1. Viruses and Bacteria Unit 5 – Lesson 2 Which is alive? What do they do? VIRUS BACTERIA

2. VIRUSES

3. What is a Virus?  For something to be living look for three main characteristics: DNA reproduce obtain and use energy  Is a virus living? NO!

4. What is a Virus?  A virus has DNA. It is surrounded by a protein coat.

5. What is a Virus?  Viruses can reproduce. They make copies of themselves only inside a living host cell.

6. Viruses  Achoo!  Be careful! Sometimes sneezing and spreading your germs can spread viral infection.

7. Viral Reproduction 1. The virus attaches to a specific host cell.

8. Viral Reproduction 2. The virus’ DNA enters the host cell.

9. Viral Reproduction 3. The DNA of the virus causes the cell to make copies of itself!

10. Viral Reproduction 4. New viruses form inside the host cell.

11. Viral Reproduction 5. New viruses are released as the host cell bursts open and is destroyed.

12. Virus Multiplication Active viruses – make the host cell create new viruses, which kills the host cell. Latent viruses – hide in the host cell without destroying it.  Virus hereditary material becomes part of the host cell hereditary material.  Latent viruses can become active and then destroy the host cells. I’ll hide out! They’ll never find me!

13. Effects on Organisms  Most viruses infect only specific kinds of cells.  Viruses are often carried to the host through the air.  The virus and host cell must fit together exactly to begin a viral infection.

14. Fighting Viruses  Vaccines – weakened virus particles that allow the host to fight some diseases.  Treating viral diseases Public health measures can prevent or slow disease. What they tell you a shot is like… What a shot is really like…

15. BACTERIA

16. Bacteria  Bacteria has DNA, reproduces, and obtains and uses energy. Bacteria is living. Want proof that bacteria reproduces? Smell your feet before you put on shoes, then smell them again at the end of the day when you take your shoes off.

17. Bacteria  There are six kingdoms of life, two of these kingdoms are bacteria. Archaebacteria Eubacteria

19. Bacteria  Bacteria are prokaryotes. No organelles Free floating DNA  They reproduce by a method called fission.

20. Bacteria  Bacteria can be both beneficial and harmful.  Bacteria can be found and used ANYWHERE You have more bacteria in/on your body than you have BODY cells. Are you human or bacteria?

21. Beneficial Bacteria  Examples of beneficial bacteria Decomposition The Human Body – Intestines Food (yogurt – probiotics) Nitrogen Fixation  turns nitrogen gas into a compound organisms can use bacteria help decompose landfills bacteria in foods help with intestinal health

23. Harmful Bacteria  Pathogenic bacteria are types of bacteria that carry disease or cause harm to humans. E. Coli Streptococcus

24. Bacteria  Harmful bacteria can be treated by antibiotics.  Frequent use of antibiotics may cause some bacteria to develop a resistance. beneficial harmful mutated harmful