heterotrophic nutrition Flashcards
what are heterotrophic organisms?
digest the organic compounds produced by other organisms then
use the PRODUCTS OF DIGESTION to synthesise their own complex organic molecules
heterotrophic organisms need food sources that contain complex organic chemicals as sources of:
source of energy
carbon- making their own organic chemicals
nitrogen- making proteins and nucleic acids
phosphate - for ATP, phospholipids, nucleic acids
vitamins and minerals- making biochemicals
what are the forms of heterotrophic nutrition?
saprotrophic
parasitic
holozoic
what is saprotrophic nutrition ? (saprobiont / saprophyte)
EXTRACELLULAR enzymes are secreted from the organism which then digests what the organism is growing on
PRODUCTS OF DIGESTION are then absorbed and used as their source of energy and raw materials
what are examples of saprobionts
fungi
bacteria
what is parasitic nutrition?
parasites live on a HOST
and obtain nourishment at the EXPENSE of the host
they usually do harm to the host
what are examples of parasites?
lice
tapeworm
ticks
what is the scolex?
head of the tapeworm embedded in the gut wall and has hookers and suckers to prevent it being dislodged by peristalsis
why are their hooks and suckers on the scolex?
to prevent the scolex from being dislodged by peristalsis
why does a tapeworm have no digestive system or mouth ?
the tapeworm only needs to absorb nutrients that has already been digested
why does tapeworm have a flat body?
increase surface area for absorption of nutrients that have already been digested
what is the role of the proglotid being covered in thick cuticle
it is resistant to the action of digestive enzymes
it secretes mucus and enzyme inhibitors to reduce the risk of digestion
what is the advantage of each proglotid being hermaphrodite( both male and female reproductive parts)
it doesnt need to mate it self fertilises
so each proglotid produces around 50,000 eggs which increases the chance of INFECTING the host
what are the features of the ptoglotids on tapeworm?
surface is covered with hair like structures called MICROTRICHS
each is hermaphrodite
thick cuticle
what are the adaptations of tapeworm
scolex with hooks and suckers
no digestive system or mouth
flat body
proglotid covered in thick cuticle
each proglotid is hermaphrodite
parasitic nutrition steps
how it happens ( hosts and vectors)
primary host organism is where adult forms of the parasite develop
secondary hosts are where larva/ intermediate forms of the parasite are found
vectors- secondary hosts which actively and directly transfer one parasite from 1 primary host to another
where do adult forms of a parasite develop?
in a primary host
what is a vector?
secondary hosts which actively and directly transfer one parasite from 1 primary host to another
where are larval/intermediate forms of the parasite found?
secondary host
what is symbiosis/mutualism?
many organisms live in or on other organisms in a relationship that proves benefit for both organisms
what is the lifecycle of pork and beef tapeworms
1) eggs released into environment in fecaes
2) secondary hosts eat vegetation that is contaiminated with tapeworm eggs
3)eggs hatch and larvae burrow through gut wall - carried by blood
4) larvae develop into cycsts in muscle
5) humans eat undercooked or raw meat and get infected
6) scolex develops and attached to the walls of small intestine
7) adults grow to 5cm longer and can survive for many years
how do the secondary hosts e.g cow get the tapeworm?
1) eggs released into environment in fecaes
2) secondary hosts eat vegetation that is contaiminated with tapeworm eggs
3)eggs hatch and larvae burrow through gut wall - carried by blood
4) larvae develop into cycsts in muscle
how does the tapeworm transfer to the human?
A human eats undercooked or raw meat and gets infected
the scolex of the tapeworm develops and attaches to the wall fo the small intestine
what is holozoic nutrition?
ingestion and digestion of a food source
an organism doesnt need to stay attched to the food source in order to digest the food
it can ingest and digest somewhere else
PRODUCTS OF DUGESTION ARE ABSORBED AND ASSIMILATED - waste is egested
