1. Viruses

2. What is a virus? Virus: small, nonliving particle that invades and then reproduces inside a living cell Considered nonliving because viruses are not cells. They don’t use energy to grow or respond to their surroundings Only multiply when within a cell.

3. Host: living thing that provides a source of energy for a virus Parasite: organisms that live on or in a host and cause harm Viruses can infect organisms in all 6 kingdoms Viruses are named after the disease it causes or the organism they infect

4. The Shapes and Sizes Can be in all shapes and sizes Round, rod-shaped, bricklike, threadlike, bulletlike, robotlike Bacteriophage: virus that infects bacteria Vary in shape –Smaller than cells and cannot be seen with our microscopes –Smaller than bacteria cells

6. Structure of Viruses All viruses have two parts –Outer coat that protects –Inner coat made of genetic material Genetic material contains instructions for making new viruses Outer coat plays important role during invasion of a host cell

7. How viruses multiply After attaching it enters the cell –T–Takes over the cell’s functions –D–Directs to make more viruses Active viruses: immediately goes to action –M–Makes copy after copy Hidden viruses: becomes part of the cell and waits to become active

8. Influenza, commonly called "the flu," is an illness caused by viruses that infect the respiratory tract. Symptoms: fever 100° F to 103° F in adults higher in children respiratory symptoms such as, cough, sore throat, runny or stuffy nose, headache, muscle aches, and extreme fatigue. Viral Infections

9. Rabies Viral Infections People usually get rabies from the bite of a rabid animal. Rabies can be confirmed only in a laboratory.

10. Varicella common name “Chicken Pox” rash on the skin. occurs mostly in winter and spring, but can happen any time of the year. Very contagious 90% of all people in the world will experience chicken pox at some time during their lives, unless they receive the vaccine.

11. Polio Polio is a disease that is able to damage the nervous system and cause paralysis. The poliovirus enters the body through the mouth. Non-paralytic polio will result in fever, vomiting, abdominal pain, lethargy, and irritability. Some muscle spasms in the neck and back, with muscles generally tender to the touch. Polio was declared eradicated in the U.S. in 1979

12. It is transmitted mainly by infected saliva. This typically causes enlargement of one or more of the salivary glands. These glands are located on either side of the face, below the ears. The main symptoms are severe swelling and soreness of the cheeks and jaw. Mumps Measles Symptoms: fever, listlessness, loss of appetite, mild head cold, sore throat, dry cough, and tender lymph gland enlargement in the neck area. Measles rash is a reddish, slightly raised that first appears on the face and neck areas.

13. Process of injecting a person with a dead or weakened virus which stimulates the immune system to build cells that destroy the invader cell upon next entry DPT: Diphtheria, Pertussis (Whooping cough) & Tetanus Rubeola (Measles) MMR: Combined Measles, Mumps and Rubella Polio Pneumococcal pneumonia Hemophilus meningitis Hepatitis B Rotavirus

14. Caused by a virus Influenza-flu Rabies Chicken pox Polio Measle and mumps Thank goodness for vaccines!!

15. Review Explain why biologists consider viruses to be nonliving. What is the basic structure of a virus? Compare the two ways viruses can multiply.