1. Viruses

2. A virus is a small infectious agent that can replicate only inside the living cells of organisms. Latin for “poison” (Don’t draw line there’s more!)

3. Viruses vs. Cellular Life Viruses DNA or RNA Need a host to replicate Never contain organelles Do not convert energy Cellular Life Only DNA Can reproduce independently Eukaryotes contain organelles Convert energy to perform tasks

4. Viruses are not cells and are not made up of cells It contains genetic material and protein that can invade living cells THEY ARE NOT ALIVE! They don’t Contain a nucleus or cytoplasm Eat Grow Carry out respiration Or other biological functions

5. The Structure of a Virus A virus is surrounded by a capsid (protein coat) which determines the shape of the virus The capsid contains nucleic acids (DNA or RNA) They also contain tail fibers which they utilize for attachment Spike fibers at the base of the virus are used to pierce the cell

6. Classification Viruses are classified by Shape Size Host type Type of genetic material (DNA or RNA)

7. Viral Replication Viruses replicate in one of two ways: Lytic – begins immediately Lysogenic – DOES NOT begin immediately

9. Viral Reproduction – Lytic Cycle Lytic Cycle – Attaches to host – Injects genetic material into host – Cellular machinery duplicates genetic material and creates viral proteins (capsids, tail fibers) – New viruses are assembled – New viruses exit the cell by bursting the cellular membrane End result – more viruses made, cell dies

10. Lytic Cycle Release Attachment Assembly Replication Entry

11. Lysogenic Cycle – Attaches to host – Injects genetic material into host – Viral genetic material is inserted into host genome – Viral genetic material lies dormant – When cell reproduces, new copies have viral genetic information End result – more viral genome made, cell lives

12. Lysogenic Cycle Attachment Entry Separation Insertion Reproduction

13. DiseaseTransmissionSymptoms AIDS/HIVSexual contact; contaminated blood or needles Immune system failure; fatal Common Cold Inhalation, direct contact Sinus congestion, muscle aches, cough, fever SmallpoxInhalationBlisters, lesions, fever, blindness, scars; often fatal Influenza (Flu) InhalationHeadache, muscle ache, sore throat, cough, fatigue, fever, chills WartsDirect contactLumps on skin or mucus membranes HerpesDirect contactOpen sores on mucus membranes Common Viral Diseases

14. Most viruses have NO cure Influenza, & HIV but some viruses like Small- pox have vaccines. Vaccines contain a weakened or killed virus that provides immunity to the disease.

15. How are viruses transmitted? Airborne Contaminated food or water Vectors/Infected animals Sexual contact Contaminated blood

16. Bacteria Notes

17. Bacteria Are Everywhere! Bacteria are the smallest organisms on the planet Oldest organisms on the planet, ~3.5 billion years old Some are beneficial, some cause disease

18. Structure of Bacteria Bacteria are prokaryotic (NO nucleus) Basic structure includes: Cell wall Cell membrane Cytoplasm DNA is found in the cytoplasm Some bacteria may have a circular piece of DNA called a plasmid

19. Identifying and Naming Bacteria Three basic shapes: Round = cocci Rod = bacilli Spiral = spirilla Various arrangements Individual cells, pairs, chains, or clumps Strepto- means more than 2 in a straight line Staphylo- means cluster Diplo- means two

20. Bacteria Reproduction Binary Fission Bacteria reproduce by splitting in half. DNA is copied while cell continues to grow When it’s large enough, it pinches off two equal-size cells Conjugation * Note: bacteria do NOT make love

21. Bacteria can be GOOD! About 99% of bacteria are good Provide oxygen for atmosphere (photosynthesis) Decompose dead matter Fix nitrogen in soil for plants (nitrogen fixation) and return nitrogen to atmosphere (dentrification) Help clean up oil spills Probiotics in yogurt help our digestive and immune system

22. Bacteria can be BAD! Less than 1% of bacteria are harmful These bacteria can cause diseases such as tetanus, syphilis and toxic shock syndrome

23. Antibiotics help slow bacteria growth or kill it. Prevents cell wall from forming Also kills the good bacteria  Antibiotic Resistance : bacteria become resistant to antibiotics and pass traits on to offspring EX: Antibiotic Resistant Gonorrhea