Biology: Antibiotic Resistance and Evolution

Vocabulary flashcards covering Module 7 lecture material on antibiotic modes of action, bacterial resistance evolution, population genetics, and evolutionary mechanisms.

Antibiotics

Any substance that inhibits the growth and reproduction of bacteria, or outright kills them, typically by targeting a cellular structure found in bacteria but not in animal cells.

Binary Fission

The form of asexual reproduction by which prokaryotes (bacteria) duplicate their single chromosome and divide into two cells, enabling populations to double every $4$ to $20\text{ minutes}$.

Tetracycline

An antibiotic that interferes with bacterial ribosomes, the cellular structures responsible for protein synthesis.

Penicillin

An antibiotic discovered from Penicillium mold that prevents bacterial survival by disrupting the proper formation of peptidoglycan cell walls.

Ciprofloxacin

An antibiotic that kills bacteria by disrupting an essential enzyme involved in organizing bacterial DNA within chromosomes.

Sulfa Drugs

A class of synthetic antimicrobial agents that inhibit bacterial growth by blocking a cytoplasmic enzyme needed to synthesize the nutrient folate.

Alexander Fleming

The Scottish physician and microbiologist who accidentally discovered the antibacterial properties of Penicillium mold against Staphylococcus aureus in 1928.

Zone of Inhibited Growth

The clear circular area surrounding an antibiotic disc on an agar culture plate where bacterial growth is completely prevented, showing bacterial susceptibility.

MRSA

Methicillin-resistant Staphylococcus aureus; a pathogenic bacterium that evolved resistance to penicillin and methicillin.

VRSA

Vancomycin-resistant Staphylococcus aureus; strains of Staphylococcus aureus first observed in the 1980s that developed resistance to the last-resort antibiotic vancomycin.

MDROs

Multidrug-resistant organisms (often referred to as 'superbugs'); microbial pathogens resistant to multiple clinical classes of antimicrobial treatments.

Population

All the individuals of the same species residing within a specific geographic area at the same time.

Evolution

A measurable change in the frequency of heritable traits within a biological population across successive generations.

Mutation

A random alteration in the nucleotide sequence of an organism's DNA, serving as the ultimate source of new genetic traits.

Natural Selection

A primary mechanism of evolution where organisms with favorable heritable traits survive and reproduce at higher rates than organisms lacking those traits under specific environmental pressures.

Selective Pressure

An external biotic or abiotic environmental force—such as predator preferences, resource scarcity, or antibiotic exposure—that determines which phenotypic traits confer a reproductive or survival advantage.

Scientific Theory

A comprehensive explanation of an aspect of the natural world supported by a vast body of empirical evidence and repeated experimental substantiation.

Artificial Selection

The selective breeding of organisms by humans over successive generations to encourage the propagation of specific desired phenotypic traits, such as crops derived from wild mustard.

Sexual Selection

A mode of natural selection where individuals with specific heritable traits are more successful than others at securing mates and achieving reproductive success.

Genetic Drift

An evolutionary mechanism causing stochastic, non-adaptive fluctuations in allele and trait frequencies across generations due purely to chance events.

Bottleneck Effect

A form of genetic drift resulting from a dramatic, rapid reduction in population size caused by environmental catastrophes or hunting, drastically curtailing overall genetic diversity.

Gene Flow

The movement and exchange of genetic alleles between distinct populations due to individual migration or gamete transfer, such as windblown pollen.

Antibiotic Stewardship

A coordinated program of practices designed to slow the emergence and spread of resistant pathogens by curbing unnecessary prescriptions, ensuring complete therapeutic courses, and reducing agricultural misuse.