Microbiology Essentials and Bacterial Structure Flashcards

Vocabulary flashcards covering cellular classifications, microbial relationships, pathogen concepts, cell wall morphology, staining characteristics, transport mechanisms, and cellular structures based on lecture notes.

Prokaryotic cell

A cell characterized by having DNA that is not enclosed within a membrane-bound nucleus.

Bacteria and Archaea

The two domains that contain prokaryotic organisms.

Viruses

A group of acellular infectious agents rather than cellular organisms.

Eukaryotic cell

A cell type distinguished by containing a membrane-bound nucleus and membrane-bound organelles.

Archaea

A domain of generally unicellular, prokaryotic organisms that are distinct from bacteria at the molecular level.

Binomial nomenclature

The system of naming organisms where the scientific name consists of two parts: the genus and species.

Microbial strain

A genetically distinct variant within a microbial species.

Diplococci

A bacterial arrangement where spherical cells are attached to each other in pairs.

Streptobacilli

A bacterial arrangement consisting of rod-shaped cells linked in long chains.

Microbiome

The community of microorganisms inhabiting a particular environment.

Commensalism

A symbiotic interaction in which a microorganism benefits from living on a human host while the host is neither helped nor harmed.

Mutualism

A symbiotic relationship in which both the host and the microorganism benefit from the interaction.

Parasitism

A relationship where a microorganism benefits at the expense of harming its human host.

True pathogen

A pathogen that can cause disease in a healthy host.

Opportunistic pathogen

A pathogen that usually causes disease only when normal host defenses or conditions are disrupted.

Dysbiosis

A major disruption or imbalance of a normal microbial community, such as that caused by antibiotic treatment.

Biofilm

A microbial community attached to a surface and embedded in a self-produced extracellular matrix.

Human Microbiome Project

A research initiative with the major goal to characterize the microorganisms associated with the human body.

Bioremediation

A microbial application that utilizes microorganisms to help clean up environmental contaminants.

Germ theory

The core medical theory stating that specific microorganisms can cause infectious diseases.

Koch's postulates

A set of experimental criteria used to establish a causal relationship between a specific microorganism and a specific disease.

Coccus

A spherical bacterial cell shape.

Bacillus

A rod-shaped bacterial cell shape.

Vibrio

A comma-shaped curved bacterial cell morphology.

Spirillum

A bacterial morphology characterized by a long, rigid spiral form.

Spirochete

A bacterial morphology characterized by a flexible, tightly coiled spiral shape.

Pleomorphic

Describes a bacterial cell whose shape can vary under different environmental conditions.

Binary fission

An asexual form of reproduction without spores in which one prokaryotic cell divides into two genetically similar daughter cells.

Gram-positive bacteria

Bacteria that possess a thick peptidoglycan layer and teichoic acids, trapping the crystal violet-iodine complex during staining.

Gram-negative bacteria

Bacteria that possess a thin peptidoglycan layer, an outer membrane with lipopolysaccharide, and stain pink/red.

Outer membrane

A membrane unique to Gram-negative cell envelopes that contains lipopolysaccharides.

Lipid A

The lipid component of lipopolysaccharide responsible for its toxic/endotoxin activity during Gram-negative infections.

Acid-fast bacteria

Bacteria with a cell wall containing high concentrations of mycolic acids that resist decolorization during specialized staining.

Teichoic acids

Cell envelope components found in Gram-positive bacteria but absent in Gram-negative bacteria.

Mycoplasma

A genus of bacteria that naturally lack a cell wall and rely entirely on their plasma membrane for structural support.

L-form bacterium

A bacterial cell that has lost its cell wall.

Periplasmic space

The compartment located between the inner and outer membranes in Gram-negative bacteria.

Plasma membrane

A selective phospholipid barrier containing proteins that perform transport, sensing, and energy-generation functions.

Simple diffusion

The passive transport of small nonpolar molecules directly across the phospholipid bilayer from high to low concentration.

Facilitated diffusion

Passive transport mechanism utilizing membrane proteins to move substances down their concentration gradient without energy input.

Osmosis

The net movement of water across a selectively permeable membrane toward an area of higher solute concentration.

Primary active transport

A cell transport process that directly consumes cellular energy to move solutes against their concentration gradient.

Secondary active transport

A transport process driven by an established ion gradient generated by another energy-dependent mechanism.

Phosphotransferase system (PTS)

A group translocation transport system in bacteria that moves certain sugars into the cell while simultaneously phosphorylating them.

Flagellum

A specialized bacterial surface appendage primarily responsible for cellular motility.

Fimbriae

Short surface structures on bacteria commonly utilized for attachment to surfaces or host tissue.

Sex pilus

A specialized bacterial appendage that mediates the transfer of genetic material during bacterial conjugation.

Glycocalyx

An external layer of polysaccharides or proteins surrounding a bacterial cell that aids in protection and surface attachment.

Nucleoid

The non-membrane-bound nuclear region in a bacterial cell containing the main bacterial chromosome.

Bacterial ribosomes

Internal cellular structures responsible for protein synthesis.

Inclusion bodies

Intracellular storage structures in bacterial cells that hold reserve nutrients or metabolic products.

Endospore

A dormant, highly resistant structure formed by specific bacteria (such as Bacillus and Clostridium) to survive adverse environmental conditions.