Lecture 1 Flashcards
Microorganisms are
Organisms that are too small to be clearly seen by the unaided eye
Range from microns to macroscopic
Relatively simple anatomy
Lack highly differentiated cells, lack tissues
Types of microorganism from most complex
Fungi
Bacteria
Viruses
(Prions)
Prokaryote
A single celled organism lacking a true nucleus and membrane bound organelles
Have cell walls (except for mycoplasma)
Eukaryote
Cells with a true nucleus
Membrane bound organelles present
Cells of higher organisms
Can be single-celled or multicellular organisms
Fungi
Kingdom Fungi includes moulds and yeast
Unicellular organisms
Can also exist as complex multicellular structures
Eukaryotic
Many have both asexual and sexual reproduction cycles
Examples:Bread mold,Penicillium, mushrooms, Ringworm
Bacteria
Domain Bacteria contains many bacteria kingdoms
Ubiquitous and some live in extreme environments
Prokaryotic
Majority have cell wall with peptidoglycan
Lack a membrane-bound nucleus
Asexual reproduction
Majority require 1000X magnification to be seen
Acellular Infectious Agents
Infectious “particles”
Are not cells
Have the ability to replicate, but only when they have infected a cell
2 categories of Acellular Infectious Agents
Viruses
Prions
Viruses are composed of
Genetic material material (DNA, RNA)
Protein capsule
Proteins and sugars for attaching to host cells
Lipid envelope layer
Viruses are
Many virus families
Cannot replicate on their own
1000 – 100,000X smaller than bacteria
Prions
Discovered by Stanley Prusiner in 1982
Infectious protein particle
Causative agent of the spongiform encephalopathies
Bovine spongiform encephalitis (Mad cow)
Scrapies
Different disciplines involving microbio
Advanced imaging
Culture techniques
Molecular biology
Genomics
Proteomics
Biochemistry
Bacteriology, virology, mycology,
Immunology
Binomial naming system
Official scientific name
Always give the Genus followed by species
Italicize (or underline) both the genus and species
Genus is capitalised; species is always lower-case
Etiology
The study of the cause of disease
Etiological agent
Whatever causes the disease
Can be a toxin, trauma, microorganism
Infection
Invasion and multiplication of organisms inside the body
Usually causes injury
Injury can be direct or indirect
Infectious
Capable of causing infection, capable of being transmitted by infection
Infectivity
The ability to enter and replicate in a host
Direct injury
When using in the context of an infection, refers to damage to tissues caused by the infectious organism
Ex. toxins produced by the bacteria
Indirect injury
When using in the context of an infection, refers to damage to tissues caused by the immune system
Host
An animal or plant on or in which a parasite or commensal organism lives
Example: in a case of a cold, a cold virus has infected a human host
Host cell
A cell that has been infected by a microorganism, most commonly by a virus
In the case of a virus infection, the host cell becomes the site of virus replication
Pathogen
A virus, bacteria, or other microorganism that can cause disease
Pathogenic
The ability to cause disease
