Overview of Catabolism and Bioenergetics

These flashcards cover key vocabulary and concepts from the lecture on catabolism and bioenergetics.

Catabolism

The set of metabolic pathways that breaks down molecules into smaller units to release energy.

Bioenergetics

The study of the transformation of energy in living organisms.

Oxidation

A chemical process in which a substance loses electrons, often associated with the release of energy.

Glycolysis

The metabolic process that converts glucose into pyruvate, producing small amounts of energy (ATP) and NADH.

ATP (Adenosine Triphosphate)

The main energy carrier in cells, used to store and transfer energy.

Gibbs Free Energy (ΔG)

A thermodynamic quantity that measures the amount of energy in a system that can be used to perform work.

Exergonic Reaction

A reaction that releases energy, typically has a negative ΔG.

Endergonic Reaction

A reaction that absorbs energy, typically has a positive ΔG.

NADH (Nicotinamide Adenine Dinucleotide)

A coenzyme that acts as an electron carrier in oxidation-reduction reactions.

Citric Acid Cycle (Krebs Cycle)

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

Entropy (ΔS)

A measure of the disorder or randomness in a system; increases in entropy contribute to negative Gibbs free energy.

Chemical Equilibrium

The state in which the concentrations of reactants and products remain constant over time.

Enzyme

A protein catalyst that speeds up a chemical reaction without being consumed or altered in the process.

Activation Energy

The minimum energy that must be provided to compounds to result in a chemical reaction.

Thermodynamics

The branch of physical science that deals with the relations between heat and other forms of energy.

Phosphorylation

The addition of a phosphate group to a molecule, often used in the context of the synthesis of ATP.

Substrate-Level Phosphorylation

A form of ATP synthesis that occurs when a phosphate group is directly transferred to ADP from a phosphorylated intermediate.

Anaplerotic Reactions

Reactions that replenish depleted intermediates of metabolic pathways, such as the citric acid cycle.

Electron Transport Chain

A series of protein complexes and other molecules that transfer electrons through redox reactions to drive ATP synthesis.

Chemiosmosis

The movement of ions across a selectively permeable membrane, down their electrochemical gradient, which generates ATP.

Oxidative Phosphorylation

The process in which ATP is formed as electrons are transferred to oxygen via the electron transport chain.

Urea Cycle

The metabolic pathway through which excess nitrogen is excreted as urea.

Fermentation

A metabolic process that converts sugar to acids, gases, or alcohol in the absence of oxygen.

Photosynthesis

The process by which green plants and some other organisms use sunlight to synthesize foods with the help of chlorophyll.

Hydrolysis

A chemical process that splits a molecule by adding water.

Mitochondria

Organelles that are the powerhouse of the cell, generating ATP through respiration.

Redox Reactions

Reactions involving the transfer of electrons from one substance to another, involving oxidation and reduction.

Enzyme Regulation

The process of modulating enzyme activity, often through factors like allosteric sites, feedback inhibition, and covalent modification.