The Electron-Transport Chain and Oxidative Phosphorylation

These flashcards cover key vocabulary terms and concepts related to the electron-transport chain and oxidative phosphorylation.

Electron-Transport Chain

A series of protein complexes in the inner mitochondrial membrane that transfer electrons from NADH to oxygen while pumping protons.

Oxidative Phosphorylation

The process in which ATP is synthesized from ADP and inorganic phosphate, coupled to the electron transport chain.

Proton Gradient

A difference in proton concentration across a membrane, created by proton pumps during electron transport.

NADH-Q Oxidoreductase

The first complex in the electron transport chain (Complex I) that accepts electrons from NADH.

Succinate-Q Reductase

The second complex in the electron transport chain (Complex II) that transfers electrons from succinate to coenzyme Q.

Q-Cytochrome c Oxidoreductase

The third protein complex (Complex III) in the electron-transport chain that transfers electrons from reduced ubiquinone to cytochrome c.

Cytochrome c Oxidase

The final protein complex (Complex IV) that catalyzes the reduction of oxygen to water.

Coenzyme Q (Ubiquinone)

A lipid-soluble electron carrier that shuttles electrons between complexes in the electron-transport chain.

Cristae

The folds of the inner mitochondrial membrane that increase surface area for oxidative phosphorylation.

Proton-motive Force

The energy stored in a proton gradient that drives ATP synthesis.

Oxidation-Reduction Reaction

A chemical reaction involving the transfer of electrons, resulting in a change in oxidation states for the involved compounds.

Redox Potential

The tendency of a chemical species to acquire electrons and thereby be reduced, measured in volts.

Endosymbiotic Theory

The hypothesis that mitochondria originated from free-living bacteria that were engulfed by ancestral cells.

Flavin Mononucleotide (FMN)

A cofactor that serves as an electron carrier in Complex I of the electron transport chain.

Iron-Sulfur Proteins

Proteins that contain iron–sulfur clusters and play a role in electron transport as carriers in the chain.

Cyt c

Cytochrome c, a small heme protein that transports electrons from Complex III to Complex IV.

Respirasome

A supercomplex of mitochondrial electron transport chain components that enhances the efficiency of electron transfer.

Reactive Oxygen Species (ROS)

Highly reactive molecules derived from oxygen that can cause cellular damage, generated during electron transport.

Superoxide Dismutase

An enzyme that catalyzes the conversion of superoxide radicals to hydrogen peroxide and oxygen.

Catalase

An enzyme that breaks down hydrogen peroxide into water and oxygen.

ATP Synthase

An enzyme that synthesizes ATP using the energy from protons flowing back into the mitochondrial matrix.

Hydrophobic Tail

The long isoprenoid tail of coenzyme Q that allows it to be lipid-soluble and diffuse within the inner mitochondrial membrane.

Ferredoxin

An iron-sulfur protein involved in electron transport and redox reactions in photosynthesis and respiration.

Lipoate

A cofactor that can participate in redox reactions and is involved in the citric acid cycle.

Peroxisome

An organelle that contains enzymes for breaking down fatty acids and detoxifying harmful peroxides.

Eukaryotic Cells

Cells that contain membrane-bound organelles, including mitochondria, necessary for oxidative phosphorylation.

Citric Acid Cycle

A series of chemical reactions used by all aerobic organisms to release stored energy through the oxidation of acetyl-CoA.

FAD (Flavin Adenine Dinucleotide)

An electron carrier in various metabolic reactions, particularly in the citric acid cycle and fatty acid oxidation.

Electromotive Force

The potential difference that drives electrons through the components of the electron transport chain.

Mitochondrial Matrix

The space within the inner mitochondrial membrane where the citric acid cycle occurs.

Hypoxic Zone

An area with low oxygen levels, often resulting from excessive respiration by marine organisms.

Barbiturates

Sedative drugs that can inhibit mitochondrial respiration by affecting electron transport.

Endosymbiotic Event

The historical occurrence where one organism was engulfed by another, leading to the formation of organelles like mitochondria.