VIRUSES

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

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.

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

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

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

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

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

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

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

CELL SHAPES Most are either spherical, rodlike or spiral.

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

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

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

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

- 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)

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

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

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

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)

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.

LICHEN

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

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

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