1 Latin for “poison” A virus is a particle that can only be seen with an electron microscope.

2 Day 1 Goal: The TAKS objective asks students to: compare the structures and functions of viruses to cells: 1.Compare & contrast structure of viruses and cells 2.Overview of virus structure 3.Function of viruses

3 Booooo, who cares about viruses? Doing the following activity will help you understand: –how quickly viruses spread –why it’s important to prevent the spreading of viruses –THEN….you’ll want to know more about the these tiny particles that can be so deadly!!!! Engage

4 Viruses spread! If you were a taxonomist, how would you classify these infectious particles? Predict the kingdom you believe they are assigned to.

5 Analyze the following virus. Using prior knowledge of the structure of a cell, compare and contrast cells to viruses. Explore.. ligands

6 A virus is a non-cellular particle made up of nucleic acid (genetic material) and protein that can invade living cells. Cannot reproduce without a host Capsid head filled with DNA or RNA Covered in a sticky glycoprotein coat for specific attachment to host cell site What is a Virus? Shapes of viruses Explain

7 Viruses are not cells and are not made- up of cells. They don’t… Contain a nucleus or cytoplasm Eat/ metabolize nutrients Grow and develop Carry on respiration Or perform other biological functions

8 A virus is surrounded by a capsid (protein coat) which determines the shape of the virus. Tail fibers for attachment to host cell. The capsid contains nucleic acids (either DNA or RNA).

9 Viruses are classified by:  type of host cell  presence of DNA or RNA (retroviruses)  shape:

10 Now, try to assemble a basic virus: online.com/objects/index_tj.asp?objID=MB Y101http:// online.com/objects/index_tj.asp?objID=MB Y101

11 Viruses differ from living cells in that all viruses — A metabolize nutrients B can be destroyed by antibiotics C have rigid cell walls D must be reproduced in living cells Remember, viruses can’t reproduce on their own. The need to use the machinery of a living cell to produce their DNA and proteins.

12 Day 2 Goal: Describe the role of viruses in causing diseases 1.Diseases viruses may cause (just a few, there are too many to cover and some still unknown) 2.How do viruses do this? 3.Treatment/ prevention

13 Can you think of some illnesses caused by viruses? Flu ( Influenza) Common cold AIDS hepatitis chicken pox measles mumps E. Bola Pneumonia West Nile cervical cancer Warts Polio Hepatitis Rabies Smallpox Viral Infections

14 Flu Attack! How A Virus Invades Your Body : NPR I still don’t get it! If a virus is not a living thing than how do they replicate?

15 Wait, I’m made up of millions and millions of cells. Does that mean ANY virus can infect ANY type of cell? How do viruses recognize a target cell? Activity

16 Using the following illustration, explain the process of VIRAL REPLICATION. 1. Virus recognizes and attaches to its host cell

17 Viruses can inject their DNA into a HOST cell, taking over its machinery, reproducing, and then killing the cell.

18 Virus injects its DNA Virus DNA commands host cell to make new viral parts New viral parts assembled Cell lyses (breaks apart) and new viruses are released Virus attaches to host cell. Another example of a virus reproducing

19 Ex of a virus, its host cell and the disease it causes: The HIV virus causes AIDS by attacking white blood cells called Helper T cells that prevent infections in the body. Think of a virus and the host cell it targets. Predict what would happen to this virus if it did not have the host cell to attach to nor invade.

20 VIRAL DISEASES 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

21 Should you ask for an antibiotic when you have the flu? Vaccines contain a weakened or killed virus that provides immunity to the disease. NO

22 1. Vaccines can prevent them. A weakened or dead strain of the virus is injected 2. Antibodies form in days and will give immunity from the virus. Can a disease be cured? Virus No! Bacteria Yes! 1.Antibiotics kill most bacteria 2.Antibiotic resistance occurs when some strong bacteria aren’t killed by antibiotics. They reproduce and are resistant. Natural Selection in action

23 1. Most viruses infect a specific kind of cell. Which of the following are infected by the human immunodeficiency virus (HIV)? A Helper T cells B Liver cells C skin cells D Red blood cells Remember, HIV infects helper-T cells (white blood cells, not red) causing the immune system to be unable to fight infection

24 2. Which of the following explains why antibiotics can treat flu-like symptoms caused by bacteria but are ineffective against flu? A Flu is a response to an antigen. B Antibiotics require time to work. C Antibiotics strengthen antibodies. D Flu is caused by a virus. Remember, the flu is caused by a virus. They can sometimes be prevented by vaccines, but cannot be cured with antibiotics.

25 Stations Activity Emerging Infectious Diseases