Protista.notebook March 07, 2012
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KINGDOM PROTISTA Most protists are freeliving
Some can cause disease (ex. Malaria is caused by Plasmodium vivax)
Some are autotrophs, some heterotrophs
Most are single celled, some multicellular.
All are eukaryotes
Grouped together because they don't fit well anywhere elseNot as diverse as Bacteria or Archaea, but more than others.
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Classifying Protists
Protists are grouped into 3 main categories
1. PROTOZOA animallike, heterotrophs that ingest or absorb their food.
2. ALGAE plantlike, autotrophs that photosynthesize
3. SLIME MOULDS funguslike heterotrophs
Protista.notebook March 07, 2012
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1. Protozoa
30000 species Live in aquatic environments, moist soil or the fluids of
other organisms! 10000 species cause disease. (African Sleeping
Sickness, ) 4 main groups:
a. Flagellates (One or more flagella)b. Sacrodines (Produce limblike structure called
pseudopodia)c. Ciliates (covered in cilia)d. Sporozoans (form spores at some point in life
cycle)
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We will look at 2 representative Protozoa.
The phylum Sarcodina is also known as AMOEBAE. (singular amoeba)
One organism within this phylum is Amoeba proteus
SARCODINES
Protista.notebook March 07, 2012
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Amoebas are unicellular organisms that move by flowing their cell contents into projections called PSEUDOPODIA (falsefeet)
Some also have flagella
Contractile vacuole
Phagocytic vacuole
Nucleus
Endoplasm
Ectoplasm
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Amoebas feed by PHAGOCYTOSIS, which is is the cellular process of engulfing solid particles by the cell membrane.
Protista.notebook March 07, 2012
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Reproduction is ASEXUAL
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CILIATES
The most famous example from the CILIATES is Paramecium caudatum
Ciliates move by rhythmic beating of cilia.
Protista.notebook March 07, 2012
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Ciliates feed by sweeping a stream of particle laden water into their "mouth" and "gullet".
Food vacuoles (phagocytic vacuole) at the base of the gullet fill and move into the cytoplasm.
Indigestible particles are discharged by EXOCYTOSIS.
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Ciliates anatomy:
Macronucleus runs all metabolic processes. Mirconuclei responsible for sexual reproduction. Contractile vacuole used to maintain fluid balance
Protista.notebook March 07, 2012
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Oral groove
Contractile vacuole
Cell mouth GulletPhagocytic vacuole
Macronucleus
Micronucleus
Cilia
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Reproduction is both asexual and sexual
Asexual is by fission.Sexual is by conjugation
Both are similar to bacteria, but in conjugation, a CYTOPLASMIC BRIDGE forms and micronuclei are copied and fused.
Protista.notebook March 07, 2012
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Unlike bacteria, that have a cell wall to protect them from bursting, protozoa do not.Therefore a mechanism to move water into and out of the cell is required.Here is the problem:
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Contractile vacuoles are used to pump water out of the cell as the Paramecium lives in a hypotonic solution.