Microbiology Ch.8- Metabolism: Catabolic and Anabolic Reactions

Metabolism

Sum of chemical reactions in an organism.

Catabolism

Breakdown of molecules for energy and building blocks.

Anabolism

Building large molecules using energy and building blocks.

Metabolic Pathway

Sequence of enzymatically catalyzed reactions in cells.

Enzymes

Proteins or RNA that catalyze biological reactions.

Induced Fit

Enzymes change shape upon substrate interaction.

Substrate

Molecule that binds and is modified by an enzyme.

Collision Theory

Reactions occur when molecules collide effectively.

Activation Energy

Energy needed to disrupt electronic configurations.

Reaction Rate

Frequency of effective collisions leading to reactions.

Holoenzymes

Complete enzymes made of apoenzyme and cofactor.

Apoenzyme

Protein portion of a holoenzyme.

Cofactor

Non-protein portion of an enzyme, often a metal.

Coenzyme

Organic cofactor, usually derived from vitamins.

Important Coenzymes

Examples include NAD+, FAD, and Coenzyme A.

Oxidoreductase

Enzymes that catalyze oxidation-reduction reactions.

Ligase

Enzymes that join molecules using ATP.

Labile Enzyme

Sensitive to environmental changes.

Stabile Enzyme

Not sensitive to environmental changes.

Enzyme Activity

Influenced by temperature, pH, and substrate concentration.

Competitive Inhibitor

Competes with substrate for active site binding.

Noncompetitive Inhibitor

Binds to allosteric site, altering substrate binding.

Feedback Inhibition

End product inhibits first enzyme in pathway.

Metabolic Pathways

Series of enzyme-catalyzed chemical reactions.

Enzyme Regulation

Control of enzyme expression and activity.

Constitutively Expressed Proteins

Proteins always synthesized and available.

Regulated Proteins

Proteins expressed based on environmental conditions.

Enzyme Repression

Stopping gene expression for an enzyme.

Enzyme Induction

Activating gene expression for an enzyme.

Competitive Inhibitors

Bind to enzyme's active site, blocking substrate.

Non-Competitive Inhibitors

Bind elsewhere on enzyme, altering activity.

Ribozymes

RNA molecules that catalyze biochemical reactions.

Oxidation

Removal of electrons from a molecule.

Reduction

Gain of electrons by a molecule.

Redox Reaction

Coupled oxidation and reduction reactions.

Biological Oxidations

Often involve dehydrogenation processes.

ATP Generation

Produced by phosphorylating ADP.

Substrate-Level Phosphorylation

Direct transfer of phosphate to ADP.

Oxidative Phosphorylation

Electron transfer generates H+ gradient for ATP.

Chemiosmosis

Utilization of H+ gradient to produce ATP.

Glycolysis

Initial glucose breakdown producing ATP and NADH.

Glucose Phosphorylation

Glucose converted to glucose 6-phosphate during transport.

Krebs Cycle

Oxidation of acetyl-CoA producing NADH and FADH2.

Electron Transport Chain

Series of carriers transferring electrons for ATP.

Heat Loss in Energy Transfer

Inefficient energy transfer results in heat loss.

Concentration Gradient

Difference in concentration across a membrane.

Periplasmic Space

Space between plasma membrane and cell wall.

Final Electron Acceptor

Molecule that accepts electrons in ETC.

Electron Transport Chain (ETC)

Series of proteins transferring electrons to generate ATP.

Traffic Jam in ETC

Blockage caused by absence of electron acceptor.

Oxidative Phosphorylation

ATP production using electron transport and chemiosmosis.

Proton Motive Force

Energy from H+ moving down concentration gradient.

ATP Synthase

Enzyme that synthesizes ATP using H+ gradient.

Aerobic Respiration

Respiration using oxygen as final electron acceptor.

Anaerobic Respiration

Respiration without oxygen as final electron acceptor.

Fermentation

Energy release without oxygen, using organic molecules.

Alcohol Fermentation

Conversion of pyruvate to ethanol and CO2.

Lactic Acid Fermentation

Conversion of pyruvate to lactic acid.

Homolactic Fermentation

Produces only lactic acid from pyruvate.

Heterolactic Fermentation

Produces lactic acid and other compounds.

Protein Catabolism

Breakdown of proteins into amino acids.

Proteases

Enzymes that hydrolyze peptide bonds.

Deamination

Removal of amino group from amino acids.

Phenol Red

pH indicator that turns yellow in acidic conditions.

Substrate Level Phosphorylation

Direct ATP production from a metabolic pathway.

NADH Recycling

Conversion of NADH back to NAD+ during fermentation.

Krebs Cycle

Series of reactions generating energy through oxidation.

Biochemical Tests

Tests identifying bacteria based on enzyme presence.