Chapter 11: Unicellular Eukaryotes- Protozoan Groups Flashcards
Protozoan characteristics?
lack cell wall
at least one motile stage in life cycle.
most ingest their food
carry all life activities in a single cell
survives only in narrow environment ranges
Unicellular eukaryotes are the major cause of?
disease
Symbiotic?
a close prolonged association between two or more different organisms of different species.
Mutualistic?
both species benefit in the relationship
Commensalistic?
benefits one but the other is not harmed
Parasitic?
1 benefits and another is harmed
Heterotrophic?
protozoa obtain organic molecules synthesized by other organisms
Phagotrophs?
feed on visible particles
Osmotrophs?
feed on soluble foods
Mode of nutrition for unicellular organisms is often ?
variable and opportunistic
Major Characteristics!
unicellular mostly microscopic no germ layers no organs and tissue, just organelles varied forms of nutrition varied forms of locomotion asexual and or sexual reproduction
Types of locomotion?(3)
cilia, flagella and pseudopodia
Cilia and Flagella
morphologically the same but cilia is smaller whereas flagella is long…more tail like
Pseudopodia ?
endoplasm?
Ectoplasm?
endo- contains nucleus and cytoplasmic organelles ecto- more transparent (hyaline) contains bases of cilia or flagella more rigid appears granular
Types of Pseudopodia- Offer descriptions of each: Lobopodia Filopodia Reticulopodia Axopodia
- large blunt extensions of the cell body containing both endo and extoplasm.
- thin extensions usually branching and contain only ectoplasm.
- repeatedly rejoin to form a netlike mesh…which makes it distinguishable from filopodia.
- long, thin pseudopodia supported by axial rods of microtubules which are organized in a spiral or geometrical array….which can be extended or retracted via addition or removal of microtubules..progression via rolling motion aka….retraction of front and extenuation of the back…cytoplasm can flow along axonemes.
Limax??
movement of the entire body via pseudopodial movement…not individual movement of each extension.
Describe the process of pseudopodial movement. (theres a lot to know)
hyaline cap?
ABP?
endoplasm? myosin? actin??….
endoplasm flows into / toward the hyaline cap (ectoplasm extension) which contains actin subunits attached to regulatory ABPs which prevent actin from polymerizing…As the endoplasm flows and spreads to the periphery..interactions between phospholipids in the cell membrane causes the release of actin from their ABP allowing them to polymerize into actin filaments…which are cross linked via ABP causing the ectoplasm to become a tube with which the endoplasm can flow through as the pseudopodium extends. The trailing edge contains calcium ions that activate the release of ABP which releases the actin filaments permitting myosin to associate with and pull these filaments…causing contractions…creating a pressure that causes the endoplasm to flow back to the hyaline cap.
Excretion and osmoregulation is done via??(2)
Excretion of metabolic wastes is by diffusion…end product = Ammonia
Contractile Vacuoles- fill up and empty to maintain osmotic balance….water enters via osmosis.
Why do fresh water species have more contractile vacuoles and occur more frequently vs marine species??
Marine species cytoplasm is nearly isotonic to that of the marine environment…whereas freshwater species are hypotonic to their environment and continually need to expel water or else they would fill up and burst..
What are the three types of asexual reproduction found in unicellular organisms?
Fission
Budding
Multiple Fission(Schizogony)
Fission?
produces more individuals than other forms of production……binary fission is the most common…two identical individuals are produced via splitting of the cell..
Budding?
occurs when a small progeny cell (bud) pinches off from the parent cell and grows to adult size. **mostly ciliates
Multiple Fission?? (Schizogony)
Cytokinesis preceded by several nuclear divisions….thereby many individuals are produced simultaneously …
Sporogony ?
if the union of gametes precedes multiple fission or associated this occurs.
