Microbiology (11) Flashcards
What is binomial nomenclature?
> Established in 1735 by Carolus Linnaeus
Uses latin
Each organisms have 2 names- a genus and a species
Genus- 1st name and it always capitalised
Species- 2nd name and is not capitalised
Where do the names come from for binomial nomenclature?
1) Describe an organism
2) Honour a researcher
3) Identify the habitat of an organism
What is microbiology?
> The scientific study of microorganisms
They are very small so can only be seen with a microscope
It is 1/ a few cells (germs or microbes)
Frequently studied as populations containing large numbers of individuals
What is an organism?
A complete living unit capable of an essentially independent/autonomous existence
What is a macroorganism?
> Plants or animals
> Thousands/millions/billions of cells
What are the 2 main classifications of organisms?
Eukaryotes and prokaryotes
What are eukaryotes?
> Have a complicated cell structure
Includes vertebrates, invertebrates, seed plants, ferns, mosses, algae
Also includes fungi and protozoa
What is fungi?
> Yeasts and mould
Do not have chlorophyll
Feed on living plants, animals and decaying matter
Examples include athletes foot (Tinea pedis) and ringworm (tinea capitis)
What is protozoa?
> Feed on dead organic matter
> Examples include malaria (plasmodium vivax) and sleeping sickness (trypanosoma brucei)
What are prokaryotes?
> Simple structured
> Includes bacteria
What is gram staining?
> Under microscope, bacteria are colourless so to see them, they are stained with a dye
Usually methylene blue
Gram +ive retain dye- violet e.g. staphylococcus aureus
Gram -ive lose stain- pink e.g. eschericia coli
What is morphology?
> The classification of bacteria into 4 groups, according to their shape
1) Coccus (round)
2) Bacillus (rod shaped)
3) Coccobacillus (very short rods)
4) Spirochaetes- spiral
What is the oxygen requirement of bacteria?
> Some bacteria need oxygen in their environment to grow- obligate aerobes
Some cannot tolerate the presence of oxygen- obligate anaerobes
Some can grow with or without oxygen- facultative anaerobes
What is mycoplasma?
> Type of bacteria
Do not have cell walls so they do not have a fixed shape but they can produce filaments that resemble fungi
Mycoplasma pneumoniae can cause a common form of mild pneumonia
Due to their shape, they are naturally resistant to antibiotics
What is the relationship between rickettsia and chlamydia?
> Grouped together as they are both obligate intracellular parasites- reproduce only in a mammalian cell
Rickettsia are fragile and transfer to humans often involves arthropods such as ticks
Chlamydiae are smaller- pelvic inflammatory disease, non-specific urethritis, sexually transmitted infections
What are viruses?
> Smaller than other microorganisms
Not whole cells so can only reproduce by entering cells of living organisms and redirecting the metabolism of these cells by substituting their own nucleic acids for the cell’s DNA (obligatory intracellular parasites)
Infection by virus may result in the death of the host cell or they cell may not be killed but be transformed to become malignant
Some do not affect the functioning of the cell but may remain latent, but still potentially infective, waiting for the right conditions to reappear
Examples include herpes simplex, HIV, hepatitis, etc
What is Ebola virus disease (EVD)?
> A severe, often fatal disease in humans
Transmitted to people from wild animals and spreads in human population through spread of body fluids
Average EVD case fatality is about 50% but rates have varied from 25-90% in past outbreaks
First appeared in 1976
The outbreak in West Africa (2014) is the largest and most complex outbreak so far
Fruit bats are the natural host
Introduced to human population through close contact with body fluids from infected animals e.g. chimpanzees, gorillas, fruit bats, etc
Individuals are infectious for up to 7 weeks after recovery
Incubation period 2-21 days
Symptoms include fever, fatigue, muscle pain, headache, sore throat, vomiting, diarrhoea, rash, impaired liver and kidney function and external bleeding e.g. from gums or stools
What is the zika virus?
> Spread by Aedes mosquitoes
Name comes from the Zika forest of Uganda
First isolated in 1947
Virus is related to the dengue, yellow fever and Japanese encephalitis
Spread across to the Americans in 2015/16 resulting in the Zika virus epidemic
Symptoms include very mild symptoms including fever, red eyes, joint pains and headaches
No treatment and no cure
No reported deaths
Infection during pregnancy can cause microcephaly and other brain malformations in infants
