Exam 1 Flashcards
What is symbiosis?
Neutral, antagoistis or synergistic relationship between 2 dissimular organisms (symbiotes/symbionts) living in close association with each other.
What is Mutualism?
Mutually beneficial relationship between two species.
What is commensalism?
Relationship between 2 species where one benefits and the other is not affected.
What is parasitism?
Relationship between 2 species where one benefits (parasite) from the other (host); usually detrimites the host but not always
Where is the highest amount of resident microbes?
The large intestine.
What/where is the resident flora of the skin?
Where=the epidermis
What=mostly staphylococcus
What/where is the resident flora of the oral cavity?
Where=cheeks, gum, teeth
What=streptococcus species
What/where is the resident flora of the stomach and intestine?
- gastric Helicobacter pylori
- L. intestine mostly anaerobic microbes
- microbes like E. coli and Lactobacillus
What is the resident flora of the upper respiratory tract?
- streptococcus and staphylococcus
- lower respiratory tract should be sterile
Whats is the resident flora of the genital tract?
- vaginal flora is influenced by hormones
- change in flora after puberty
- Lactobacillus
What is the resident flora of the urethra?
Many opportunitic microbes
What are the 4 roles of normal flora?
- Common source of infection
- Immune stimulation
- Keep out invadors
- Nutrition and metabolism
What are the 4 factors controlling the growth of microorganisms?
- Nutrient availability
- Environment
- Competition
- Host immune system
What is a fastidious organism?
An organism that has complex nutritional or cultural requirments, making isolation and culture more difficult.
What parameters are involved in the environment?
- Water activity (osmotic pressure)
- Oxygen requirements
- pH of the environment
- temperature
How is an infectious agent accquired?
- Enters the host
- Colonization
- Invasion
- Multiplication
What are some entries/exits?
- Ingestion
- Inhalation
- direct penetration
What does colonization mean?
Successful occupation of a new habitat by a species not normal found in that niche.
What does adherence mean?
Close association of bacterial cells and host cells generally characterized by receptors on target sites.
What is adhesin?
Structure or macromolecule located on the surface of a cell that facilitates adherence of a cell to a surface or to another cell.
What does invasion mean?
Entry and spread throughout cells and/or tissues of the host. (specific recognition of receptor sites on target cells enhances pathogenic advantage)
What are invasins (invasive factors)?
Structures or macromoles that facilitate invasion by a pathogenic microoganism.
What does multiplication mean?
The ability of a microorganism to reproduce during an infection; influenced by underlying disease, immunologic status, antibiotic treatment, nutrient availability
What is a vector?
A carrier; the animal that transfers an ifectious agent from one host to another, usually an arthropod.
What is a carrier?
A symptomless individual who is a host to a pathogenic microoganism with the potential to pass the pathogen to others.
What is a nosocomial infection?
An infection acquired in a hospital setting that was not present in the host prior to admission (generally occuring within 72 hrs).
What is pathogenicity?
Quality of producing disease or ability to produce pathologic changes or disease.
What is virulence?
Measure of pathogenicity; measurement of degree of disease-producing ability of a microorganism as indicated by severity of disease produced.
What does dosage mean?
Number of pathogenic organisms entering a host.
What is a true pathogen?
Any miccroorganism capable of cause a disease (infectious agent).
What is an opportunistic pathogen?
A usually harmless organism that becomes pathogenic under favorable conditions causing an opportunistic infection.
What does infection mean?
Colonization and/or invasion and multiplication of pathogenic microoganisms in a host with or without manifestation of disease.
What does disease mean?
Abnormal condition of bofy function(s) or structure that is considered harmful to the affected individual (host).
What does contagious mean?
Capable of being transmitted from one host to another.
What is an infectious dose?
Number of pathogenic organisms required to cause disease in a given host.
What does epidemic mean?
Disease occuring suddenly in numbers clearly in access of normal expectancy.
What does endemic mean?
A disease present or usually prevalent in a population or geographical area at all times.
What does pademic mean?
A widespread epidemic distributed or occuring widely throughout a region, country, contient, or globally.
What are Koch’s 4 postulates?
- pathogen must be present in all cases of disease
- pathogen can be isolated from the diseased host and grown in pure culture
- pathogen from pure culture must cause same disease when inoculated into a susceptible animal
- pathogen must be reisolated from new host and shown to be same as the originally inoculated
What is absent in bacteria that is present in fungi?
- Nuclear membrane
- mitochondria
- ER
- sterols in cytoplasmic membrane
- chitin, glucans, and mannans from cell wall
What does a sex pilus do?
mediates DNA transfer during conjugation
What does common pili or fimbriae do?
attachment to surface; protection against phagotrophic engilfment
What do capsules do?
- attachment to surfaces
- protection against phagotrophic engulfment
- reserve of nutrients or protection against dessication
What is the purpose of the cell wall?
Prevents osmotic lysis, confers rigidity and shape on cells.
What is the purpose of the plasma membrane?
- Permeable barrier
- transport of solutes
- energy generation
- location of many enzyme systems
What do ribosomes do?
Site of translation
What do inclusions do?
reserve nutrients
What is the purpose of the chromosome?
stores the genetic material