General Bacteriology, Virology, Parasitology, and Mycology Practice Flashcards

A comprehensive set of vocabulary flashcards covering the morphology, physiology, genetics, and classification of bacteria, viruses, parasites, and fungi, as well as principles of immunology and epidemiology.

Cocci

Oval or spherical bacterial cells that are often arranged in clusters, pairs, or chains.

Peptidoglycan

A mucopeptide (murein) chain composed of alternate units of N-acetyl muramic acid (NAM) and N-acetyl glucosamine (NAG) molecules that provides rigidity to the bacterial cell wall.

Lipopolysaccharide (LPS)

A layer unique to gram-negative bacteria consisting of Lipid A (endotoxin), core polysaccharide, and O side chain (somatic antigen).

Plasmid

Extrachromosomal double-stranded circular DNA molecules that exist in a free state in the cytoplasm and are capable of independent replication.

Generation time

The time required for a bacterium to give rise to two daughter cells under optimum conditions.

Lag phase

The period in the bacterial growth curve between inoculation and the beginning of multiplication where bacteria increase in size due to accumulation of enzymes and metabolites.

Log phase

The phase in the bacterial growth curve where bacteria divide exponentially, making them biochemically active and uniformly stained.

Obligate aerobes

Bacteria that can grow only in the presence of oxygen, such as Pseudomonas and Mycobacterium tuberculosis.

Selective media

Solid culture media containing inhibitory substances that allow the growth of pathogens while inhibiting the normal flora present in a specimen.

Minimum inhibitory concentration (MIC)

The lowest concentration of an antimicrobial agent that will inhibit the visible growth of a microorganism after overnight incubation.

Transformation

The process of random uptake of free or naked DNA fragments from the surrounding medium by a bacterial cell and its heritable incorporation into the chromosome.

Transduction

The transmission of a portion of DNA from one bacterium to another by a bacteriophage.

Conjugation

The transfer of genetic material from a donor bacterium to a recipient bacterium through mating or direct contact via a conjugation tube.

Transposons

Mobile genetic elements (jumping genes) capable of intracellular transfer between chromosomes and plasmids in a cut-and-paste manner.

Virulence

The relative degree of pathogenesis or tissue damage produced by a particular strain of an organism.

Exotoxins

Highly potent, heat-labile proteins secreted by bacteria that diffuse into the surrounding medium and have specific pharmacological actions on particular tissues.

Virion

The entire virus particle, consisting of a nucleic acid (DNA or RNA) core surrounded by a protein coat called a capsid.

Prions

Abnormal infectious protein molecules without nucleic acid that are highly resistant to physical/chemical agents and cause neurodegenerative brain conditions.

Eclipse phase

The interval between the penetration of a virus into a host cell and the appearance of the first infectious progeny particle.

Definitive host

An organism in which a parasite undergoes the sexual cycle of its development.

Autoinfection

A process where an intestinal parasite re-infects the same person via contaminated hands or reverse peristalsis.

Dimorphic fungi

Fungi that exist as molds (hyphal form) in the environment at $25^{\circ}\text{C}$ and as yeasts in human tissues at $37^{\circ}\text{C}$.

Resident flora

The life-long microbial community members associated with a particular body area that re-establish themselves if disturbed.

Probiotics

Live microorganisms which, when administered in adequate amounts, confer a health benefit to the host by restoring normal flora.

Endemic

A disease that occurs at a persistent, usually low level in a specific geographical area.

Pandemic

An infection that spreads rapidly across large areas of the world, often affecting multiple countries or continents.

Incidence rate

The number of new cases of a disease occurring in a defined population during a specified period of time.

Innate immunity

The inborn, non-specific resistance against infections that an individual possesses from birth, acting as the first line of host defense.

Acute phase reactant proteins (APRs)

Proteins synthesized by the liver whose levels increase or decrease exponentially during acute inflammatory conditions.

C-reactive protein (CRP)

An acute phase reactant that precipitates with the C-carbohydrate antigen of pneumococcus and serves as a non-specific marker of inflammation.