Tuesday 4/26/16 Learning Target: Know the characteristics, reproduction and how to control viruses. Learning Outcome: Create a virus of your choice which illustrates its characteristics, reproduction and how to control it.

Is a virus a living organism? Viruses do not Grow Have homeostasis Metabolize Viruses do – Infect cells and use the cell to make more viruses -- Cause disease in many organisms

Viruses are particles of nucleic acid, protein, and lipids that invade living cells and reproduce. They are composed of a core of DNA or RNA surrounded by a protein coat called a capsid. Examples of Viruses: Influenza, colds, chicken pox, measles, polio, and AIDS.

1. Shape – they come in a variety of shapes. (see next slide) 2. Size 20-400 nanometers. 1 nanometer = 1 billionth of a meter. 3. Specificity = certain viruses only infect certain organisms…your dog can’t get chickenpox!

Retroviruses: Contain RNA as their genetic information Retroviruses: Contain RNA as their genetic information. It is then copied to DNA. This is “backwards” or “retro”. Viruses are considered parasites because they must infect a living cell in order to grow and reproduce. AIDS is this type.

1. Lytic Infection – a virus enters a cell, makes copies of itself and causes the cell to burst Attaches, entry, replication (make viral parts), assembly, and release http://www.npr.org/templates/story/story.php?storyId=114075029

Lysogenic Infection – a virus integrates its DNA into the DNA of the host cell. It may remain inactive for a period of time. The viral DNA is called a prophage.

1. Vaccine – a weakened dose of the virus 1. Vaccine – a weakened dose of the virus. When injected it usually prompts the body to produce an immune reaction to prevent illness.

2. Interferon – proteins that prevent virus from attaching to your cells and reproducing.

3. Antibodies – immune system proteins that attack and kill bacteria and viruses.