The Origin of Eukaryotes 1. Internal membranes evolved from inward folds of the plasma membrane. 2. Endosymbiosis – chloroplasts and mitochondria evolved from prokaryotes that lived within a larger host prokaryotes.

Protists Eukaryotes that are not animals, plants or fungi.

Grouping Protists by Type of Nutrition Animal-like: heterotrophs (protozoans) – ingest food Fungus-like: heterotrophs – feed on decaying organic matter. Plant-like: autotrophs (algae) make their own food by photosynthesis

Protozoans Characterized by how they move Can be free living or parasites: Parasites live in a close relationship with a host, and causes it harm.

Protozoans with Flagella Called Zooflagellates Most reproduce asexually Some are free living, some are parasites

Protozoans with Pseudopodia Pseudopodia – temporary extensions of the cytoplasm also used to surround and engulf prey Examples: Amoeba Forams – has porous shell from which pseudopodia extend through

Protozoans with Cilia (cilialites) Example: Paramecium Arrangement of cilia are adapted to different functions. Many cilia joined together work to aid movement Cilia rings around the mouth aid in the uptake of food. Can produce sexually or asexually. Have two types of nuclei.

Protozoans Lacking Motility Paracites that don’t have a means of moving – Apicomplexans The apical complex is a structure on the tip of the cell that helps for penetrating host cells.

Describe two "animal-like" characteristics of protozoans. No cell wall Frequently are free living Eat organisims

Describe two functions of cilia in protozoans. Mobility Filter water for food particles

Fungus-like protists Slime Molds Plasmodial Cellular Water Molds Mildews

Plasmodial Slime Molds Unicellular Plasmodium – single mass of cytoplasm undivided by membranes & containing many nuclei Extend pseudopodia to engulf bacteria & organic matter. Cytoplasmic streaming to distribute nutrients and oxygen throughout the organism.

Plasmodial Slime Molds When food and water are scarce, sporangia develop. Tips of sporangia produced spores that can be dispersed by wind. In favorable conditions the spores release haploid cells that unite forming zygotes.

Cellular Slime Molds Have both unicellular and multicellular stages in the life cycle.

Plant-like Protists Photosynthetic

Euglenoids Single-celled Posses one or two flagella Lack a cell wall

Dinoflagellates Unicellular Cell wall made of cellulose 2 flagella which produce a spinning movement Component of plankton- microscopic organisms near the surface of bodies of water.

Dinoflagellates Impacts: Red tides Bioluminescence

Diatoms Unicellular Cell wall made of silica. When they die, they sink to the bottom of the ocean forming diatomaceous earth.

Seaweeds Multicellular Classified by the pigment they contain Brown Algae – accessory pigments & chlorophyll Red Algae – red pigment & chlorophyll Green Algae – chlorophyll

Test Questions RNA was believed to be the first nucleic acid because it can copy itself in small pieces without the aid of enzymes.

Cells vs. Viruses Cells Alive Reproduced independently Cell membrane surrounds nucleic acid Viruses Inert Need host to reproduce Protein coat with nucleic acid inside

Bacteria vs. Virus Bacteria – Reproduce independently Can be treated with an antibiotic Virus Need host to reproduce Can be prevented using a vaccine

Transformation – Bacteria pick up pieces of DNA from the environment Conjugation – two cells join and transfer genetic info between them Transduction – Viruses infect bacteria carrying genes from one cell to the next

Reproduction of a Virus