MICROBES Bacteria and Viruses Bacteria Classification and Structure
MICROBES !!! Bacteria and Viruses
Bacteria: Classification and Structure
What are the 6 Kingdoms? • • • Archaebacteria Eubacteria Protists Fungi Plants Animals
Classification of Bacteria • Archaebacteria: extremists • Eubacteria: – Heterotrophs – Photosynthetic autotrophs – Chemosynthetic autotrophs
Archaebacteria • Live in extreme locations: – Oxygen-free environments – Concentrated salt-water – Hot, acidic water
Eubacteria - Heterotrophs • Found everywhere • Parasites: live off of other organisms • Saprobes: live off of dead organisms or waste (recyclers)
Eubacteria: Photosynthetic Autotrophs • Photosynthetic: make their own food from light • Cyanobacteria: blue-green, yellow, or red • ponds, streams, moist areas
Eubacteria: Chemosynthetic Autotrophs • Get energy by breaking down inorganic substances like sulfur and nitrogen • Make nitrogen in the air usable for plants {Very Important}
Structure of Bacteria • Two parts to Bacteria Structure: – Arrangement – Shape
Arrangement • Paired: diplo • Grape-like clusters: staphylo • Chains: strepto
Shape • Rod: bacillus • Spheres: coccus • Spirals: spirillum
Examples • Streptococcus: chains of spheres • Staphylospirillum: Grapelike clusters of spirals • Streptobacillus: Chains of rods
Bacterial Diseases • • • Pneumonia Strep Throat Meningitis Salmonella Cholera Bubonic Plague
Treatment • Bacterial infections can usually be treated by using antibiotics. – The first antibiotic was Penicillin which was discovered by Alexander Fleming in 1928. – Penicillin is derived from a fungus and works by eating holes in the cell wall of the bacterial cells
Viruses
Alive? • Viruses are non-living! – They do not carry out respiration. – They do not grow or develop – Cannot reproduce without a host cell
Viral Structure • Inner Core – Contains nucleic acid (DNA or RNA) with instructions for making copies of the virus • Outer protein coat called a capsid • May have an additional layer of protein called an envelope
Viral Structure • 4 major shapes of virus – – Helical Polyhedral Studded Envelope Polyhedral with leglike extensions
Viral Reproduction • Lytic Cycle (eg. The flu) – Very Fast (about 30 minutes) – Takes over host cell’s genetic material – Kills the host cell quickly • Lysogenic Cycle (HIV virus, herpes simplex 1) – Not fast – A provirus is formed-it becomes part of the host cell’s chromosome – Changes the host cell, doesn’t kill it quickly – Can enter the lytic cycle at any time, usually because of some sort of stress
Lytic Cycle
Lysogenic Cycle
Viral Diseases • • • Herpes Chicken Pox Influenza Meningitis Measles Mumps
Treatments for Viral Diseases • Vaccines- alert the immune system without causing the illness • Anti-viral drugs • Many have no cures but simply medicines to control symptoms
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