1-3 Microbiology Lecture Series Study Set

Comprehensive vocabulary flashcards covering microbial structures, pathogenicity, immunology, and control methods based on the lecture transcript.

Prokaryotic cells

Simple, usually unicellular organisms with no nucleus or membrane-bound organelles, containing $70S$ ribosomes and DNA in a nucleoid.

Eukaryotic cells

Complex cells that contain a nucleus and membrane-bound organelles such as the ER, Golgi, and mitochondria, with $80S$ ribosomes and a cytoskeleton.

Peptidoglycan

The cell-wall material in bacteria; it is thick in gram-positive bacteria and thin in gram-negative bacteria.

Endospore

An inactive, highly resistant, protective survival form of some bacteria.

Chemotaxis

The movement of a bacterium toward or away from chemicals.

Gram-negative

Bacteria characterized by a thin peptidoglycan layer, a periplasmic space, and an outer membrane containing LPS.

Lipopolysaccharide (LPS)

A component of the gram-negative outer membrane where lipid A acts as an endotoxin.

Dimorphic fungus

A type of fungus that can grow as either a yeast or a mold, such as Histoplasma capsulatum.

Dioecious

A condition in which male and female reproductive organs are found in separate organisms.

Bioremediation

The use of microorganisms to break down pollutants, sewage, oil, or toxic waste.

Virulence

The degree of harm or severity caused by a pathogen.

$$ID_{50}$$

The number of microbes required to infect $50\%$ of a test group.

$$LD_{50}$$

The number of microbes required to kill $50\%$ of a test group.

Antigenic drift

Small and gradual mutations occurring in viral antigens.

Antigenic shift

A major antigen change resulting from the reassortment of viral genomes, which can lead to pandemics.

Septicemia

A condition where bacteria are actively multiplying in the blood, leading to serious systemic illness.

Endotoxin

The heat-stable lipid A portion of LPS in gram-negative outer membranes, released during cell death or division.

Exotoxin

Powerful, usually heat-sensitive proteins secreted by living gram-positive or gram-negative bacteria.

Biofilm

A community of microbes attached to a surface and encased in a sticky protective matrix of extracellular polymeric substances (EPS).

Quorum sensing

Cell-to-cell communication among bacteria that is based on population size and signaling chemicals called autoinducers.

SEM (Scanning Electron Microscope)

A microscope that scans the surface of a specimen with electrons to produce detailed $3D$ surface images.

Differential stain

A staining procedure using multiple dyes to distinguish between different types of cells, such as the Gram Stain.

Zoonotic disease

An infectious disease that is spread from animals to humans.

Fomite

A nonliving object that can harbor and transmit microbes.

Adhesins

Attachment factors such as pili, fimbriae, capsules, and viral proteins that help pathogens attach to host cells.

Antimicrobial peptides

Chemical defenses that protect the host by damaging microbial membranes.

PAMPs

Common pathogen structures recognized by the innate immune system, such as peptidoglycan, LPS, flagellin, and viral RNA.

Morbidity

The state of being ill or the prevalence of disease within a population.

Sterilization

A process that destroys or removes all forms of microbial life, including highly resistant endospores.

D-value

The specific time required to kill $90\%$ of a microbial population under fixed conditions.

HTST (High-Temperature Short-Time)

A pasteurization method involving heating to $72^{\circ}C$ for $15$ seconds.

Selective toxicity

The quality of an antimicrobial drug that allows it to harm the target microbe more than the host.

MHC I

Molecules found on all nucleated cells that present antigens to cytotoxic $CD8$ T cells.

MHC II

Molecules found on APCs (dendritic cells, macrophages, and B cells) that present antigens to helper $CD4$ T cells.

Herd immunity

A phenomenon where a high percentage of immune individuals prevents a disease from spreading easily, protecting susceptible people.