Bacterial Cell Structure, Physiology, Metabolism, and Genetics

A set of 200 vocabulary flashcards covering bacterial structure, classification, metabolism, and genetics based on clinical microbiology lecture notes.

Pathogens

Bacteria that cause disease in humans.

MALDI-TOF MS

Matrix-assisted laser desorption/ionization-time-of-flight mass spectrophotometry.

Conventional identification time

Traditional method that typically takes $2-3$ days for results.

Molecular method result time

Advanced methods that can provide results in approximately $3$ hours.

Super bacteria

A term associated with the challenges presented by the indiscriminate use of antibiotics.

Anton Von Leeuwenhoek

A Dutch lens maker and biologist considered the Father of Protozoology and Bacteriology.

Wee beasties

The term Leeuwenhoek used to describe microbes found in a droplet of water.

Animalcules

Another name used by Leeuwenhoek for the microorganisms he discovered using his homemade microscope.

Prokaryote

Derived from the Greek meaning "before kernel," these cells lack a nuclear membrane and true nucleus.

Eukaryote

Derived from the Greek words "eu" (well/good) and "karyon" (kernel), these cells possess a true nucleus and membrane-bound organelles.

Typical prokaryotic diameter

$0.4-2\,\mu m$.

Typical prokaryotic length

$0.5-5\,\mu m$.

Nucleoid

The region in the prokaryotic cytosol where chromosomal DNA is located.

Mesosome

A sac-like structure in the cell membrane where chromosomal DNA is attached in prokaryotes.

Plasmids

Small circular molecules of DNA in the cytoplasm containing accessory information, commonly found in gram-negative bacteria.

Binary fission

The asexual reproduction method used by prokaryotes.

Prokaryotic ribosomes

$70S$ complex consisting of $50S$ and $30S$ subunits.

Eukaryotic ribosomes

$80S$ complex consisting of $60S$ and $40S$ subunits.

Svedberg (S) units

Sedimentation rates during high-speed centrifugation.

Acellular

Not composed of cells, a characteristic of viruses.

Mycoplasmataceae

The only prokaryotic family that possesses sterols in its cytoplasmic membrane.

Peptidoglycan

The primary component of most bacterial cell walls; also known as murein.

Glycocalyx

An organized capsule or unorganized slime layer present in many bacteria.

Flagellin

The polymer that composes simple prokaryotic flagella.

Cilia

Motility organelles present in eukaryotes but absent in prokaryotes.

Pili and fimbriae

Hairlike appendages present in prokaryotes but absent in eukaryotes.

Protozoa

Unicellular eukaryotic parasites, such as amoeba.

Metazoa

Multicellular parasites, such as tapeworms.

Pseudopodia

Locomotion organelles described as "false feet."

Hyphae

Filaments that interweave to form mats in fungi.

Mycelia

The mats formed by the interweaving of fungal hyphae.

Yeast

Unicellular fungi that reproduce asexually and lack hyphae or mycelia.

Mold

Multicellular fungi that reproduce both asexually and sexually.

Dimorphic fungi

Fungi that exist as yeast at human body temperature ($37\,^\circ C$) and filaments at room temperature ($22\,^\circ C$).

Heterotrophic

Organisms that obtain nutrients through absorption or ingestion rather than producing their own.

Bacteriophage

A virus that can infect and destroy bacterial cells; Greek for "to eat."

Cytopathic effect

Visible changes in host cells caused by viral infection.

Virion

A complete virus particle outside of a cell.

Taxonomy

The orderly grouping of organisms into taxa (categories) based on the Greek words for arrangement and law.

Nomenclature

The component of taxonomy providing naming assignments for each organism.

Genotype

The genetic makeup of an organism, including combinations of forms of genes.

Phenotype

The observable physical and functional features of an organism expressed by its genotype.

Taxa

The plural form of taxon, representing categories or subsets in taxonomy.

Domain

The broadest level of formal bacterial classification.

Bacterial Family suffix

Always capitalized and ends in "-aceae."

Genus

Equivalent to a human last name in the naming convention; capitalized and italicized.

Epithet

The proper word for a species name; written in lowercase and italics.

sp.

Abbreviation for species when singular.

spp.

Abbreviation for species when plural.

Strains

Variations of the same organism.

