Viruses and Bacteria TAKS Objective 3 (4C &4D)

Viruses Not living Noncellular 2 cycles –Lytic and Lysogenic Cannot grow or replicate on their own –Can only reproduce inside of a living host cell

Lytic Cycle Viral replication that causes the host cell to burst 5 steps –Adsoprtion, Injection, Replication, Assembly, & Lysis

Lysogenic Cycle Viral replication in which the virus stays inactive inside of the host cell without immediately causing the cell to burst. Steps include: –Adsorption, Injection, Recombination, Cell reproduction, Activation, Replication, Assembly, and Lysis

Viral Control Vaccines –Introduce a weakened pathogen to form antibodies or immunity against the pathogen Antiviral drugs –Interfere with viral DNA synthesis

Diseases Caused by Viruses HIV West Nile Chicken Pox Warts Ebola Influenza (flu), H1N1 (swine flu) Measles, Mumps, Rubella Polio

Is bacteria ALWAYS harmful?

The GOOD… Bacteria help us make milk, cheese and yogurt! Bacteria aid animals in digestion! Bacteria like penicillin are antibiotics. –Antibiotics can kill other harmful microorganisms.

The BAD… Can cause infections such as “strep” throat and “staph” infections. Can cause food poisoning and scarlet fever!

And The UGLY! Escherichia coli (E. coli) is commonly found in the intestines of humans and animals Most are harmless, but some can cause severe diarrhea that can even lead to death Can be transmitted by: –Eating undercooked beef or contaminated greens, swimming in contaminated water, fecal - oral transmission due to unhygienic practices

Kingdoms Archaebacteria and Eubacteria Archaebacteria - Found in harsh environments (volcanic vents) Eubacteria - true bacteria, most bacteria are found in this kingdom Most numerous organisms on earth Have a cell wall Prokaryotes –No nucleus nor membrane-bound organelles

Diseases Caused by Bacteria Bubonic Plague Cholera Diptheriia Lyme Disease Strep Throat Tooth cavities Tuberculosis