Microbial Metabolism and Energy Pathways

These flashcards cover key vocabulary terms and definitions related to the metabolism of microbes, enzyme activity, energy pathways, and fermentation processes.

Metabolism

All chemical and physical workings of a cell.

Catabolism

Degradative reactions that break down larger molecules into smaller ones, releasing energy.

Anabolism

Biosynthetic reactions that form larger macromolecules from smaller molecules, requiring energy input.

Enzyme

Biological catalysts that increase the rate of a chemical reaction by lowering the energy of activation.

Activation Energy

The energy required to initiate a chemical reaction.

Apoenzyme

The protein portion of a conjugated enzyme.

Cofactor

The nonprotein portion of a conjugated enzyme; can be a metal ion or an organic molecule.

Endoenzymes

Enzymes retained intracellularly, functioning within the cell.

Exoenzymes

Enzymes transported extracellularly to break down larger food molecules or harmful chemicals.

Denaturation

The process where enzymes become unstable due to environmental changes, losing their functional shape.

Competitive Inhibition

Inhibition in which a substance competes with the normal substrate for the active site of an enzyme.

Noncompetitive Inhibition

Inhibition in which a regulatory molecule binds to an enzyme at a site other than the active site, altering its function.

Endergonic Reaction

A reaction that consumes energy, characteristic of anabolic processes.

Exergonic Reaction

A reaction that releases energy, characteristic of catabolic processes.

Oxidation

The removal of electrons from a molecule.

Reduction

The addition of electrons to a molecule.

Redox Reaction

A chemical reaction involving the transfer of electrons, where oxidation and reduction occur simultaneously.

ATP (adenosine triphosphate)

The energy currency of the cell, a molecule consisting of adenine, ribose, and three phosphate groups.

Substrate-level phosphorylation

The direct transfer of a phosphate group from a phosphorylated compound to ADP to form ATP.

Oxidative phosphorylation

The generation of ATP through the electron transport chain and chemiosmosis.

Photophosphorylation

The formation of ATP using the energy of light.

Anaerobic respiration

Respiration that utilizes electron acceptors other than oxygen, such as nitrate or sulfite.

Fermentation

A metabolic process that produces energy from the oxidation of organic molecules without requiring oxygen and does not use the Krebs cycle or electron transport chain.

Lactic Acid Fermentation

A type of fermentation that converts glucose to lactic acid, occurring in some bacteria and muscle cells.

Alcohol Fermentation

A type of fermentation that converts glucose to ethanol and carbon dioxide.

Chemiosmosis

The process by which ATP is produced using the energy of a hydrogen ion gradient across a membrane.