Protista, eg. Amoeba Flashcards
3 protista characteristics
-contain single celled and simple multi-cellular organisms
-they are eukaryotic- they have a membrane enclosed nucleus and membrane enclosed organelles
-some feed by taking in organic substances, others can photosynthesise
three examples
-amoeba
-algae
-paramecium
4 amoeba
-moves by means of pseudopods and is well known as a representative of unicellular organisms
-consists of a single cell
-consumer
-it lives in freshwater ponds (mud at bottom)
algae
a large and diverse group of plant like organisms ranging from unicellular to multicellular forms
paramecium
consist of a single cell yet are visible to the naked eye
what is an amoeba made up of?
cytoplasm, ectoplasm and endoplasm
cell membrane- semi-permeable
nucleus
waste products
pseudopod
fat droplets
food vacuole
contractile vacuole
endopalsm
fluid like, grainy in appearance due to the presence of food vacuoles and waste materials – in middle of the cell
ectoplasm
can become soft in places to allow the development of pseudopodia –on the outskirts
pseudopods
are referred to as false feet as they are produced at any point on the body and have no fixed position
development of pseudopod
-extend in the direction amoeba wishes to move
-develop when the ectoplasm softens and moves forward and the endoplasm moves in to replace it
-used to engulf prey
food vacuoles
amoeba feeds by surrounding its prey with pseudopodia and secreting digestive enzymes into the vacuole created
food can then be stored within the vacuole
contractile vacuole- how it works
-due to osmosis, water rushes into the amoeba
-contractile vacuole swells and moves to the edge of the cell
-bursts and expels the water
-cycle repeats
why is contractile vacuole necessary?
responsible for osmoregulation- without it amoeba would expand and burst
