Unit 6--Microbiology Chapter 20 Protists. Endosymbiotic theory Heterotrophic bacteria have plasmids...
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Transcript of Unit 6--Microbiology Chapter 20 Protists. Endosymbiotic theory Heterotrophic bacteria have plasmids...
Endosymbiotic theory
• Heterotrophic bacteria have plasmids (DNA loop) & simple ribosomes in their cytoplasm
• Mitochondria have circular DNA & bacteria-like ribosomes
• So…Eukaryotic cells may have engulfed prokaryotic cells & by mutualism created the “first mitochondria.”
• Autotrophic bacteria are Cyanobacteria with chlorophyll
• So, Eukaryotic cells may have engulfed prokaryotic cyanobacteria & by mutualism created the “first chloroplast.”
Characteristics
• Mostly unicellular
• Eukaryotic cells
• Most diverse kingdom:– Photosynthesis, like plants (algae)– Ingest food, like animals (protozoans)– Absorb food, like fungus (slime mold)
Classifying protists
PROTIST
Protozoan Algae Slime mold
heterotroph autotroph saprobe
Consume Produce Decompose
Animal-like Plant-like Fungus-like
DNA evidence shows that some archaebacteria may have been ancestors of protists.
Phylum…example…distinguishing characteristics
• Zoomastigina…Trypanosome
• Causes Sleeping sickness
• All are flagellated• Other examples
include those living symbiotically within termite intestine
Phylum…example…distinguishing characteristics
• Rhizopoda…ameba• Moves by
pseudopods = cytoplasmic extensions
• Feed by phagocytosis = surrounding & engulfing
Phylum…example…distinguishing characteristics
• Foraminifera…Forams
• Ameba-like body within a shell-like test
• Often build-up accumulates after many years
Phylum…example…distinguishing characteristics
• Ciliophora … paramecium
• All are ciliated• Macro & micronuclei• Oral groove & gullet
bring food into vacuole
• Contractile vacuole pumps out water
Phylum…example…distinguishing characteristics
• Sporozoa…Plasmodium
• Causes Malaria• Carried by female
Anopheles mosquito• During bite: insect
saliva inserted or infected blood ingested by insect
Phylum…example…distinguishing characteristics
• Euglenophyta…Euglena
• Animal-like flagella, eyespot, and reservoir (to ingest)
• Plant-like chloroplasts for photosynthesis
Phylum…example…distinguishing characteristics
• Bacillariophyta…Diatoms
• Unicellular marine algae; main producer in the sea
• Glass-like cell walls of silica
• Unique shapes
Phylum…example…distinguishing characteristics
• Dinoflagellata…dinoflagellates
• Unicellular algae; 2nd only to diatoms as main producer
• Often has flagella, plates, spikes, and other projections
• Causes “red tide”
Phylum…example…distinguishing characteristics
• Rhodophyta…red algae
• Small, multicellular algae
• May be an epiphyte on larger algae
• Used to make agar
Phylum…example…distinguishing characteristics
• Phaeophyta…brown algae
• Largest, multicellular algae
• Includes Kelp, which may grow 100 ft
• Plant-like body with holdfasts, stalks and blades, & air bladders for support
Sargasso Sea
Sargassum
Many square kilometers of the open Atlantic Ocean between the islands of the Azores and the Bahamas are covered by huge, floating algae called Sargassum. Known as the Sargasso Sea, this area of warm water is named for the brown algae that dominate its surface.
Phylum…example…distinguishing characteristics
• Chlorophyta…green algae
• Ancestors of plants
• In all environments, even on land
• Unicellular to multicellular (sea lettuce)
• Ex: Volvox and Spirogyra
Phylum…example…distinguishing characteristics
• Myxomycota… plasmodial slime mold
• A mass of cytoplasm containing many nuclei
• Uses spores to survive harsh conditions