Microorganisms Flashcards
What is a Protozoa?
Single celled organisms without a cell wall (mostly) and some move around freely
What is an example of a Protozoa?
Plasmodium spp.
Transmitted by mosquito (vector) and infects RBC in humans
Causes malaria
What is a microorganism?
Microscopic organism
Mostly unicellular
Eg bacteria, fungi, Protozoa, algae abs viruses
What are fungi?
Microorganisms that are generally non motile with cell walls
What are fungus cell walls mostly comprised of?
Chitin
What are moulds?
Multicellular
Composed of cells arranged in branching filaments- hyphae
What is yeast?
Unicellular microorganisms
What is the function of spores?
Produced by fungi
Utilised by fungi to reproduce
What is immunosuppression?
When the host has a weakened immune system
What does bacilli mean?
Rod shaped bacteria
What are cocci?
Sphere shaped bacteria
What does spirochetes mean?
Spiral shaped bacteria
What does diplo mean?
Two bacteria are joined together
What does strepto mean?
Chains of bacteria
What does staphylo mean?
‘Grape-like’ clusters of bacteria
What does gram positive and gram negative relate to?
Whether bacteria retain a stain when the grab mmm stain technique is applied
What is Gram positive bacteria?
Retain the stain
Result of high levels of peptidoglycan in their cell walls
What is gram negative bacteria?
Do not retain the stain
Smaller concentrations of peptidoglycan in their cell wall
What is binary fission?
How bacteria reproduce
Divide into 2 once they have doubled their size and replicated their chromosomes
Asexual process
What are the major components of a bacteria cell?
1) has a cell wall and usually capsule/slime layer outside of this
2) cell (plasma) membrane
3) do not have membrane bound organelles
4) have ribosomes
5) pili present to enable attachment to surfaces
6) singular circular molecule of DNA (nucleoid) found in cell cytoplasm
What is vegetative bacteria?
Growth and reproduction form of the bacteria
What happens to bacteria when conditions become unfavourable?
Resistant to desiccation, extreme temp. and many chemicals
Some produce spores- survive extreme environmental conditions
Spores remain viable- only germinate once conditions become favourable
Eg clostridium difficile
What she’s commensal organism mean?
Bacteria benefit from host environment while host is neither harmed nor benefited
What does normal flora mean?
Populations of organisms that live in various parts of the body but don’t cause disease
What does pathogen mean?
Parasite that can cause disease
What does mutualism mean?
Both microorganism and host benefit from living together
What are the 5 characteristics of viruses?
1) generally smaller than bacteria
2) contain small amounts of nucleic acid (DNA or RNA)
3) genome surrounded by protein coat (capsid) which protects it
4) viruses may be enveloped or non-enveloped
5) many shapes- helix, spiral, cuboid and icosihedral
What are prions?
Infectious proteins
They are extremely hardy and resistant to disinfection,m, heat etc
Antivirals/antibiotics have no effect
Infectious form of protein causes diseases eg new variant Creutzfeldt Jacob disease (CJD)
