Virus and Bacteria Outline

1. Virus and Bacteria Outline • Virus A. microscopic,disease B. Non-living because C. Host cell D. Structure (3 parts) E. Lytic vs. lysogenic F. Examples G. vaccine • Bacteria A. Archae vs. Eu B. Structure C. Reproduction binary fission vs. Conjugation D. Bad, examples E. Good, antibiotic

2. Viruses and Bacteria Notes: Chapter 18

3. Viruses: • Microscopic particles that invade cells and cause disease • Non-living because they do not grow or develop or carry out respiration; they can only reproduce inside living cells (called a host cell)

4. Structure of a virus: draw and label • Nucleic acid core: either DNA or RNA • Capsid: outer protein coat • Tail fibers: used to attach to host cell

5. Viruses replicate in lytic or lysogenic cycles: (make a copy) • Lytic cycle (active): • Virus attaches to host cell • Injects viral nucleic acid which destroys host’s DNA • New viruses made inside the cell • Host cell pops, releasing virus to infect other cells

6. Lytic Cycle:

7. Lysogenic Cycle: • Viral DNA is joined with the host cell’s DNA (chromosomes) and can be passed on to daughter cells • Virus is present but not active • Explains why some diseases seem to go away only to reappear later and why some diseases don’t show up for many years

8. Lytic and Lysogenic Cycle:

9. HIV, flu, chicken pox, colds, hepatitis, measles Can you guess which diseases are caused by lysogenic cycles and lytic cycles? Examples of Viruses: HIV

10. Vaccinations: • Use weakened form of a virus to create antibodies against the virus

11. 2 minute review with partner • What are the 3 parts of a virus? 2. Describe the difference between the lytic and lysogenic cycles.

12. Archaebacteria: Prokaryotes Hetero/autotrophic Live in extreme environments Have DNA sequences similar to eukaryotes and are thought to be their ancestors Eubacteria: Prokaryotes Hetero/autotrophic Live everywhere Bacteria:(formerly Kingdom Monera)

13. Structure of a Bacterial Cell: • Strong cell wall; prevents bursting • DNA in single circular chromosome (no nucleus) • Plasmid: small ring of DNA DNA

14. Shapes of Bacteria: add to notes • Cocci: round shaped • Bacilli: rod shaped • Spirilla: spiral shaped

15. Bacteria replicate (reproduce) by: • Binary Fission: Bacteria reproduce by dividing in half (asexual) • Conjugation: hollow bridge forms b/t cells and genes exchanged (sexual- called “promiscuity”)

16. The importance of bacteria: (bad) • Cause disease (pathogens) • Ex: strep throat, tetanus, Lyme disease, tooth decay, salmonella, tuberculosis • Fewer deaths from bacterial infections because of sanitation and hygiene (sterilization/pasteuri-zation by heat, disinfectants) Lyme disease

17. The importance of bacteria: (good) • Recycle nutrients through decomposition • Nitrogen fixation: convert nitrogen into a form plants can use • Foods: cheese, yogurt • Medicines: produce antibiotics to kill bacteria by blocking growth /reproduction; insulin

18. 2 minute review with a partner • How do bacteria reproduce? • Each give one good thing about bacteria. • Each give something bad caused by bacteria.