1. Viruses Doesn’t belong to any kingdom -It’s not a plant or an animal.
-It’s not a fungi, protist, or bacteria.
WHAT IS A VIRUS?

2. A virus is an infectious agent made up of nucleic acid (DNA or RNA) wrapped in a protein coat called a capsid.
Viruses have no nucleus, no organelles, no cytoplasm or cell membrane—Non-cellular vs

3. Viruses have either DNA or RNA but NOT both.
Viruses are parasites—an organism that depends entirely upon another living organism (a host) for its existence in such a way that it harms that organism.
HIV Infected Cell
(This is the reason why HIV is so incurable.)
A flea is a parasite to a dog and is harmful to the dog.

4. Virus Living Cell RNA or DNA core (center), protein coat (capsid)
Cell membrane, cytoplasm, genetic material, organelles
Structure
Copies itself only inside host cell--REPLICATION
Asexual or Sexual
Reproduction
DNA and RNA
Genetic Material
DNA or RNA
Growth and Development NO
YES—Multicellular Organisms
Obtain and Use Energy NO
YES
Response to Environment
YES NO
Change over time NO
YES

5. Are viruses living? NO ONE
How many characteristics of life do viruses possess?
ONE
*Genetic Material
Are viruses living? NO

6. Human Diseases Caused by Viruses:
Warts
common cold
Influenza (flu)
Smallpox
Ebola
Herpes
AIDS
Chicken pox
Rabies
Viruses can be prevented with vaccines, but NOT treated with antibiotics.
(antibiotics treat bacteria)

7. List of Vaccine-Preventable Diseases Mumps Pertussis Pneumococcal
Anthrax
Cervical Cancer (Human Papillomavirus)
Diphtheria
Hepatitis A
Hepatitis B
Haemophilus influenzae type b (Hib)
Human Papillomavirus (HPV)
Influenza (Flu)
Japanese encephalitis (JE)
Measles
Meningococcal
Mumps
Pertussis
Pneumococcal
Polio
Rabies
Rotavirus
Rubella
Shingles (Herpes Zoster)
Smallpox
Tetanus
Typhoid
Tuberculosis (TB)
Varicella (Chickenpox)
Yellow Fever

8. Certain viruses can only attack certain cell types
Certain viruses can only attack certain cell types. They are said to be specific.
Example: The rabies virus only attacks brain or nervous cells.
Surface Markers
Virus
Receptor Sites
It’s like the pieces of a puzzle. The ends have to match up so only certain pieces fit.
Cell

9. A virus recognizes cells it can infect by matching its surface marker with a receptor site on a cell.
Virus
Surface Markers
Cell
Receptor Sites

10. The Lytic Cycle
A virus CANNOT reproduce by itself—it must invade a host cell and take over the cell activities, eventually causing destruction of the cell and killing it. (The virus enters a cell, makes copies of itself and causes the cell to burst releasing more viruses.)
DNA/RNA is copied.
DNA/RNA injected into cell.
Virus attaches to cell.
Step 3
Step 2
Step 1
Virus copies itself.
Cell bursts (lyses) and releases new viruses.
Step 4
Step 5

11. Even 2,500 Years Ago, People Knew Immunity Worked.
Greek physicians noticed that people who survived smallpox never got it again.
The insight: Becoming infected by certain diseases gives immunity.

12. How does vaccination work?
A live or inactivated virus (Antigen) capable of producing an immune response in a person is given. This signals the production of antibodies to fight future virus attacks.

13. It works like this Patient exposed to pathogen
Carrying antigens A and B
Molecular Biology of the Cell Alberts et al

14. Bacteriophage—viruses that infect bacteria
Capsid (protein coat)
inside contains either
RNA or DNA
2. Flu (influenza), HIV
DNA or RNA
Surface Marker
Capsid (protein coat)

15. Amoeba sisters