Unicellular eukaryotes/ Phylum Porifera (Sponges) Flashcards
(37 cards)
Ectoplasm
- gel like, plasmagel that provides structure
- Filamentous actin
Endoplasm
- fluid like, plasmasol
- Globular actin
Filopodia
- much slimmer than lobopodia, contain only ectoplasm and lack hyaline cap
Reticulopodia
- elaborate, extremely think filaments that branch and coalesce (extends and reduces) repeatedly in highly complex patterns
Autotrophs
- can synthesize their own food
- they do not eat other organisms or substances derived from them
Heterotrophs
- obtain organic molecules synthesized by other organisms
phagotroph (holozoic)
- ingest visible particles
- phagocytosis and endocytosis
- LOBOPODIA extended around particle
** Amoebas use lobopodia for feeding
osmotroph (saprozoic)
- ingest soluble food
- you can’t see the food because it is already dissolved in water
- pinocytosis
- endocytosis
Why are autotrophs flexible?
- they have chloroplasts and can perform photosynthesis
Euglena viridis
- Normally photoautotrophic
- contain chloroplasts
- WHEN THEY ARE KEPT IN DARK, IT BECOMES OSMOTROPHIC but they are norMally PHOTOAUTOTROPH!!!!
Feeding Mechanisms of Unicellular eukaryotes
- Didinium
- Stentor
- Suctorian
Didinium
Free living ciliophoran that uses a non-ciliated cytopharynx (nose) to engulf prey. A voracious predator of paramecium.
Stentor (Vorticella)
Free-living ciliophoran that transforms into a horn like structure. Utilizes cilia to generate feeding current towards horn
Suctorian
Sessile. Utilizes tentacles to snag
other protozoans and suck their cytoplasm.
- THEY JUST SIT AND WHEN SOMETHING MOVES AROUND, THEY TRAP THEM
- tentacles are hollow
- the knobby tips of the
tentacles have an opening and
contain haptocysts
EXOCYTOSIS
- EXCRETION
- Elimination of undigested material within digestive vacuole occurs via fusion with cell surface
PASSIVE DIFFUSION
-EXCRETION
- Metabolic wastes (eg., end products of nitrogen metabolism, such as ammonia) diffuses across cell membrane
CYTOPROCT
- EXCRETION
- Permanent excretory pore (usualy stays in one place)
- Waste material accumulates in a vacuole adjacent to the cytoproct and is periodically discharged (eg., in ciliates)
Contractile vacuole
commonly found in freshwater unicellular eukaryotes and generally absent in marine/ parasitic forms
-dilution in cytoplasm by loss of ion and osmosis leads to death, so;
- they are more found in freshwater unicellular eukaryotes because contractile vacuoles collect excess water and pumps it out of the cell
Hydromineral balance is regulated by?
specialized organelles called contractile vacuoles
What does filling and expulsion rates depend on in Osmoregulation?
- organism size (contractile vacuole is faster in smaller organisms
- ionic/osmotic gradient
What are Phylum Porifera (Sponges)?
- They are sessile multicellular organisms with no organs.
What are Filter feeders?
In Sponges (Phylum porifera), it is a SYSTEM OF CANALS through which water is pumped into the body and food particles collected.
- possess functionally distinct cell types
What are the distinct cell types of Phylum Porifera (Sponges)?
- Choanocytes
- Archeotypes
- Secretory cells
Choanocytes (pass down food vacuoles)
In Phylum Porifera (Sponges), they are responsible for collecting food.
- THEY ARE FEEDING BY FILTERING PARTICLES OUT OF WATER.
- Ovoid cells that line canal system and chambers
2 parts:
- exposed end (a collar forming a filtering device)
- embedded end
- flagellar motion pulls water through a “filter”