Biotype

Strains grouped by differences in biochemical or physiological properties.

Serotype

Strains distinguished by specific antigens detected using antibodies.

Serovar

A serologically defined variety or strain.

Numeric taxonomy

A system where phenotypic characteristics are assigned numbers to identify bacteria via a database.

Phage typing

Subdividing species based on susceptibility to specific bacterial phages.

Archaea

Extremophiles that are more closely related to eukaryotes and lack peptidoglycan in their cell walls.

Halophiles

Salt-loving cells that grow under extreme environmental conditions.

Thermophiles

Heat-loving cells that grow at high temperatures between $50\,^\circ C$ and $60\,^\circ C$.

Chromatin body

Another name for the diffuse nucleoid in bacteria.

Metachromatic granules

Storage deposits of polysaccharides or lipids visible when stained with methylene blue.

Endospores

Small, dormant, asexual spores developed inside a thick wall as a means of survival.

Germination

The process of an inactive endospore becoming one vegetative cell under the right conditions.

Bacillus and Clostridium

Two primary examples of endospore-producing bacterial genera.

Clostridium tetani spore shape

Terminally located, resembling a tennis racquet or lollipop.

Plasma membrane functions

Acts as an osmotic barrier and is the site of electron transport for energy in prokaryotes.

Gram-positive cell wall

Characterized by a very thick peptidoglycan (murein) layer and teichoic acids.

Gram-negative cell wall

Characterized by a thin inner peptidoglycan layer and an outer membrane.

NAG

$N$-acetyl-D-glucosamine, a component of the glycan chain.

NAM

$N$-acetyl-D-muramic acid, a component of the glycan chain.

Lipid A

The inner region of LPS, also known as endotoxin.

O-specific polysaccharide

The antigenic region of the lipopolysaccharide (LPS).

Outer membrane of Gram-negatives

Acts as a barrier to hydrophobic compounds and permits water-soluble molecules through porins.

Periplasmic space

The gel-like matrix located between the outer and inner membranes of Gram-negative bacteria.

Acid-fast cell wall

A waxy layer containing over $60\%$ lipid, primarily mycolic acid.

Mycolic acid

A strong hydrophobic molecule that makes cells resistant to acid-alcohol decolorization.

Pleomorphic

The ability to have various shapes due to the lack of a rigid cell wall, as seen in Mycoplasma.

L-forms

Bacteria that have lost their cell walls and grow in hyperosmotic solutions.

Capsule

A discrete, organized polysaccharide covering that acts as a virulence factor to evade phagocytosis.

Slime layers

Diffuse layers of polysaccharides that aid in adherence and biofilm formation.

Monotrichous

A single flagellum at one end of the cell.

Lophotrichous

Multiple flagella in tufts at one end of the cell.

Peritrichous

Flagella distributed all around the bacterial cell.

Amphitrichous

Flagella located on both ends of the cell.

Conjugation pili

Protein tubes that connect two bacterial cells to mediate DNA exchange.

Histones

Basic proteins found in the eukaryotic nucleus around which DNA is wound.

Nucleolus

The site of rRNA synthesis inside the eukaryotic nucleus.

Rough Endoplasmic Reticulum

Studded with ribosomes; the site of protein synthesis in eukaryotes.

Smooth Endoplasmic Reticulum

The site of phospholipid synthesis; lacks ribosomes.

Golgi apparatus

Modifies and packages proteins sent from the rough ER.

Mitochondria

The main site of energy production (ATP) in eukaryotes.

Lysosomes

Organelles containing hydrolytic enzymes for the degradation of macromolecules.

Peroxisomes

Contain enzymes that break down hydrogen peroxide ($H_2O_2$).

Cocci

Spherical-shaped bacteria.

Diplococci

Spherical bacteria appearing in pairs.

Streptococci

Spherical bacteria appearing in chains.

Staphylococci

Spherical bacteria appearing in clusters.

Spirochetes

Spiral-shaped bacteria.

V-I-A-S

Mnemonic for Gram stain steps: Crystal Violet, Iodine, Alcohol-Acetone, Safranin.

Gram's Iodine

The mordant used to fix the primary stain in the Gram stain procedure.

Alcohol-acetone

The decolorizer used in the Gram stain procedure, typically a $1:1$ ratio.