What makes us sick?

1. What makes us sick? • Bacteria • Virus • Fungi • Parasites • Other

2. Today, we are going to talk about bacteria! • Bacteriology is the study of bacteria • Bacteria have the greatest percentageof thebiomass on Earth!

3. Characteristics of Bacteria • They are prokaryotic. • They are unicellular. • They have DNA and ribosomes. So, are they living? How do you know?

4. Bacterial Structure • Basic structure of bacteria: Cell membrane Ribosome Cell wall Peptidoglycan* Flagellum DNA Pili

5. spherical (cocci) rod-shaped (bacilli) spiral (spirilla) Bacterial Structure • Bacteria have three distinct shapes:

6. Bacteria, all bad? • Bacteria have a variety of important uses: • Help make interesting food • Decompose organic matter • Nitrogen fixation • Human health • Biotechnology

7. Bacteria • Less than 1% of bacteria cause disease in humans, animals, and plants. • Bacteria can cause a variety of diseases: • Food Poisoning – Scarlet Fever • Tuberculosis – Whooping Cough • Cholera – Bacterial Meningitis • Pneumonia • Ulcers – Leprosy • Strep Throat – Tetanus

8. How Do Pathogenic Bacteria Work? • Bacteria produce disease in one of two ways: • Using cells for food: The bacteria break down healthy cells for food, destroying tissues • Releasing toxins: The bacteria produce a toxin (poisonous protein) that is released into the bloodstream where it can travel throughout the body, disrupting normal activity and damaging tissues

9. Exit Ticket: What are the characteristics of bacteria? What kingdom do bacteria belong? Are they living? Why or why not? Describe 2 examples of how bacteria can be helpful? How do bad bacteria make you sick?

10. Viruses • Virology is the study of viruses • Viruses are “biological entities” containing either DNA or RNA that require another cell to survive. • Viruses have some, but not all, of the characteristics of life. *Soareviruses living or non-living?* • Viruses seem to exist only to make more viruses!

12. Nucleicacidcore (DNA or RNA) Capsid (Protein coat) Viral Structure • All viruses have the same basic structure:

14. How Do Viruses Work? • In order to replicate and make copies of itself, viruses need a host cell. Any living cell can become a host cell (human, animal, plant, and even bacterial cells!) • Without a host cell, virusescannot function (i.e.-are harmless!) • Although any cell can theoretically become a host cell, specific viruses willonlyinfect specific cells (EX: HIV will only infect human T cells, a part of your immune system)

15. Lytic Cycle

16. How Do Viruses Work? • Attach: The capsid of the virus binds to receptor proteins on the surface of a host cell, tricking the host cell into thinking it’s not a foreign invader. • Inject: The virus then injects its genetic material (DNA or RNA) into the host cell. • Assemble: The viral genes are expressed, turning the host cell into a virus-making factory. • Repeat: The host cell eventually bursts, releasing the hundreds of newly formed viruses to infect surrounding cells! VIDEO CLIP: How Viruses Work

17. Lysogenic Cycle

18. Viruses • Viruses can cause disease in humans, animals, plants, and even bacteria! • Viruses can cause a variety of diseases: • Common cold – Polio • Hepatitis A, B & C – Influenza • Herpes – Mumps • Mononucleosis – Measles • Warts – Viral Meningitis • Chickenpox – AIDS VIDEO CLIP: Viral Disease

19. How the Lytic and Lysogenic Cycles Work Together!!!

20. Exit Ticket • Are Viruses alive? Justify your answer. • What are viruses made of? • Explain the basic difference between the lytic and lysogenic cycle. • What are the steps of the lytic cycle? • Name 2 viral diseases.

21. Protection • There are a few big ways to protect yourself against pathogens (disease causing agents) • Antibiotics (drugs to kill bacteria) • Antivirals (drugs to treat viruses) • Vaccination (using your body’s own immune system to preemptively guard against attack)

22. Antibiotics • Antibiotics can only be used to treatbacterial infections! • Target specific structures on bacteria to kill them. • First made from a fungus (penicillin), now most are made artificially. • Unfortunately, antibiotic resistance (where the antibiotic doesn’t kill the target bacteria anymore) is becoming a major problem.

23. Antivirals • Antivirals can only be used to treat certain viral infections! • Does not “kill” or disarm the virus permanently; only shortens symptoms by 1-2 days. • Usually only prescribed to patients with lifethreateningsymptoms or those that have a greater chance of developingcomplications (because of their age or they have a high-risk medical condition). • Just like antibiotics, there is evidence of antiviral resistance too!

24. Vaccination • Vaccines can only be used to prevent infections (both viral and bacterial) from leading to disease. • “Trick” your immune system to make antibodies that destroy foreign “bodies” or particles (such as bacteria and viruses). Your body remembers how to make these antibodies when the real thing invades. • Made from a weakenedvirus, inactivatedvirus, or by using only part of the virus/bacteria itself. VIDEO CLIP: Vaccination

26. To Review.... • What are the differences between viruses and bacteria? • Are all bacteria harmful? Explain. • When you get a cold, should you take an antibiotic to help you get better? Why? • What’s the best and easiest thing to do to avoid getting sick?

27. http://www.youtube.com/watch?v=3xRttWuf3wQ

28. Bacteria Virus Both