week 2 sem 2 Flashcards
prokaryote vs eukaryote
prokaryote:small unicellular (structure) no membrane (cytoskeleton) , asexual reproduction
eukaryote: large, multicellular, have membrane, sexually reproduce
what is a microorganism
tiny living organisms
they are everywhere
- living organisms can reproduce independently thus virus and pirons are not living
virus
not living
no cellular strucure
protein capsule around DNA or RNA
can mutate
antibotics are ineffective
size= billionth of a meter
bacteria
prokarytoic
mostly unicellular
different shapes
have cell walls
protoza
eukaryotic cells
unicellular
usually motile (moves about)
bigger then bacteria
fungi
eukaryote
uni or multicellular
has cell wall
produce spores
helminths
eukarytoe
multicellular
large
eggs/ lava/ adult cycle
bacteria growth requirments
pathogenic bacteria= 37 degrees
pH 7
oxygen/ no oxygen
gram positive
tijick layer of peptidoglycan as cell wall
capable of forming spores (survive in extreme conditions)
reinfection
gram negative
reinforced with 2nd membrane as cell wall
most difficult to kill
produce endotoxins (released when bacteria dies)
normal flora benefits
skin: reduces pH
oral & vagina: competes and inhibits pathogens and yeast
intestine: excrete antibacterial chemicals, synthesis and secrete vitamins, stimulate local immunity
normal flora disadvantages
compete for nutrients
bacterial synergism
endogenous diseases: fever inflammitary
opportunistic infection
normal flora oppoutunistic infection causes
genetic predistibutions
chemo/ impacted immunity
HIV/AIDS
bone marrow disease
pregnancy
mode of transmission
contact either directly or indirectly
vehicle eg air water food
vector eg via an animal (mosquitoes and ticks)
formite-borne via an inanimate object
verticle= intrauterine and postpartum
enviornmental control- sterilisation
destruction/ elimination of ALL microbes
methods= heat, heat + pressure, radiation, filtration, chemical
chain of infection
infectious agent
reservoir
portal of entery
mode of transmission
portal of exit
suseptible host
enviornmental control- disinfection
elimination of MOST pathogens from inanimate objects
methods= chemical, gas
sanitation is
safe disposal of human urine and feaces
To cause disease, a pathogen must successfully achieve four steps
exposure, adhesion, invasion, and infection
Pathogenicity
the ability of a microbial agent to cause disease
Virulence
the degree to which an organism is pathogenic
Adherence
Adhesion is the capability of pathogenic microbes to attach to the cells of the body using adhesion factors
Found on the surface of certain pathogens and bind to specific receptors on host cells
Toxins
biological poisons that assist in their ability to invade and cause damage to tissues.
Invasiveness
invasion is the ability of a pathogen to enter host cells or tissues, spread and cause disease