Viruses, Bacteria & Diseases

1. Viruses, Bacteria & Diseases

2. Viruses • Viruses are NOT cells. A virus is an infectious agent made up of: • a core of nucleic acid (RNA or DNA) • a protein coat (capsid) • Genetic material carries information for multiplication • Hijacks biochemical machinery of host • cell to carry these processes out • So…viruses are NOT LIVING

3. Characteristics of life

4. Re-Cap • Viruses are NOT ALIVE. Viruses do not: • Grow • Have homeostasis • Metabolize • Viruses do: • Infect cells and use the cell to make more viruses • Cause disease in many organisms

5. Envelope (part of the protein coat) Capsid (part of the protein coat) Nucleic acid (either DNA or RNA) Structureof a virus ENVELOPE NUCLEIC ACID CAPSID

6. A virus that contains RNA instead of DNA Human Immunodeficiency Virus (HIV) is a retrovirus HIV causes AIDS Retrovirus CAPSID ENVELOPE RNA

7. A virus that only infects bacteria Bacteriophage CAPSID HEAD DNA CAPSID TAIL FIBER

8. Ticking time bombs . . . Viruses do not reproduce by themselves. They invade a living cell and let the cell do the work for them.

9. Lytic Cycle The viral infection that rapidly kills the host cell is the lyticcycle.

10. Cycle Illustration 1 2 3 4 5

11. Lysogenic Cycle The viral infection that enters a cell, remains harmless for a period of time (sometimes years), and then becomes harmful later is called the lysogenic cycle.

12. Lysogenic Cycle In the lysogenic cycle, the virus reproduces by first injecting its genetic material, indicated by the red line, into the host cell's genetic instructions.

13. All viruses act like parasites, harming the host cell. Viruses cause disease in every kind of organism—animals, plants, fungi, protists, and bacteria. Role of viruses

14. HIV Measles Smallpox Influenza Chicken pox Common cold Herpes Warts Mononucleosis Mumps Some viral diseases

15. A retrovirus Infects human helper T-cells, which are associated with the immune system. Modes of transmission: Sexual contact with an infected person Sharing needles with an infected person Blood transfusions (rare) Breast feeding Etc. HIV

16. Human Papilloma Virus Causes warts Most common STD in the United States 80% of women by the age of 50 will have acquired some strain of genital HPV. HPV vaccine HPV

17. Symptoms: body aches, fever, coughing, runny nose, fatigue, usually lasting about a week. Mode of transmission Airborne (air droplets) People still die from influenza. Influenza (flu)

18. Viral diseases • usually cannot be cured, but many can be prevented by • Good hygiene • Immunization

19. Bacteria Bacteria are Prokaryotes. Prokaryotic Cells: • Have no nucleus • Do not have membrane bound organelles • Are very small • Often have a flagellum for movement

20. Bacteria are classified according to their shape: Round is called cocci Rod shaped is called bacilla Spiral shaped is called spirilla Shapes of bacteria

21. Bacteria are found in all environments Where do they live?

22. Some bacteria are helpful E. coli Yeast V.streptococci Lactobacillus Some bacteria are harmful E. coli S. pyogenes S. aureus Y. pestis Role of bacteria

23. Causes strep throat, pneumonia, and other infections. Named based on the shape and orientation of the bacteria. Streptococcus

24. Cause of staph infections that occur on the skin or in wounds. (ex. MRSA) But, Certain types of staph reside normally on the skin. Staphylococcus

25. Swelling of the upper respiratory tract DPT Vaccine Can also infect skin cells. Diphtheria

26. How do bacteria cause disease? The release toxins that interfere with normal activity.

27. Vaccines to prevent. Antibiotics to cure (pennicillin, amoxycillin, etc). Prevention/Cure