Biology I Chapter 25 Protists

Do Now What organelle contains the cell’s DNA and is the control center of the cell? Nucleus

Characteristics Introduction to Protists Protist-Single-celled or simple multicellular eukaryotes that don’t fit in any other kingdom. Emerged 2 billion years ago The oldest eukaryotic cells were protists

Unicellular or Multicellular Most are unicellular Some are colonial and form colonies in which several cells are joined into a larger body.

Autotrophs Heterotrophs Both Nutrition Autotrophs Heterotrophs Both

Motility Flagella-long, whip-like tail Cilia-shorter hairs, often in rows Pseudopodia-”false feet”

Asexual Reproduction Binary fission-a single Protist cell divides into two cells. Multiple fission-a form of cell division that produces more than two offspring.

Sexual Reproduction Conjugation-The process in which two Protists come together after meiosis to exchange parts of their genetic material

Do Now What is an organism that feeds on another organism, usually without killing it? Parasite What is the organism on which a parasite lives? Host

Do Now Explain the two main difference between prokaryotes and protists.

Phylum Protozoa Pseudopodia-large, rounded cytoplasmic extensions that function both in movement and feeding Amoeboid movement-a form of the internal flowing of a cell’s cytoplasm Amoeba Eats Amoeba Moves Death

Some sarcodines have protective shells called tests. Phylum Protozoa Some sarcodines have protective shells called tests.

Phylum Ciliophora Cilia vs. Flagella Contractile vacuole-squeezes the water out of the cell. Contractile Vacuole Macronucleus-contains multiple copies of DNA Micronucleus-participates in the exchange of genetic material during conjugation.

Phylum Sarcomastigophora African Sleeping Sickness Trypanosoma Carried by the Tsetse fly Cause sleeping sickness-fever, lethargy, mental deterioration, and coma.

Phylum Apicomplexa Adult forms have no means of locomotion. All are animal parasites Have killed more people than any other group of pathogens on Earth.

Phylum Apicomplexa Malaria Carried by mosquitoes Symptoms: headache and fatigue follow a cycle include severe chills and fever. The protist that causes malaria reproduces in the red blood cells of a human.

Phylum Apicomplexa Leishmaniasis Carried by the sand fly Causes boils Infects the liver, spleen, bone marrow, and causes death. Curse of the Lost City of the Monkey Gold

Algae Autotrophic protists. Lack specialized tissues Although algae are relatively unspecialized, they may have structures specialized for Anchoring to the ocean bottom. Reproduction. Movement.

Phylum Chlorophyta (Green Algae) Green algae and plants Have photosynthetic pigments Use starch to store food. Have cell walls made of cellulose.

Phylum Phaeophyta (Brown Algae) Include seaweeds and kelps Used as food Sargassum

Phylum Rhodophyta (Red Algae) Live at depths where algae lacking red pigments cannot survive Used as a thickening agent in ice cream, pudding, and icing. (carrageenan)

Phylum Bacillariophyta (Diatoms) Important producers in food webs Most essential to the production of photosynthetic products and oxygen for Earth’s heterotrophs Diatomaceous earth can be used to produce detergents, paint removers, and toothpaste.

Phylum Dinoflagellata (Dinoflagellates) Bioluminescence-the production of light by means of a chemical reaction in an organism Red Tide-when populations of dinoflagellates boom and cause the water to turn brownish red

Glowing water Waves

Phylum Chrysophyata (Golden Algae) Played a role in the formation of petroleum deposits

Phylum Euglenophyta (Euglenoids) Autotrophic and Heterotrophic Euglena

Do Now How do we classify animal-like protists? How do we classify plant-like protists?

Phylum Myxomycota (Plasmodial Slime Mold) Mass of cytoplasm that can ooze around obstacles Found on the floor of a forest The feeding stage of a plasmodial slime mold can be described as multinucleate. Slime Mold

Phylum Dictyostelida (Cellular Slime Mold) A pseudoplasmodium is a feeding-stage structure. Take up food from their environment by the process of phagocytosis. Both types of slime molds produce haploid spores in a fruiting body when they reproduce. Life Cycle

Phyla Oomycota and Chytridomycota (Water Molds) Most are free-living and aquatic, but some are parasitic.

Protists in the Enviornment Environmental roles of protists Produce large amounts of atmospheric oxygen. Photosynthetic protists are at the base of many food webs. Form important symbiotic relationships with other organisms.

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