Bacteriology and Microbiology Video Notes - Vocabulary Flashcards

Vocabulary flashcards covering core concepts in microbiology and bacteriology from the notes.

Microbiology

Study of microorganisms too small to be seen with the naked eye; algae and fungi are exceptions.

Culture (isolating and growing microbes)

Techniques for isolating, culturing, and studying microorganisms in agar plates (colonies) or broth.

Recombinant DNA (rDNA)

Biotechnological methods that insert DNA into organisms to produce useful products (e.g., insulin).

Bacteriology

The branch of microbiology that studies bacteria.

Normal microbiota

Microorganisms that normally reside in and on the human body, often providing benefits such as vitamin production.

Escherichia coli (E. coli) as a symbiont

Commensal gut bacterium that can protect by producing vitamin K and killing pathogens; can cause UTIs if misplaced.

Taxonomy

Biological classification, including classification, nomenclature, and identification.

Phylogeny

Comparative analysis of organisms based on evolutionary relationships.

Bacteria

unicellular prokaryotes with a peptidoglycan cell wall.

Peptidoglycan cell wall

Rigid polymer providing structure; thick in Gram-positive bacteria and thin in Gram-negative bacteria.

Gram-positive bacteria

Bacteria with a thick peptidoglycan layer that retain the crystal violet stain (purple).

Gram-negative bacteria

Bacteria with a thin peptidoglycan layer and an outer membrane; stain pink after washing of the counterstain.

Archaea

Domain of life lacking peptidoglycan; distinctive membrane lipids; often extremophiles.

No peptidoglycan (in archaeal cell walls)

Archaeal cell walls lack peptidoglycan and use different structural polymers.

16S rRNA gene sequence

Conserved gene used for bacterial/archaeal phylogeny and identification.

Archaea membrane lipids (ether linkages)

Ether-linked lipids in archaeal membranes, contributing to stability in extreme environments.

Crenarchaeota

Archaea typically thermophilic or hyperthermophilic, inhabiting extreme environments.

Euryarchaeota

A major archaeal group including methanogens, halophiles, and some extremophiles.

Methanogens

Archaea that produce methane in anaerobic environments.

Halophiles

Archaea adapted to high-salt environments.

Thermoacidophiles

Archaea thriving in hot, acidic conditions.

Eukaryotes: Protista

Unicellular eukaryotic organisms; included in early eukaryotic classification.

Viruses

Obligate intracellular parasites that require host cells to replicate; not classified in a kingdom.

Virus host range and receptors

Range defined by virus ability to attach to host cell receptors; determines which cells/plants/animals can be infected.

Viral genomes (dsDNA, ssDNA, dsRNA, ssRNA)

Variants of viral genetic material; genomes can be double- or single-stranded and linear or circular.

Prophage

Bacteriophage genome integrated into a bacterial chromosome during lysogeny.

Plasmid

Extra-chromosomal DNA that can carry genes and alter bacterial phenotype.

Transformation

Uptake of naked DNA from the environment by bacteria.

Transduction

DNA transfer between bacteria mediated by bacteriophages.

Conjugation

DNA transfer between bacteria through direct contact via pili.

Core genome

Genes present in all strains of a species.

Pan genome

Core genome plus accessory/mobile genes that aren’t in every strain.

Polyphasic taxonomy

Classification using a mix of phenotypic and genotypic data to reduce contradictions.

Ribosomal DNA (rDNA) data

Phylogenetic data derived from ribosomal RNA sequences (e.g., 16S) used for taxonomy.

Cell membrane (plasma membrane)

Phospholipid bilayer that acts as a selective barrier and site of energy processes; gatekeeper for diffusion.

Phospholipid bilayer

Two-layer arrangement of phospholipids forming the cell membrane; hydrophobic interior with hydrophilic surfaces.

Cell wall (bacterial)

Rigid layer outside the membrane made of peptidoglycan; confers shape and protection.

LPS (lipopolysaccharide)

Endotoxin-like component of the outer membrane in Gram-negative bacteria; acts as a barrier.

Lipid-teichoic acids (LTA)

Teichoic acids anchored in the cytoplasmic membrane of Gram-positive bacteria.

Motility structures: Flagella

Long, whip-like appendages enabling bacterial movement; composed of flagellin; ~20 nm in diameter.

Flagellar arrangements

Different patterns: atrichous (no flagella), monotrichous (one), amphitrichous (one at each end), lophotrichous (tufts), peritrichous (all over).

Chemotaxis

Movement toward or away from chemical stimuli, involving running and tumbling.

Gliding motility

Surface movement without flagella, often via secreted mechanisms.

Twitching motility

Surface movement using Type IV pili to pull the cell along.

Swarming motility

Rapid, coordinated surface movement forming multicellular colonies.

Fimbriae and pili

Hair-like structures; fimbriae for attachment; pili (including conjugation pili) for DNA transfer.

Type IV pili

Pili involved in attachment, motility, and DNA uptake; important for invasion and horizontal gene transfer.

Biofilms

Sessile microbial communities attached to surfaces, embedded in a self-produced EPS matrix.

EPS (extracellular polymeric substances)

Matrix of polysaccharides, proteins, lipids, and nucleic acids that holds biofilm together.

Biofilm life cycle

Attachment (reversible then irreversible), maturation, and dispersal.)

DLVO theory

Colloidal theory describing reversible adhesion via van der Waals and electrostatic forces; explains initial attachment dynamics.

Irreversible adhesion

Firm attachment mediated by polymer bridging and specific receptors; not explained by DLVO.

Polymer bridging

Interaction where polymers connect surfaces and cells to enable irreversible adhesion.

Exopolymers

Polymers secreted by microbes (e.g., exopolysaccharides, fibrillar proteins) that form the EPS matrix.

Lipoteichoic acids (LTA)

Teichoic acids associated with Gram-positive membranes, contributing to adhesion and cell wall function.

Lipopolysaccharides (LPS)

Molecule in Gram-negative outer membrane; contributes to barrier function and immune interactions.

A-layer and S-layer

Crystalline surface layers found on some bacteria, providing protection and structural support.