Module 1 Flashcards
Can microorganisms be seen without aid of a microscope?
No
How big are microorganisms?
Smaller than 0.1mm
What are microorganisms?
Simple, unicellular organisms
What are some other names for microorganisms?
Bugs, germs, microbes
What are the 4 groups of microorganisms in order from largest to smallest?
1) Protozoa
2) Fungi
3) Bacteria
4) Viruses
What are protozoa?
Unicellular animals that move with flagella or ameboid motion, they each have a nucleus and plasma membrane.
Where do protozoa live and what do they feed on?
Live in soil and water
Feed on bacteria and small particles
What is an example of a protozoa?
Giardia - causes “bever fever” which leads to diarrhea
What is fungi?
Non-photosynthetic plants
What make up a fungi cell?
Nucleus and rigid wall.
How are fungi divided?
Yeast and mold
What is yeast?
Type of fungi that is unicellular
What is mold?
Type of fungi that is multicellular that starts out as a tube structure that produces spores that appear grey blue, green or black.
What is an example of a fungi?
Candida - causes oral yeast infections, yeast vaginitis, skin infections, yeast diarrhea following antibiotic therapy.
What is bacteria?
unicellular organisms lacking an organized nucleus surrounded by a rigid wall.
What type of microorganism is “ubiquitous” and what does this mean?
Bacteria
Found everywhere there is moisture and nutrients.
What is an example of bacteria?
Streptococcus - causes strep throat
Staphylococcus - causes staph infection (boils)
Salmonella - food poisoning
What are viruses?
The smallest microorganism, they rely on a living host such as an animal, plant or bacteria to replicate.
What does a virus cell consist of?
DNA or RNA surrounded by a protein coat and sometimes a lipid coat.
What is an example of a virus?
Influenza, hepatitis, rabies, AIDS
How are microorganisms measured?
Micrometer = 1/1000 mm
What are round bacteria?
Cocci (coccus)
What are rectangular bacteria called?
Rods/baccii
bacillus
What are spiral/curved bacteria called?
spirillum
What is Gram?
Staining bacteria to:
identify type (by shape and colour of gram)
determine effectiveness of antibiotics
determine effectiveness of disinfectants
What colour is gram positive?
Dark blue
What colour is gram negative?
Red
What are the three types of bacteria?
Cocci
Rods/bacilli
Spirilla
What are endospores?
Gram postitive bacertia (rods) that are able to produce a spore within the cell under adverse conditions (dry, cold, no nutrients).
What are vegetative cells?
Bacterial cells that do not contain endospores or have not yet begun to grow them.
What is sporulation?
Takes place in an endospore when certain nutrients are depleted, genetic material is enclosed in compact layers of spore coat and may lie dormant for days/months/years.
Describe the cycle of an endospore’s life?
Vegetative cell –> (adverse conditions) –> Endospore –> free spore –> + H20 and food –> germination –> vegetative
What are some examples of endospores?
Anthrax,
gangrene,
tetanus
What are endospores resistant to?
Heat, disinfectants, cold, ultraviolet light, acids, alkalis, detergents.
How do bacteria reproduce?
Binary fission.
Cell elongates, genetic material replicates and moves to separate ends, cell divides.
What is generation time?
Time it takes for binary fission to occur (doubling of population), related to the time it takes to cause disease.
What is the generation time of a standard bacteria?
15-30 mins
What is a colony?
A visible mass of bacteria on a culture media, shows all the descendants of a single bacterial cell (clone).
What are the 4 stages of the bacterial growth curve?
1) Lag - Adapting to new environment
2) Log - Max reproduction
3) Stationary - no change in #, less food, more waste
4) Death - spores may form
What is the incubation period in bacteria growth?
Period of time after an introduction of a microorganism to a host, no disease symptoms and is connected to the lag cycle.
What is the acute period in bacteria growth?
Onset of symptoms, connected to the log cycle.
What is the stationary stage of bacteria growth?
Symptoms are no worse but no sign of recovery
What is the convalescent period of bacteria growth?
Symptoms subside, connected to the death phase.
What are type of virus is easier to kill with disinfectant?
Lipid viruses (except for Hepatitis B)
What are influenza A?
Viruses responsible for pandemic outbreaks (H1N1, spanish Flu, Swine flu) high death rate.
What are influenza B?
Viruses that cause local outbreaks
What are colds caused by?
Rhinoviruses
Describe the multiplication of a virus
- Attachment to host
- Penetration
- Viral Replication
- Viral Assembly (Nucleic acid, protein coat)
- Release from host
What are oncogenic viruses?
Viruses that transform cells into tumour cells
How do viruses effect the host cell?
Usually kill it
- lysis
- diversion of metabolic pathways
- destroyed by host’s lymphocytes
How do antibiotics effect viral replication?
No effect because antibiotics are directed against metabolic pathways of bacteria and viruses don’t have any of their own.
What are some anti-viral drugs?
Acyclovir (genital herpes)
Zidovudine ( AIDS)
Immunization
What is a problem in developing antiviral drugs?
It has to kill the virus but not the host cell.
