parasites Flashcards
definition of a parasite
organisms that live in/on another organism and obtain nourishment at the expense of the host (usually causes harm to the host)
(parasites) what is a primary host organism
where the adult forms of the parasite develop
(parasites) what is a secondary host organism
where larvae/intermediate forms of the parasite are found
(parasites) what is a vector
secondary hosts which actively and directly transfer the parasite from one primary host to another primary host
give an example of something that uses vectors
malaria
whats the proper name for an organism that lives IN a host
endoparasites
whats the proper name for organisms that live ON a host
exoparasites
give 2 examples of endoparasitess
pork tapeworm and beef tapeworm
(tapeworms) what is the head called and what is it’s adaptation
the scolex, has hooks and suckers to prevent it from being dislodged by peristalsis
(tapeworms) where is the head embedded
in the gut wall
(tapeworms) does it have a digestive system or mouth? why?
no digestive system or mouth as it only needs to absorb nutrients that have already been digested
(tapeworms) what’s the shape of their body - why?
flat to increase surface area or absorption of nutrients from the gut contents
(tapeworms) what is each proglottid covered in and why?
covered in thick cuticle, which is resistant to the action of digestive enzymes, also secrete mucus and enzyme inhibitors to reduce the risk of digestion
(tapeworms) what type of respiration do they do and why?
anaerobic as there is no oxygen in the gut lumen
(tapeworms) how would you describe each proglottid? what does it mean
a hermaphrodite (contains both male and female reproductive organs)
(tapeworms) what’s the impact of it being a hermaphrodite
it doesn’t need to find a mate as it can self-fertilise
(tapeworms) how many eggs does each proglottid contain and how does this help
50,000 – increases chance of infecting another host
what type of parasite is a headlouse
ectoparasite and obligate parasites
how do headlouse work
clings to hair on head by strong claws, eggs are laid and glued to base of hairs (when they’re empty they’re called nits)
what does an obligate parasite mean
they have no vectors or secondary hosts and transmission is by direct contact
can plants be parasitic? (example?)
yes, dodder - no leaves/roots
how is dodder adapted for being a parasite
has many suckers, which penetrate the xylem (to obtain water and minerals)
why is dodder an obligate parasite
it has no leaves, so cannot carry out photosynthesis, so needs to live on a host to survive
how would you describe mistletoe
semi-parasitic
