Cell as a Factory: Oxidative Phosphorylation and Metabolic Regulation

Flashcards covering key vocabulary from a lecture on cell metabolism, electron transport chain, and ATP synthesis.

Oxidative Phosphorylation

The metabolic pathway in which cells use enzymes to oxidize nutrients, thereby releasing energy which is used to reform ATP.

NADH

An electron carrier molecule; NAD+ is reduced to NADH, capturing electrons in the covalent bond, which can be released later.

Electron Transport Chain (Respiratory Chain)

A series of protein complexes located in the inner membrane of the mitochondria (or inner membrane of bacteria cells) through which electrons flow, enabling a bit of work to be done.

Ubiquinone (Q)

A small, mobile molecule (not a protein) within the electron transport chain that shuttles electrons between complexes.

Cytochrome C

A mobile protein within the electron transport chain that carries electrons between complexes.

Proton Gradient

The electrochemical gradient of protons across the inner mitochondrial membrane (or bacterial inner membrane), which stores potential energy.

Proton Motive Force

A description of the difference in the concentration of protons on one side of the membrane versus the other; acts like a force because gradients want to equilibrate.

ATP Synthase

A protein complex that acts like a molecular turbine, allowing protons to flow back into the mitochondrial matrix and coupling this movement to the generation of ATP.

Glycolysis

The process of splitting a glucose molecule into two pyruvate molecules, yielding a small amount of ATP and capturing electrons.

Citric Acid Cycle (Krebs Cycle)

A cycle that oxidizes acetyl CoA, producing electron carriers (NADH, FADH2) and releasing carbon dioxide.

Chemiosmotic Mechanism

The process by which the proton gradient is used to generate ATP via ATP synthase.

Brown Fat

A type of fat tissue containing a thermogenic channel protein in the inner mitochondrial membrane that uncouples ATP synthesis from electron transport, releasing energy as heat.

F0 and F1 Subunits of ATP Synthase

F0 is the membrane-bound portion of ATP synthase; F1 is the portion that projects into the mitochondrial matrix where ATP is generated.

Fermentation

An anaerobic process that regenerates NAD+ from NADH, allowing glycolysis to continue in the absence of oxygen.

Redox Balance

The maintenance of NAD+ levels in the cell, which is essential for glycolysis to continue.

Alcohol Dehydrogenase

The enzyme used by the yeast cell to produce ethanol.

Gluconeogenesis

The creation of glucose from other stuff, creating glucose from intermediates that come from other glycolysis or the citric acid cycle.

Allosteric Regulation

Regulation of an enzyme by binding of a molecule to a site other than the active site, changing the enzyme's shape and activity.

Catabolic Reactions

The reversible reactions to build up again from simpler precursors.

Oxidative Phosphorylation

The metabolic pathway in which cells use enzymes to oxidize nutrients, thereby releasing energy which is used to reform ATP.

NADH

An electron carrier molecule; NAD+ is reduced to NADH, capturing electrons in the covalent bond, which can be released later.

Electron Transport Chain (Respiratory Chain)

A series of protein complexes located in the inner membrane of the mitochondria (or inner membrane of bacteria cells) through which electrons flow, enabling a bit of work to be done.

Ubiquinone (Q)

A small, mobile molecule (not a protein) within the electron transport chain that shuttles electrons between complexes.

Cytochrome C

A mobile protein within the electron transport chain that carries electrons between complexes.

Proton Gradient

The electrochemical gradient of protons across the inner mitochondrial membrane (or bacterial inner membrane), which stores potential energy.

Proton Motive Force

A description of the difference in the concentration of protons on one side of the membrane versus the other; acts like a force because gradients want to equilibrate.

ATP Synthase

A protein complex that acts like a molecular turbine, allowing protons to flow back into the mitochondrial matrix and coupling this movement to the generation of ATP.

Glycolysis

The process of splitting a glucose molecule into two pyruvate molecules, yielding a small amount of ATP and capturing electrons.

Citric Acid Cycle (Krebs Cycle)

A cycle that oxidizes acetyl CoA, producing electron carriers (NADH, FADH2) and releasing carbon dioxide.

Chemiosmotic Mechanism

The process by which the proton gradient is used to generate ATP via ATP synthase.

Brown Fat

A type of fat tissue containing a thermogenic channel protein in the inner mitochondrial membrane that uncouples ATP synthesis from electron transport, releasing energy as heat.

F0 and F1 Subunits of ATP Synthase

F0 is the membrane-bound portion of ATP synthase; F1 is the portion that projects into the mitochondrial matrix where ATP is generated.

Fermentation

An anaerobic process that regenerates NAD+ from NADH, allowing glycolysis to continue in the absence of oxygen.

Redox Balance

The maintenance of NAD+ levels in the cell, which is essential for glycolysis to continue.

Alcohol Dehydrogenase

The enzyme used by the yeast cell to produce ethanol.

Gluconeogenesis

The creation of glucose from other stuff, creating glucose from intermediates that come from other glycolysis or the citric acid cycle.

Allosteric Regulation

Regulation of an enzyme by binding of a molecule to a site other than the active site, changing the enzyme's shape and activity.

Catabolic Reactions

The reversible reactions to build up again from simpler precursors.

Metabolic Pathway

A series of enzyme-catalyzed reactions in which a molecule is transformed step by step to yield a specific product

ATP (Adenosine Triphosphate)

ATP is a nucleotide that serves as the major energy currency of the cell.

NAD+

A molecule that functions as a reducing agent in many metabolic pathways.

Catabolism

The breakdown of larger molecules into smaller ones, often releasing energy.

Anabolism

The synthesis of complex molecules from simpler ones, which requires energy.