Virus
So what do we already know about VIRUSES?
V: Introduction to Viruses
What is a “Pathogen”? Definition: a disease causing agent.
What is a “Virus”? Definition: a pathogen, or disease causing agent, not considered living because it cannot reproduce on its own.
Virus Reproduction A virus must have a HOST CELL to reproduce.
Structure of a “Virus” Capsid: outer protein coat. Genetic Material: DNA or RNA.
V: Invasion of the Virus
“Lytic Cycle” Definition: process in which a virus enters a cell, makes a copy of itself, and causes the cell to burst.
“Lytic Cycle” (Viral Reproduction)
“Stage A (1)” The virus lands on the host cell and then injects its genetic material into the host cell.
“Stage B (2)” The virus using the host cell to synthesize, or make, viral proteins (capsids) and nucleic acids (genetic material-DNA or RNA).
“Stage C (3)” The virus assembles (puts together) capsids and nucleic acids to prepare for release.
“Stage D (4)” The host cell breaks open (lysing) and the newly assembled viruses begin to be released.
V: Bacteriophage Lytic Cycle
“Lysogenic Cycle” Definition: process by which a virus embeds its DNA into the DNA of the host cell and is replicated along with the host cell's DNA. Lysogenic cycle is a viral reproduction cycle in which the virus is dormant until it enters the lytic cycle.
“Lysogenic Cycle”
What is a “Retrovirus”? Definition: a virus that contains RNA as its genetic material instead of DNA.
Viruses cause “Disease” How: by disrupting the body’s normal equilibrium. In many viral infections, viruses attach and destroy certain cells in the body, causing the symptoms of the disease.
(Human Immunodeficiency Virus) “HIV” (Human Immunodeficiency Virus) Definition: retrovirus that destroys white blood cells called helper T cells and causes the disease known as AIDS (Acquired Immune Deficiency Syndrome).
“Influenza” (Flu or Grippe) Definition: a highly infectious respiratory disease. Your best defense against this virus is to receive an annual vaccination (according to the Mayo Clinic).
What is a “Vaccine”? Definition: a preparation of weakened or killed pathogens. When injected into the body, a vaccine sometimes prompts the body to produce immunity to the disease.
V: How Vaccines Work
What is “Immunity”? Definition: the body's ability to destroy new pathogens.
What are “Antibiotics”? Definition: compounds that block the growth and reproduction of bacteria. DO NOT work on viral infections!
Who is a “Immunologist”? Definition: a person who specializes in the immune system, to study the mechanism used by the virus to infect cells. If a company wants to develop antiviral drugs, they would need to ask a research immunologist.