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Virus Notes

Virus Notes. Chapter 19 Section 19-2. Virus Characteristics. 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 .

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Virus Notes

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  1. Virus Notes Chapter 19 Section 19-2

  2. Virus Characteristics • 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.

  3. Ways viruses vary……. • 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!

  4. Examples

  5. Retroviruses • 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.

  6. Viral Reproduction #1 • 1. Lytic Infection – a virus enters a cell, makes copies of itself and causes the cell to burst • Attaches, entry, replication, assembly and release • http://www.npr.org/templates/story/story.php?storyId=114075029

  7. Viral Reproduction #2 • Lysogenic Infection – a virus integrates its DNA into the DNA of the host cell. It many remain inactive for a period of time. • The viral DNA is called a prophage.

  8. 3 Ways to control viruses: • 1. Vaccine – a weakened dose of the virus. When injected it usually prompts the body to produce an immune reaction to prevent illness.

  9. Ways to control viruses: • 2. Interferon – proteins that prevent virus from attaching to your cells and reproducing.

  10. Ways to control viruses: • 3. Antibodies – immune system proteins that attack and kill bacteria and viruses.

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