Primerano Exam 1 Flashcards
(103 cards)
Zoonotic Infection
Exogenous microbes transmitted from animals to human
fomites:
inanimate objects which harbor the microorganisms, e.g. infants toys, shared toothbrushes.
Nosocomial infections.
Crowded conditions, poor sanitary practices, and impaired defense systems in hospitalized patients
Sterile tissues.
blood, deep tissue, and alveoli in lung.
bacteriocins
toxic bacterial proteins that kill other bacteria
Koch’s Postulates
1) The bacterium should be found in all people who have the disease. Also, the bacterium or its products should be found in parts of the body affected by the disease.
2) Bacterium should be isolated from the lesions of an affected person and able to be maintained in pure culture.
3) The pure culture, inoculated into a susceptible human volunteer or experimental animal, should reproduce the disease symptoms.
4) Same bacterium should be reisolated in pure culture from the infected animal or human.
Problems with Koch’s Postulates
1) Ignores the role of the host. Susceptibility and resistance can have a genetic basis and reduces the extent of correlation expected in postulate #1.
2) Fastidious organisms are harder to culture. Many organisms can’t be cultured at all.
3) Variability (in virulence) of a single bacterial species. Organisms can acquire new virulence traits by genetic exchange (e.g. lysogenic conversion).
4) We can’t ethically inoculate humans with dangerous/lethal for experimentation.
5) Polymicrobial infections.
Prokaryotes:
cells lack a membrane bound nucleus
Eukaryotes:
cells which have a defined nucleus
Bacteria are
unicellular prokaryotic organisms and as such lack a nuclear envelope as well as membrane-bound organelles.
cell wall
Fungi are
eukaryotic organisms which have a well-defined nucleus, membrane-bound cytoplasmic organelles and a cell wall
Fungi include
yeasts (unicellular), molds (multicellular and filamentous), and dimorphic fungi which can switch from yeast to mold.
Parasites (broad definition)
prokaryotic, eukaryotic or viral organisms that require a living host for at least part of their life cycle and cause disease to the host.
Parasites (narrow definition)
unicellular or multicellular eukaryotic organisms that require a living host for at least part of their life cycle and cause disease in the host.
Viruses are
intracellular parasites that lack cell structure; generally consist of nucleic acid genome surrounded by a protein coat; require a cellular host for replication.
Prokaryote Ribosome structure
70S Ribosomes (30S + 50S)
Prokaryote translation begins with
Translation begins with N-formylmethionine
Prokaryote respiration occurs where
Respiration occurs in plasma membrane
Viroid vs. prion
Viroids consist of RNA genome without any protein components
Prions are infectious agents consisting only of protein.
Flagella are required for what process?
movement of cell, toward a nutrient or away from a toxic substance, a process called chemotaxis
Flagella are composed of what protein?
flagellin
Pili (fimbriae) do what
thin, rigid appendages allow cells to adhere to host cell or other bacterial cell surfaces.
Pili (fimbriae) are composed of what protein?
composed of proteins called pilins;
Bacterial Capsule is made up of what?
Glycocalyx
