Bacterial Genetics and Virology Concepts

Vocabulary practice flashcards generated from lecture notes covering foundational concepts in bacterial genetics, microbiology, and virology.

Central Dogma

The core framework of molecular biology describing the flow of genetic information where DNA is replicated, transcribed into RNA, and translated into protein.

Gram Stain

A differential staining procedure developed by Hans Christian Gram that classifies bacteria as Gram-positive (purple) or Gram-negative (pink) based on cell envelope structure.

Bacteriophage structure

The physical organization of a bacterial virus, typically comprising a nucleic acid genome housed inside a head capsid, collar, tail, base plate, tail pins, and tail fibers.

lacZ

The bacterial gene symbol that specifically encodes the enzyme $\beta$-galactosidase.

Prototrophs

Bacteria that are capable of growing on minimal media without requiring additional organic growth factors beyond a basic carbon source.

Auxotrophs

Nutritional mutant bacteria that require organic substances, such as specific amino acids or vitamins, in addition to a carbon source for growth.

Nucleoid

The specific region within a prokaryotic cell where the supercoiled, circular double-stranded DNA chromosome is concentrated.

Gram-negative cell wall

A bacterial cell wall structure consisting of a thin peptidoglycan layer, a periplasmic space, and an outer membrane containing lipopolysaccharide (LPS).

Gram-positive cell wall

A bacterial cell wall structure characterized by a thick peptidoglycan layer containing embedded teichoic acid and lipoteichoic acid.

Streptomyces coelicolor

A multicellular bacterial species that forms hyphae and stalks of spores, and is known for producing antibiotics.

Escherichia coli

A single-celled, rod-shaped bacterium commonly utilized as a primary genetic model organism and pathogen.

Generation time

The time required for a microorganism to reach maturity and divide to produce offspring, which can be as fast as $20\,\text{minutes}$ in E. coli.

Clones

A population of cells derived from a single parent cell through asexual reproduction, rendering all progeny genetically identical.

Colony

A visible macroscopic cluster of bacterial growth on a solid agar medium originating from a single individual cell.

Extremophiles

Organisms, including many Archaea, that thrive in extreme environment conditions such as high-temperature sulfur springs or high-osmolarity waters.

Ribosomal RNAs (rRNAs)

Molecules whose sequence variations serve as the primary criterion for distinguishing the three main domains of life: Archaea, Bacteria, and Eucarya.

Phage display

A molecular method developed by George Smith in which a bacteriophage is engineered to display peptides or proteins on its capsule to evolve new proteins.

tracrRNA

A non-coding RNA molecule discovered by Emmanuelle Charpentier in Streptococcus pyogenes that complexes with CRISPR RNA and Cas9 to direct viral DNA cleavage.

Bacteriophage

An obligate bacterial parasite virus that infects bacterial cells, replicates inside them, and releases new viral particles upon cell lysis.

Virulent bacteriophage

A bacteriophage that exclusively undergoes lytic growth, resulting in host cell destruction and progeny release.

Prophage

The dormant state of a viral genome integrated into the host bacterial chromosome during the lysogenic cycle.

Lysogen

A bacterial strain harboring a silent prophage integrated within its genome.

Temperate bacteriophage

A virus capable of undergoing either lytic replication or integrating into the host bacterial chromosome via lysogeny.

Holin

A phage-encoded protein expressed during late lytic infection that functions by disrupting the host cytoplasmic membrane.

Lysozyme

An enzyme produced during late phage gene expression that degrades the peptidoglycan layer of the cell wall to induce cell lysis.

Lysate

The mixture of lysed bacterial cell debris and newly released infectious progeny bacteriophages.

Burst size

The total number of infectious bacteriophage progeny released from a single infected bacterium during lysis.

Induction

The event that triggers a prophage to excise from the bacterial chromosome and switch from the lysogenic cycle to the lytic cycle.

Plaque

A clear zone within a dense lawn of cultured bacteria caused by localized cycles of bacteriophage infection and cell lysis.

Multiplicity of Infection (MOI)

The quantitative ratio of adsorbed bacteriophage particles relative to the total number of host bacterial cells.