Transcript Biology CP- Protists

Algae- Plant- like Protists
Textbook 17.4
pp. 390-394
Plant –like Protists- Algae
AutotrophsPhotosynthetic- chloroplasts-supply O2
Classified by:
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Type of cell wall
Pigments
Structure
Storage carbohydrates
Reproduce asexually and sexually
Most are unicellular; some are colonial and
multicellular
Euglena
Euglenoids
Single celled
Photosynthetic
One or two flagella
Lack cell wall
Live in freshwater
Example- Euglena- can be both an autotroph
and a heterotroph.
B. Dinoflagellates
Single-celled; found in fresh and salt water.
Cellulose cell wall.
Two flagella.
Plankton- surface of ponds, lakes, oceans
Serve as basis of aquatic food chains.
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Phytoplankton- photosynthetic
Zooplankton- non-photosynthetic protozoans
Algae blooms- population explosion due to excess
nitrates.
Red tides
Toxins deadly to fish and humans
Pfiesteria- bleeding sores in fish; neurotoxin affects
humans
Bioluminescent- some produce light.
C. Diatoms
Single-celled algae found in fresh & salt water.
Glass-like cell wall of silicaMany different refractile shapes
All contain chlorophyll; but other pigments
Many colors of brown or yellow.
Impt. Food source for marine animals.
Float near the surface- oil reserves.
When diatoms die; sink and fossil remainsdiatomaceous earth are mined.
Uses- grinding/polishing products, filter materials,
toothpaste.
D. Seaweeds
Large multicellular algae
Not plants- No true roots,stems, or leaves.
All have chlorophyll.
3 groups based on pigments/ color.
Brown algae- Kelp- biggest- up to 60 m.
Red algae- tropical- deepest waters; 1 type=agar.
Green algae- evolutionary ancestor of plants.
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Single- celled- Chlamydomonas with 2 flagella
Colonial- Volvox ( 100-1000s of cells moving in
unison)
Multicellular- filaments- Oedogonium, Spirogyra
Seaweed Uses-
Fungus-like Protists
Textbook 17.3
pp.387-389
Fungus-like Protists
A. Slime “molds”
Not true molds which are fungi
Decompose dead organic mater
2 types:
Plasmodial Slime MoldsCellular Slime Molds
1. Plasmodial Slime Molds
Plasmodium- mass of cytoplasm ,no
membranes , no cell walls, many nuclei.
Giant supercell ,streaming cytoplasm –
amoeba like.
Life Cycle Limited resources- reproductive
structures- fruiting bodies (sporangia)
formed.
 Sporangia release haploid spores.
 Better conditions- haploid spores fuse
into diploid zygote.
 New plasmodium develops.
2. Cellular Slime Molds
Unicellular and Multicellular stages
Individual, colony, and spore stages.
Asexual and Sexual reproduction.
Scarce food- cells stick together
Slug-like colony
Trail of slime
B. Water molds- Oomycota
Freshwater.
Decomposed dead plants,animals.
Parasitic forms- skin or gills of fish.
Unicellular or multicellular
Sexual reproduction- egg cell
Downy molds
Reproduce sexually- egg cell
Spores- wind blown
Plant parasites
Irish potato famine –mid 1800s
Example of effects of clones
 Lack of genetic variation
Water and Downy moldsDNA studies
More closely related to plant-like protists
(algae)
Evolution
Textbook 17.5
pp. 395-397
Evolution hypothesis
Protists evolved from ancient prokaryotes
Animals, Plants, and Fungi evolved from
animal-like, plant-like, and fungus-like
protists
2 main processes-explain complex
eukaryotic cell.
Infolding
Endosymbiosis
Infolding:
Inward folding of cell membrane of bacterial
cells
Produced internal membranes of eukaryotic
cells:
nuclear membrane, endoplasmic reticulum,
golgi apparatus.
Eukaryotic Cell- separate compartments for
chemical reactions.
Endosymbiosis:
Explains mitochondria & chloroplasts
Phagocytosis of smaller bacteria into a host cell
resulting in a symbiotic relationship.
Mitochondria- engulfment of aerobic bacteria.
Chloroplasts- engulfment of photosynthetic bacteria.
EvidenceMitochondria & chloroplasts are similar to bacteria
Contain DNA, RNA & ribosomes.
Replicate their DNA and reproduce by binary fission.
Giardia have no mitochondria.