BSC002.23 Microbiology and Parasitology Lecture Notes

Flashcards covering the fundamentals of microbiology, bacterial morphology, growth requirements, sterilization methods, normal flora, and the immune response based on the BSC002.23 lecture transcript.

Microbiology

The study of organisms that are so small they cannot be seen with the naked eye; derived from "mikros" (small), "bios" (life), and "logia/logos" (study).

Bacteriology

The study of bacteria.

Virology

The study of viruses.

Mycology

The study of fungi.

Parasitology

The study of protozoa and parasitic worms.

Phycology

The study of algae.

Immunology

The study of the immune system and the immune response.

Saprophytes

Microorganisms that act as decomposers of waste products and dead organisms, essential in maintaining a balanced ecosystem.

Normal flora

Microorganisms that are everywhere (air, environment, and body), also referred to as indigenous flora.

Robert Hooke

Scientist who discovered the cell in the mid-1600s, leading to the Cell Theory.

Anton van Leeuwenhoek

Known as the "Father of Microbiology"; first to provide accurate descriptions of bacteria, protozoa, and fungi, which he termed "animalcules."

Louis Pasteur

Scientist who developed pasteurization and the Germ Theory of Disease; he also introduced the terms aerobes and anaerobes.

Edward Jenner

Scientist who discovered the smallpox vaccine.

Joseph Lister

Scientist who developed aseptic surgery in the late 1800s.

Robert Koch

Scientist who formulated Koch's postulates to prove that specific microorganisms cause certain diseases.

Salvarsan

Known as "the magic bullet" of chemotherapy, discovered by Paul Ehrlich for the treatment of syphilis.

Alexander Fleming

Scientist who discovered the antibiotic penicillin from the mold Penicillium notatum.

Prokaryotes

Organisms that do not possess a true nucleus or membrane-bound organelles (e.g., bacteria).

Eukaryotes

Organisms that possess a true nucleus and membrane-bound organelles; include plants, animals, fungi, parasites, and algae.

Viruses

Acellular organisms possessing only DNA or RNA; they are obligate intracellular parasites dependent on host cells for replication.

Nucleoid

The area in a prokaryotic cell containing genetic material, characterized by having no true nucleus or nuclear membrane.

Mesosome

A structure in prokaryotic cells that functions as mitochondria and the Golgi complex; also involved in cell division and secretion.

Capsid

The outer surface of a virus, composed of repeating sub-units called capsomeres.

Peptidoglycan

The principal component of the bacterial cell wall, also known as murein or mucopeptide.

Acid-fast bacteria

Bacteria with a lipid-rich cell wall composed of mycolic acids, making them hydrophobic (e.g., Mycobacterium tuberculosis).

Chitin

The main component of the outer surface (cell wall) of fungi.

Ergosterol

The primary substance that makes up the cell membrane of fungi.

Pellicle

The outer surface of protozoa.

Cyst

The infective stage of most protozoa.

Trophozoite

The pathologic or active stage of most protozoa.

Cellulose

The primary component of the outer surface of algae.

Cocci

Spherical or round-shaped bacteria.

Bacilli

Rod-shaped bacteria.

Vibrio

Comma-shaped curved bacteria (e.g., Vibrio cholerae).

Glycocalyx

A gelatinous outermost covering of some bacteria; called a capsule if strongly attached or a slime layer if loosely attached.

Teichoic acids

Surface antigens of gram-positive organisms that can elicit an antibody response and provide tensile strength to the cell wall.

Porins

Special protein channels in the outer membrane of gram-negative bacteria that allow the passage of low-molecular-weight hydrophilic substances.

Lipid A

A complex glycolipid in the outer leaflet of gram-negative bacteria responsible for endotoxin activity.

Periplasmic space

A fluid-filled space between the outer membrane and the inner plasma membrane in gram-negative bacteria containing enzymes.

Flagella

Thread-like structures made of flagellin protein that serve as organs for motility.

Monotrichous

Bacteria possessing a single polar flagellum.

Lophotrichous

Bacteria possessing a tuft of flagella at one end.

