Microbial Metabolism, Growth, Control, and Genetics Flashcards

A comprehensive set of vocabulary flashcards covering metabolic pathways, microbial growth requirements, control methods, antimicrobial pharmacology, and microbial genetics based on lecture and textbook content.

Metabolism

The sum of all chemical reactions within a living organism.

Catabolism

Chemical reactions that result in the breakdown of more complex organic molecules into simpler substances; these reactions usually release energy.

Anabolism

Chemical reactions in which simpler substances are combined to form more complex molecules; these reactions usually require energy.

Enzymes

Proteins produced by living cells that catalyze chemical reactions by lowering the activation energy.

Apoenzyme

The inactive protein portion of an enzyme.

Cofactor

The nonprotein portion of an enzyme which can be a metal ion such as iron, copper, magnesium, manganese, zinc, calcium, or cobalt.

Coenzyme

An organic molecule serving as a nonprotein portion of an enzyme, such as $NAD^+$, $NADP^+$, $FMN$, $FAD$, or coenzyme A.

Holoenzyme

The whole, active enzyme consisting of the apoenzyme plus a cofactor or coenzyme.

Oxidation

The removal of one or more electrons from a substrate, often accompanied by the removal of protons ($H^+$).

Reduction

The gain of one or more electrons by a substrate.

Glycolysis

The oxidation of glucose to pyruvic acid, which produces two $ATP$ and two $NADH$ molecules from one glucose molecule.

Respiration

An $ATP$-generating process in which molecules are oxidized and the final electron acceptor is an inorganic molecule.

Fermentation

A process that releases energy from sugars or other organic molecules by oxidation, does not require $O_2$, and produces only two $ATP$ molecules by substrate-level phosphorylation.

Psychrophiles

Microorganisms classified as "cold-loving" that have an optimum growth temperature of $10-15\,^{\circ}C$.

Mesophiles

Microorganisms classified as "moderate-temperature-loving" that include human pathogens with an optimum temperature of $35-37\,^{\circ}C$.

Thermophiles

Microorganisms classified as "heat-loving" that have an optimum growth temperature of $50-60\,^{\circ}C$.

Halophiles

Microbes that are salt-loving and can tolerate high salt concentrations or require high osmotic pressure.

Biofilms

Microbial communities that adhere to surfaces and form a gel-like slime layer; they are significantly more resistant to microbicides than free-swimming microbes.

Generation Time

The time required for a cell to divide or for a microbial population to double.

Lag Phase

The phase of microbial growth involving intense metabolic activity and preparation for population growth, but no increase in cell number.

Log Phase

The phase of exponential increase in population where bacteria are most susceptible to antimicrobial agents.

Stationary Phase

The period of equilibrium in a bacterial growth curve where microbial deaths balance the production of new cells.

Sterilization

The process of removing or destroying all microbial life on an object, including endospores.

Disinfection

The process of reducing or inhibiting microbial growth on nonliving surfaces.

Antisepsis

The process of reducing or inhibiting microorganisms on living tissue.

Bacteriostasis

A treatment that inhibits the growth and reproduction of microbes without killing them.

Autoclaving

A method of moist heat sterilization using steam under pressure at $121\,^{\circ}C$ and $15\,psi$ for $15\,minutes$.

Selective Toxicity

The property of an antimicrobial drug that allows it to destroy pathogens without causing excessive damage to the host.

Antibiotic

A substance naturally produced by a microbe that inhibits the growth of another microbe.

Broad-spectrum Antibiotics

Drugs that affect a wide range of bacteria, including both gram-positive and gram-negative species.

Synergism

An interaction where the effect of two drugs given together is greater than the sum of their individual effects.

Genetics

The study of what genes are, how they carry information, how information is expressed, and how they are replicated and transferred.

Genotype

The genetic composition of an organism, representing its entire complement of $DNA$.

Phenotype

The expression of genes resulting in the physical and functional traits of the organism.

Transcription

The process by which the enzyme $RNA$ polymerase synthesizes a strand of $RNA$ from a $DNA$ template.

Translation

The process in which the nucleotide base sequence of $mRNA$ is used to dictate the amino acid sequence of a protein.

Mutation

A permanent change in the nitrogenous base sequence of $DNA$.

Transformation

The process by which genes are transferred from one bacterium to another as "naked" $DNA$ in solution.

Conjugation

The transfer of genetic material between bacteria involving direct cell-to-cell contact through a sex pilus or mating bridge.

Transduction

A mechanism of horizontal gene transfer where $DNA$ is passed from one bacterium to another via a bacteriophage.