Chapter 7 Microbial Metabolism

Metabolism

Refers to all chemical reactions and physical workings of a cell.

Anabolism

A building and bond-making process that synthesizes cell molecules and structures, forming larger macromolecules from smaller ones.

Catabolism

The process that breaks the bonds of larger molecules into smaller molecules and often releases energy.

Electron carriers

Molecules that shuttle electrons into a series of proteins, making energy usable for the cell.

Enzymes

Catalysts that increase the rate of chemical reactions; they do not become part of the products.

Substrates

Molecules acted upon by enzymes during a chemical reaction.

Cofactors

Non-protein components required by some enzymes to function, including organic molecules known as coenzymes and inorganic elements.

Lock and Key model

A model illustrating how an enzyme's active site is specific to only one substrate.

Glycolysis

The metabolic pathway that converts glucose into two molecules of pyruvic acid.

Krebs Cycle

A sequence of reactions that generates energy through the oxidation of Acetyl-CoA, producing CO2, NADH, FADH2, and ATP.

ATP (Adenosine Triphosphate)

The primary energy currency of the cell that stores and transfers energy needed for cellular functions.

Aerobic Respiration

A metabolic process that converts glucose to carbon dioxide and water, yielding a high amount of ATP with oxygen as the final electron acceptor.

Fermentation

An anaerobic process that partially oxidizes glucose to produce energy, typically yielding fewer ATP than aerobic respiration.

Redox Reactions

Chemical reactions involving the transfer of electrons, where one substance loses electrons (oxidation) and another gains electrons (reduction).

Amphibolism

The ability of a metabolic system to integrate both catabolic and anabolic pathways to improve cellular efficiency.

Essential Amino Acids

Amino acids that must be obtained from the diet because the body cannot synthesize them.

Conjugated Enzymes (Holoenzymes)

Enzymes composed of a protein portion (apoenzyme) and non-protein components (cofactors).

Competitive Inhibition

A process where a mimic molecule competes with the actual substrate for the active site of an enzyme, inhibiting its function.

Non-Competitive Inhibition

Occurs when a molecule binds to an allosteric site on the enzyme, altering the enzyme's shape and preventing substrate binding.

Active Site

The specific region of an enzyme where substrate molecules bind and undergo a chemical reaction.

Biochemical Pathway

A sequence of enzymatic reactions where a substrate is converted into a product, often forming linear or cyclical networks.

Feedback Inhibition

A regulatory mechanism whereby the end product of a metabolic pathway inhibits an earlier step in the pathway to prevent overproduction.

Denaturation

The process by which weak bonds maintaining the native shape of an enzyme are disrupted, leading to loss of function.

Oxidative Phosphorylation

The process in which ATP is synthesized using the energy from electron transport and the proton motive force.

Hydrogenation

The addition of hydrogen molecules to a compound during a redox reaction, primarily involved in energy transfer.