21 electron transport

A collection of vocabulary flashcards focused on key terms and concepts related to the electron transport chain in biochemistry.

Electron Transport Chain (ETC)

A series of protein complexes and other molecules that transfer electrons from electron donors to electron acceptors through redox reactions.

NADH

A main electron carrier that stores energy used in the electron transport chain.

FADH2

Another important electron carrier that transfers electrons to the electron transport chain.

Redox reactions

Reactions involving the transfer of electrons between two species.

Proton gradient

The difference in proton concentration across the mitochondrial membrane, which drives ATP synthesis.

ATP Synthase

An enzyme that uses the proton gradient to convert ADP and inorganic phosphate into ATP.

Complex I

The first multi-subunit complex in the electron transport chain that transfers electrons from NADH to coenzyme Q.

Complex II

A multi-subunit complex that transfers electrons from succinate to coenzyme Q using FAD.

Complex III

A complex comprising 11 subunits that transfers electrons from coenzyme Q to cytochrome c.

Complex IV

Cytochrome c oxidase, which transfers electrons from cytochrome c to oxygen.

Ubiquinone (Coenzyme Q)

A lipid-soluble electron carrier that can carry one or two electrons.

Standard reduction potential (E°)

A measure of the tendency of a chemical species to acquire electrons and be reduced.

Oxidative phosphorylation

The process of generating ATP from the transfer of electrons through the electron transport chain.

Flavin adenine dinucleotide (FAD)

An important electron carrier that participates in redox reactions in the electron transport chain.

Cytochrome c

A soluble electron carrier that moves electrons between complex III and complex IV.

Iron-sulfur clusters

Metal clusters that can transfer single electrons in the electron transport chain.

Reduction potential (E°′)

The potential at which a half-reaction occurs, standardized at a pH of 7.

Delta G (ΔG)

The Gibbs free energy change of a reaction, indicating the spontaneity of the reaction.

Hydride transfer

The transfer of a proton and two electrons to a recipient molecule in redox reactions.

Proton translocation

The movement of protons across the mitochondrial membrane, creating a proton gradient.

Q Cycle

A process in complex III that allows for the transfer of electrons from ubiquinol to cytochrome c.

Half-cell

A system in electrochemistry consisting of an electrode in a solution of its ions.

Electrochemical gradient

A difference in charge and chemical concentration across a membrane.

Antimycin A

A drug that inhibits complex III of the electron transport chain.

Rotenone

A pesticide that inhibits electron transfer from complex I to coenzyme Q.

Cytoplasmic side

The side of the mitochondrial membrane that faces the cytoplasm.

Matrix

The area within the inner mitochondrial membrane where important metabolic events occur.

Proton-motive force

The force generated by the proton gradient across the membrane that drives ATP synthesis.

Reduction

The gain of electrons by a molecule or atom.

Oxidation

The loss of electrons by a molecule or atom.

Eukaryotic cells

Cells that have a nucleus enclosed within membranes, such as those in animals and plants.

Mitochondrial membrane

The double membrane structure surrounding the mitochondria where the electron transport chain is located.

Lipid-soluble electron carrier

A molecule that can dissolve in the lipid bilayer and shuttle electrons between complexes.

Chemical energy

Energy stored in chemical bonds, released during chemical reactions.