Amphitrichous

Bacteria possessing flagella at both ends.

Peritrichous

Bacteria possessing flagella all around the cell.

Pili

Also called fimbriae; rigid surface appendages that function for adherence (common pili) or gene exchange (sex pili).

Axial Filaments

Also called endoflagella, found in spirochetes; bundles of fibrils that rotate to propel the organism forward.

Endospores

Structures composed of dipicolinic acid and calcium ($calcium dipicolinate$) that confer resistance to heat, drying, and chemicals.

Thermophiles

Microbes that grow best at temperatures higher than $$40\,^\circ\text{C}$.

Mesophiles

Microbes that require an optimal temperature of $$20-40\,^\circ\text{C}$.

Psychrophiles

Microbes that require an optimum temperature of $$10-20\,^\circ\text{C}$.

Obligate aerobes

Organisms that strictly require oxygen for growth.

Obligate Anaerobes

Microbes that cannot survive in the presence of oxygen due to a lack of enzymes to break down free radicals.

Capnophiles

Organisms that may require the addition of carbon dioxide to enhance their growth.

Neutrophiles

Microorganisms that grow best in pH $6.5-7.5$; includes most medically important bacteria.

Lag Phase

The period of adjustment in the bacterial growth curve where metabolic activity increases but there is no appreciable increase in cell number.

Log Phase

Also called the exponential phase; characterized by rapid cell division and the determination of generation time.

Stationary Phase

A period of equilibrium where the number of living cells equals the number of dead cells as nutrients deplete.

Death Phase

Period of rapid cell death where the number of dead cells exceeds the number of living cells.

Resident Flora

Organisms of a fixed type regularly found in a given area of the body at a given age.

Transient Flora

Microorganisms that inhabit the skin and mucous membranes temporarily (hours to weeks) from the environment.

Medical Asepsis

Also called clean asepsis; refers to the reduction and prevention of spread of disease-causing microorganisms.

Surgical Asepsis

Also called sterile asepsis; the complete absence of all microorganisms.

Thermal death time

The minimum time required to kill a suspension of an organism at a predetermined temperature.

Tyndallization

Fractional or intermittent sterilization involving live steam at $100\,^\circ\text{C}$ for 30-90 minutes for 3 consecutive days.

Autoclave

Steam under pressure; considered the most efficient method of sterilization because it can destroy all microbial forms.

Bactericidal

Antimicrobial agents designed to kill the target bacteria.

Bacteriostatic

Antimicrobial agents designed to inhibit the growth of bacteria.

Incubation

The stage of infection from the entry of the microorganism into the body to the onset of signs and symptoms.

Prodromal

The stage of infection from the onset of non-specific symptoms to the appearance of specific symptoms.

Antigen

A substance recognized by the immune system that serves as the target of the immune response.

Epitope

The specific structure within an antigen that is recognized by B cells or T cells.

Hapten

A low molecular weight substance that only induces an immune response if bound to an immunogenic carrier.

Immunogen

Any substance capable of inducing an immune response, humoral or cell-mediated.

Innate Immunity

Natural, non-specific immunity present at birth, including physical barriers and second-line defenses like phagocytosis.

Adaptive Immunity

Specific, delayed immunity acquired after exposure to an antigen, characterized by immunological memory.

IgG

The most abundant immunoglobulin and the only one capable of crossing the placenta.

IgA

Secretory immunoglobulin found in colostrum, saliva, tears, and mucous membrane secretions.

IgM

The largest immunoglobulin (pentamer) and the first produced in the primary immune response.

IgE

Reaginic antibody mediating immediate hypersensitivity/allergy and providing defense against parasites.

IgD

A monomer on the surface of B cells that serves as a surface marker or antigen receptor.

Opsonization

The immune process of tagging foreign pathogens with opsonins (like antibodies) to enhance phagocytosis.

Passive immunization

The administration of purified antibodies (immune globulin) providing rapid but temporary protection.

Active immunization

The injection of vaccines to stimulate the body to produce its own specific antibodies for long-term protection.