what are the 3 methods of disease transmission
- direct
- indirect
- vector
inhaled airborne particles can cause diseases in humans, both viral and bacterial; name some viral diseases (7)
- chickenpox
- flu
- measles (rubella)
- german measles (rubella)
- mumps
- smallpox
- coid 19
inhaled airborne particles can cause diseases in humans, both viral and bacterial; name some bacterial diseases (5)
- whooping cough
- meningitis
- diphtheria
- pneumonia
- tuberculosis
how does bacterial conjugation happen
(exchange of genetic information by ‘mating’)
- donor cell attachess with its pilus
- cells contact one another
- one strand of plasmid DNA transfers
- recipient synthesizes complimentary strand to become an F+ cell, as does the donar cells to restore its complete plasmid
what is in a bacerial spore
mainly the genes only
how are bacteria classified
- by membrane
- shape
- utilisation of oxygen
- spore producing
how does the membrane differ in gram -/+ bacteria
- gram+ bacteria have a thick prptidoglycan membrane
- gram- bacteria have a thin peptidogylcan layer with an additional outer membrane
what is the OM of a G- bacteria made of
lipids and proteins, and lipopolysaccharides
what does lipopolysaccharide do to humans
it is pathogenic
free LPS in solution is toxic (endotoxin)
what are the 2 main pathogenic factors
- the ability to invade tissues
- the ability to produce toxins
bacteria can invade tissues using certain enzymes - give 3 examples
- hyaluronidase - strep, staph and clostridia
- collagenase - clostrisium
- streptokinase & staphylokinase - strep & staph respectively
how do bacteria evade host defences (6)
- remain inaccessible to phagocytes
- avoid provoking an overwhelming inflammatory response
- inhibit phagocyte chemotaxis
- disguise the antigenic surface of the cell
- avoid engulfment
- survival inside the phagocyte
define:
* exotoxin
* endotoxin
- exotoxin: an unbound toxin milecule secreted by a living cell
- endotoxin: released after the pathogen is dead
