viruses, bacteria, protists, fungi

1. Science Notes: Ch. 9; Viruses, Bacteria,
Protists, & Fungi

2. Main Topics...
Structure & Function
Life Cycles, & Reproduction
Levels of Organization (cell, tissue, etc)

3. Virus Structure...
Not considered living. Smaller than cells
Basically a bag made of organic protein
containing a core of viral DNA...

4. Virus Reproduction
Reproduce by parasitizing host DNA
Use host DNA to reproduce themselves
Bacteriophages are viruses that infect
bacteria.

6. Viruses are either...
Active... Reproducing themselves inside
another creature by taking over their
DNA and using it to make copy after
copy or...
Inactive... “hiding” its DNA dormant
inside the host cells’ DNA waiting to
become active later.

7. Viral diseases...
Influenza (“The Flu”); fever, sore throat,
headache, cough, not usually treated with
medicine (Different from a “cold” which is
caused by bacteria).
Chicken pox; Fever, red itchy rash.
Treatment is with a vaccine. A vaccine is a
substance that triggers the bodies immune
response.

8. Bacteria; Structure...
Living prokaryotes, a single cell.
Cell membrane, cell wall, no nucleus,
DNA floats in cytoplasm. Ribosomes
and other organelles.
May have flagella.
Vary greatly in size to as big as a period.
Shape determined by chemistry of cell
wall.

9. Structure...

10. Bacteria Function
Getting food and energy...
Some bacteria are autotrophic;
photosynthetic & chemosynthetic
Some are heterotrophic; milk, meat,
detritus on the forest floor.
Most bacteria are aerobic; need oxygen
to get energy from glucose.
Some are anaerobic; don’t need oxygen

12. Bacteria reproduction
Asexual binary fission; one bacteria splits
into two by meiosis.
New bacteria identical to parent.
“Sexual” conjugation; not really sexual
reproduction... one bacteria transfers
genetic material to another across a thin
tube, thereby increasing diversity.
Then new bacteria reproduces by fission.

13. Bacteria reproduction...

14. Roles of Bacteria...
Autotrophic bacteria produce Oxygen!
Pasteurization (heat) kills most food but we
need bacteria to make; bread, cheese, cider
vinegar, buttermilk, yogurt, sour cream, etc.
Major decomposers!
Clean up oil spills
Help with digestion.

15. Protists... What are they?
Protists mimic animals, plants, and fungi
Diatoms; jewels of the sea
Foraminifera.
Brown, red, green algae (including seaweed)
Slime molds

16. Protist Characteristics...
Unicellular and multicellular
Some sessile, some mobile.
All Eukaryotic,
Some autotrophic, some heterotrophic.
Cannot be classified as animals, plants, or
fungi.
Most reproduce asexually

17. Plant-like protists...
Diatoms, dinoflagellates, Euglenoids, Algae
Algae vary greatly in size and structure
Pictures...

18. Diatoms... jewels of the sea...

19. Algae...

20. Animal-like protists (Protozoa)...
Amoeba, Paramecium, Foraminifera, Plasmodium
Protozoans are unicellular and heterotrophic
Four main functional groups...
The Sarcodine pseudopod group,(amoeba)
The Ciliates group (paramecium)
The Flagellates group (Foraminifera)
The Parasite group (plasmodium)

21. Foraminifera...

22. Fungus-like protists...
Heterotrophs, cell walls, use spores to
reproduce.
Able to move at some point in life.
Slime molds, water molds, downy mildews.

23. Slime molds...

24. The Fungi...

25. Fungi Characteristics...
Eukaryotes, cell walls, heterotrophs, spores to
reproduce.
Tiny yeasts to the largest organism on Earth,
one spreading over acres.
Cells arranged into hyphae; branching thread-
like tubes.
Three main groups; sac fungi, club fungi, and
zygote fungi.

26. Types of fun guy (tee hee)...
Club fungi (mushrooms, rusts, puffballs...
Sac fungi (yeasts, morels, truffles)...
Zygote fungi (fruit & bread molds)...

27. Fungi reproduction...
Most reproduce using spores in...
Reproductive structures called fruiting bodies
Asexual reproduction happens when there is enough food and
moisture.
Two methods; Spores &
Budding (mitosis); No spores are produced
Parent yeast cell goes through mitosis and a small yeast
cell grows.

28. Sexual reproduction in fungi...
Happens when growing conditions
unfavorable.
Hyphae of two fungi grow together and
genetic material is exchanged.

29. Role of fungi in nature
Foods made by humans
Decomposers in the environment
As disease fighters for humans
Disease-causing fungi
Some fungus essential for plant growth
Lichens; a fungus and either an algae or
bacteria.

30. The End.