L33 Causes of Infection Flashcards
What is the simplest form of pathogen?
Virus
What are the 3 major components of a virus?
1) Genetic material (DNA or RNA)
2) Protein coat (capsid)
3) Lipid envelope (derived from host cell)
True or false: Viruses contain genetic information in chromosomes
False.
Genetic information in viruses is in the form of DNA or RNA, and is not in chromosomes.
True or false: Viruses contain genetic material, but no organelles
True
What is a biofilm?
A ‘hive’ of bacteria cells that work together to achieve greater things than they can do alone.
How can bacteria cells pass on genetic information?
Via plasmids
What are the geometric classifications of bacteria?
Round = cocci
Rods = bacilli
Spiral - spirillum
What are the bacteria classifications according to the ability of their cell wall to take up stain?
Gram negative
Gram positive
Others (e.g. mycobacteria)
What is the difference between gram positive and gram negative bacteria cell wall thickness?
Gram-positive have a solid, thick peptidoglycan cell wall – makes them very resilient.
Gram negative have thin peptidoglycan cell wall – makes them more susceptible to the environment.
How is gram negative bacteria stained?
Gram negative staining: The first stain is applied. Then an ethanol wash. The ethanol will dissolve the gram neg membrane and so the first stain is washed away, too. Then the second stain (pink) is applied and so only the pink stain remains in the end.
How is gram positive bacteria stained?
Gram positive staining: The first stain is applied. Then an ethanol wash. The ethanol partially dissolves the membrane but not all of it. Second (pink) stain is added, the mixture of the two stains makes a purple colour.
Meningococcal sepsis, cellulitis, and streptococcal throat infection are all caused by what?
Bacteria
Yeasts and moulds are are examples of what type of pathogen?
Fungi
What are ‘dimorphic fungi’?
They can switch between being moulds and yeasts
Candida albicans is an example of what?
Yeast
