+ + CoQ + 5H+
matrix → NAD+ + CoQH2 + 4H+
intermembrane space

Question 24

What does complex 2 (Succinate dehydrogenase) do?

Answer 24

• Oxidizes succinate and makes it fumarate

* Gives electrons to FAD creating FADH2

Question 25

Is there a proton pump in Complex 2?

Answer 25

No therefore no energy is lost

Question 26

What is Coenzyme Q?

Answer 26

Ubiquinone (not a protein)

Question 27

What does Coenzyme Q do?

Answer 27

Accepts electrons from FMNH2 or FADH2

Antioxidant

Question 28

Where does FMNH2 come from?

Answer 28

NADH dehydrogenase

Question 29

FADH2 is also a donor of ______ to CoQ

Answer 29

Electrons

Question 30

What are the complexes that are cytochrome proteins?

Answer 30

3, cytochrome C, and 4