1. Eukaryotes ………let’s get organized Page 114, 380-85, 390-94

2. Protists and Multicellular Last class we looked a little at archea and prokaryotes (bacteria) cells. Both the protists and all multicellular organisms are made up of Eukaryotic cells. Most multicellular organisms form symbiotic relationships with prokaryotes The adult human body is composed of tens of trillions of eukaryotic cells, but house hundreds of trillions of bacterial cells. (your “flora”)

3. Characteristics of Eukaryotes Membrane bound organelles Defined nucleus housing the DNA Larger than prokaryotes DNA is organized into chromosomes, long strands of DNA usually tightly wrapped around protein molecules. The DNA is in doubled coiled linear strands, not looped into plasmids like in prokaryotes.

4. The Organelles Just as your body contains several specialized organs to carry out needed functions, each Eukaryotic cell has membrane bound organelles which carry out specific functions in the cell You will need to memorize each organelle, it’s function and be able to label it

5. Organelles In all eukaryote cells: – Nucleus – Ribosomes – Mitochondria – Lysosome – Golgi apparatus – Plasma membrane – Cytoskeleton – Endoplasmic Reticulum – Vacuoles/vessicles In autotrophs (plant cells and algae) – Chloroplasts – Cell wall (in plant cells the vacuoles are usually larger and are used to hold and alter the shape of the cell using “turgor pressure”)

6. Cellular Power The chloroplasts in photosynthetic cells produce sugars from light, while the mitochondria in all cells respires these sugars to release energy from them. The DNA in the nucleus of Eukaryotic cells do not code for the building of chloroplasts or mitochondrion, instead they house their own DNA and replicate on their own within the cell.

7. Interesting Power Houses The DNA in the chloroplasts and mitochondrion are not linear, but looped, and are not in a nucleus, but free within the structure. They contain only membranes and ribosomes (few organelles) to perform their activities – Does this sound familiar?

8. Single celled eukaryotes (Protists) Autotrophs use energy (usually sunlight) to make sugar from a carbon source (usually CO 2 ) and water. Eukaryotic autotrophs are called algae. As they are photosynthetic their names often end with the suffix “phyta” Many protists are both photosynthetic and absorb food particles, or have varieties that do both Algae along with photosynthetic bacteria produce about 70-80% of the Earth’s Oxygen and are the primary food source for most aquatic life. (Plankton is a mixture of protists, bacteria and small organisms)

9. Each level in a food pyramid is called a “troph”, autotrophs, then, make there own food from an energy source (sunlight) Troph

10. Some interesting autotrophs Autotrophic protists are named with the suffix “phyta” meaning “photosynthetic” They all contain pigment (most commonly “chlorophyll”) which absorbs light energy and uses it to combine carbon based material into simple sugars Most autotrophic protists are marine dwelling and in the group called algae Algae produces the bulk 80% of the free oxygen in the atmosphere.

11. Types of Algae Algae are single celled, but may grow in colonies Some interesting algae include: – Euglena’s / Euglenophyta – Diatoms – Slime molds and seaweed (not really molds or weeds) (blue-green algae which aren’t really protists)

12. Euglenophyta – Euglena’s / Euglenophyta (the missing link?) Most Euglena’s have photosynthetic chloroplasts like plants or plant-like protists. But they lack a rigid cell wall, have a photosensitive spot, a flagellum for motion, and they ingest food particles in the dark like animals, or animal-like protists. Euglena’s are small, and when conditions are unfavorable (too hot) they grow a thick wall (cyst) around themselves and go dormant (like many bacteria)

13. Diatoms Diatoms are unique because they have cell walls made, not of carbon based starches or cellulose fibers, but of silicon based crystal filaments (similar to glass). When they die there cell walls rarely decompose and thus form diatomaceous earth, packed forms include limestone. The inner organic material decomposes anaerobically and forms most of the earth’s fossil fuels. (not dinosaurs) Look like microscope gemstones or kelidoscopes

14. diatoms

15. Algae colonies Algae can grow in colonies where the cells group together. These form and multicellular algae often miss- named slime mold and seaweed These include: Chlorophyta (green algae) Phaeophyta (brown algae/kelp), Rhodophyta (red algae) and Chrysophyta (golden brown algea), cell walls are made of a mixture of cellulose and silicate fibers)

16. Slime “molds” and sea “weed” Slime moldsSeaweed / kelp

17. The start of specialization These algae grow in colonies, as do some forms of bacteria, but the algae begin to show specialization. Some of them group into long filaments called “holdfasts” which secure the base of the colony to the ground or rocks underwater. Another group form the stem-like structure called the “stipe”, while still others form the “blade” of the algae which collects most of the light and does the bulk of the photosynthesizing. Kelp can be hundreds of feet long Not considered a multi-cellular organism, just a specialized colony of individual cells

18. Specialized Algae

19. Algae -> Plants It is believed that some algae growing in tidal regions, where sometimes exposed out of the water, developed into modern multicellular plants.

20. Blue-green Algae…….not! The variety often referred to as blue-green algae are not really algae, but colonies of cyanobacteria (a type of bacteria that contains chlorophyll)

21. Protozoans…….animal like protists “zo” like “zoo” referring to animals Protozoans do not have rigid cellulose cell walls, or contain chloroplasts. They are heterotrophic meaning they must take in food particles, sometimes bacteria or smaller protists. They often move by means of whip like flagella, or many short hair like cilia Some, like amoebas, move by pushing out a small portion of itself called a pseudopod, (false foot) then filling itself into the pseudopod

22. Common protozoans and locomotion Flagellates; move by flagella, long hair like projections, usually 2 or more, that whip or spin. They’re actually extensions of the inner cytoskeloton – Euglenozoa……..yep remember euglena’s have characteristics of both plant and animal like protists. Some varieties do not even contain chloroplasts, so some books refer to them as euglenozoas.

23. Common protozoans con’t cilliates;…..move by cilia (smaller hair like projections – Paramecium Ameobazoa….move by changing shape (pseudopods) – Ameoba’s Euglenea’s are also capable of “inchworm” type pseudopodic motion

24. Protist movement Flagella and cilia http://www.youtube.com/watch?v=QGAm6hMysTA pseudopod http://www.youtube.com/watch?v=PsYpngBG394 Inchworm 1:16 https://www.youtube.com/watch?v=NwZvfzMB2bg

25. Assignment Try #1-10, end of chapter review page 398, (chapter 17)