1. VIRUSES

2. VIRUS A nonliving particle Are not cells Cannot:
reproduce on their own
make food
take in food
produce waste

3. Viral Reproduction Viruses must enter a living cell to reproduce
HOST – organism that provides a source of energy to a virus or another organism.
A virus acts like a PARASITE – organism that lives on or in a host and causes harm.

4. VIRUSES CONT. SIZES Smaller than bacteria
Measured in nanometers ( one billionth of a meter)

5. VIRUSES CONT.
BACTERIOPHAGE – robotlike shape, virus that infects bacteria, “bacteria eater”

6. VIRUSES CONT. STRUCTURES Two basic parts Protein coat for protection
Proteins on the surface determine which cells the virus can infect
Genetic material

7. VIRUSES CONT. HOW VIRUSES MULTIPLY Virus enters host
Takes over cell functions
Instructs cell to make new viruses
Cell burst, releasing viruses

8. VIRUSES CONT. Viruses cause diseases – Flu, Cold, HIV
Viruses are useful because they enter a host cell
Used as VECTORS - vehicle used to carry genetic material into a host or carry a disease
EX – Cystic Fibrosis

10. SECTION 2 BACTERIA Discovered by Leeuwenhoek
Looked at scrapings from his teeth and saw tiny, wormlike organisms.

11. Bacteria are PROKARYOTES – cells that do not have a nucleus.
Circular DNA
Some have a FLAGELLUM – whip-like structure used for moving.

12. CELL SHAPES
Most are either spherical, rodlike or spiral.

13. Some bacteria are AUTOTROPHS and some are HETEROTROPHS
Most need oxygen to perform respiration.
To some bacteria, oxygen is poisonous.

14. Reproduction
Binary Fission – one cell splits into two identical cells (asexual reproduction)
Sexual reproduction – two parents combine DNA
New combinations of DNA

15. If condition are good, bacteria will reproduce every 20 minutes
Population can increase rapidly

16. ROLE OF BACTERIA Add oxygen to atmosphere They produce food
Buttermilk, yogurt, sour cream and cheeses

17. - used to clean-up oil spills and gas spills. - help you digest food
- Bacteria are DECOMPOSERS – (organisms that breakdown dead organisms)
- used to clean-up oil spills and gas spills.
- help you digest food
- produce vitamins
- help prevent sickness.
- used to produce medicine (Insulin)

18. FUNGI Eukaryotes Cell walls Heteroptrophs (decomposers)
Uni- or multi-cellular
Mold, mushrooms, yeast

19. Fungi Cont.
Made of HYPHAE – branching, hollow tubes that make up the body of a fungus

20. Fungi Cont.
Obtain food by growing hyphae into food source and using chemicals to break down food so it can be absorbed
Reproduce sexually – ensure new DNA combinations
May lead to new adaptions
Reproduce by using SPORES – reproductive cell that can grow into an organism (asexual)
Can be very rapid reproduction

21. ROLE OF FUNGI
Decomposers – break down dead stuff, return nutrients to the soil.
Used to make food (yeast) and blue cheese. People eat mushrooms.
1928 Alexander Fleming – accidental discovery of penicillin (first antibiotic), came from mold
Cause disease in plants and animals (athletes foot)

22. Role of Fungi Cont.
Some help plants grow – absorb water and nutrients through the hyphae for the plant. The fungi gets food from the plant. (mutualism)
LICHEN – a fungus and either an algae or autotrophic bacteria that live in a mutualistic relationship.

23. LICHEN

24. PREVENTING DISEASES
Vaccines – substance put in the body that stimulate the body to produce chemicals to kill viruses.

25. TREATING DISEASES
Bacterial diseases – can be treated with ANTIBIOTICS – chemicals that kill bacteria
Some bacteria are becoming ANTIBIOTIC RESISTANT – able to survive in the presence of antibiotics
Common bacterial infections – lyme disease, Strep throat, food poisoning, Tetanus

26. VIRAL DISEASES Cannot be cured by medicine
You must build immunity viruses