8: The Electron Transport Chain & Oxidative Phosphorylation

The three stages of cellular respiration are ________.

Acetyl CoA synthesis, citric acid cycle, and oxidative phosphorylation (electron transfer & ATP synthesis).

The typical person expends about 2000 kcal per day = _____ kg ATP.

83kg, about 60 g per minute

Each ATP molecule is recycled about _____ times per day.

3000

_________ is the process that uses energy released by the oxidation of nutrients to produce ATP from ADP and Pi.

Oxidative phosphorylation

Oxidative phosphorylation is used by __________.

All forms of life (nutrients may differ)

ATP is synthesized as electrons from _________ passed from electron donors to electron acceptors in the inner mitochondrial membrane. ("electron transfer/transport chain")

NADH/FADH2

Energy is released during electron transport, which drives _____ synthesis.

ATP

The initial electron donors are _______.

NADH and FADH2

The final electron acceptor is _____.

O2 -> H2O

Mitochondria contain enzymes of the _______.

Citric acid cycle

Mitochondria contain enzymes for _________.

Oxidative phosphorylation

The mitochondrial outer membrane is ______ to small molecules/ions.

Permeable

The mitochondrial inner membrane is _______ to small molecules/ions.

Impermeable (requires specific transporters)

Oxidative phosphorylation is carried out by a series of _______ at the inner mitochondrial membrane.

Protein complexes

There are two entrance points into the cycle, _____ and _____.

Complex 1 (NADH) and complex 2 (FADH2)

As electrons flow through the electron transport chain through a series of ___________ reactions, energy is released.

Oxidation/reduction

Released energy is used to transport protons across the ______ mitochondrial membrane into the intermembrane space.

Inner

Protons flow back across the membrane and down the electrochemical gradient, through an enzyme called _________.

ATP synthase

ATP synthase generates ATP from _______.

ADP and Pi

Electron transport requires electron ___________.

Carriers

Electrons are transported within large protein complexes via ______________.

A series of oxidation/reduction reactions

Electrons are transported from one large protein complex to another via ________.

Electron carriers

______ is a lipid soluble electron carrier that likes to interact with other lipids (not water). It's job is to deliver electrons between less mobile e-carriers in a membrane. It can exist in different states, oxidized or reduced.

Coenzyme Q/Ubiquinone

Proteins that function as electron carriers are called ______.

Cytochromes

Cytochrome c is a soluble protein that carries _______.

One electron

______ is the prosthetic group of cytochromes, which carry the electrons.

Heme

_____ is present in the heme ring in an oxidized or reduced state.

Iron

Electron are passed by the reduction of Fe3+ to _______.

Fe2+, and back to Fe3+

_______ are 2 iron atoms joined by 2 atoms of an inorganic sulfur.

Iron sulfur centers

Iron sulfur centers are linked to a protein by the amino acid ________.

Cysteine

One protein can have ____ iron-sulfur centers.

Several

Copper sulfur centers work _________ iron.

The same way as

Complex 1 is _______.

NADH dehydrogenase

Complex 1 is the _____ entry point of the electron transport chain.

1st

Complex 1 has _____ iron-sulfur centers.

Several

Complex 1 is _____ shaped.

L (one arm in the matrix, one in the membrane)

Complex 2 is ________.

Succinate dehydrogenase

Complex 2 is the _____ entry point of the electron transport chain.

2nd

The CAC oxidizes succinate to ____.

Fumarate

Complex 3 is ________.

Cytochrome C oxidoreductase

Complex 3 is present in the_____________.

Inner mitochondrial membrane

Complex 3 transfers electrons from QH2 to _____.

Cytochrome C

Complex 3 uses _______ centers.

Heme and Iron sulfur

Complex 3 transports ____ protons from matrix to intermembrane space, which contributes to the proton gradient.

4

Complex 4 is _____________.

Cytochrome C oxidase

Complex 4 is the ________ in the electron transport chain

Final protein complex

Complex 4 accepts electrons from ________.

Cytochrome C

In complex 4, the final electron acceptor is ____.

O2

Complex 4 reduces 02 to ____.

Water

Complex 4 pumps ___ H+ across the membrane per electron pair.

2

Movement of protons during electron transfer creates __________ across the membrane.

an electrochemical gradient

Energy from electron transfer is conserved in the electrochemical gradient as the _________.

Proton motive force

The flow of protons down their electrochemical gradient (i.e., back into mitochondria) provides the necessary energy for _______.

ATP synthesis (ATP synthase)