1	Viruses
2	What is a Virus? - Definition: nonliving particle that contains DNA (or RNA) which can replicate (make copies) only with the help of a host cell.
3	Yes, but really, what is a virus… - The word 'virus' is from the Latin term for 'poisonous substance'. - A virus has been described as a 'piece of bad news wrapped up in protein'. - Viruses can - - Exist outside a cell or inside a cell - - Pass genetic information onto a cell or take genetic information from a cell - - Destroy or damage host cells (the cells that it infects)
4	What is a virus made of? - Capsid - outer protein coat that protects the nucleic acids in the inner core. - Inner core - where nucleic acid (DNA or RNA) is located.
5	What are viruses made of con't - Envelope - similar to plasma membrane but has projections that help it get into a host cell. Only found on some viruses. - Tail - used for attachment to host cell. Only found on some viruses.
6	More about viruses -The shape/make up is determined by the genetic material (nucleic acid). -The shape/make up determines what host cells can be infected and how the virus will affect the cell.
7	Why are viruses NON-living? They do not have the ability to replicate by themselves. (Reproduction)
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9	Why else are viruses NON-living? -They do not have ribosomes so they cannot make proteins (Growth and development and Homeostasis)
10	What is a Host Cell? - Definition: A cell in which a virus can replicate (make copies of itself). - The host cell is often destroyed in the process.
11	How does a virus infect a host cell? - Attachment - proteins in the tail fibers, envelope, or capsid interlock with matching proteins on a host cell. (Called receptor sites)
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14	How does a virus infect a host cell? Enters the host cell - either the virus injects the DNA/RNA directly into the cell or the entire virus is engulfed by... -Endocytosis
15	Two ways that a virus can behave once it is inside the cell. - It can immediately begin the process of replication. Called the lytic cycle. - It can enter and become part of the host cells chromosomes (DNA) and be copied and passed to new daughter cells when the host cell performs mitosis. Called the lysogenic cycle (It can then later enter the lytic cycle).
16	Lytic Cycle Process Entry - Nucleic acid (DNA or RNA) is injected into the host cell.
17	Lytic Cycle Process Con't - Replication - The viral DNA takes over the 'machinery' of the host cell and begins to make copies of itself, including the proteins used to make the new viruses.
18	Lytic Cycle Process Con't - Assembly - The new parts are assembled into new viruses inside the cell.
19	Lytic Cycle Process Con't - Lysis & Release - the host cell breaks open and releases the new virus particles.
20	The Lytic Cycle
21	Lysogenic Cycle - Attachment and Entry in the lysogenic cycle is similar to the lytic cycle. - What happens after the nucleic acid enters the host cell is different.
22	Lysogenic Cycle Provirus formation - the viral nucleic acid is called a provirus when it becomes part of the host’s chromatin.
23	Lysogenic Cycle con't - Cell Division - even though the virus is not active it is replicated along with the host cell's DNA. Each new daughter cell contains the replicated viral DNA. - This process continues indefinitely until...
24	Lysogenic Cycle con't - The provirus leaves the host cell's DNA and becomes active called Induction - This is now the lytic cycle!
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27	Retroviruses - Definition: Viruses that contain RNA (not DNA) and also become proviruses in their host cell. - Most complicated form of replication - The RNA must first be translated into DNA. This is done with reverse transcriptase (an enzyme) which comes from the viral capsid.
28	Retroviruses con't - Retroviruses do not rupture the cells. They exit the cell by - EXOCYTOSIS! - The plasma membrane becomes their new envelope.
29	Retrovirus Infection Cycle
30	Ailments Caused By Lytic cycle Viruses -Common flu -Measles
31	Ailments Caused By Lytic cycle Viruses - Remember that Lytic cycle viruses begin replicating as soon as they enter a host cell. - That's why when you are exposed to the flu virus you get sick within 5-10 days. (depending on the strain of flu virus)
32	Ailments Caused by Lysogenic Cycle Viruses - Shingles - HIV (also a Retrovirus!) - Herpes - Cold sores - Genital herpes - Hepatitis B
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35	Bacteriophage - Definition: a virus that infects bacteria only. - Abbreviated PHAGE.
36	FMI - http://en.wikipedia.org/wiki/Virus - http://www.virology.net/garryfavwebindex.html - If the links don't work when you click on them...right click on the link and select "Open Hyperlink". For a cool video clip check out the following link. - http://www.hybridmedicalanimation.com/illust_bacteriophage.html - Click on hybrid promotional reel to view.
37	Works Cited - Biggs, Alton, Kathleen, Ph.d. Gregg, Whitney C. Hagins, and Et Al . Biology the Dynamics of Life. New York: Glencoe McGraw-Will, 2000. - Virology on the WWW. 28 Apr. 2006 <http://www.virology.net/garryfavwebindex.html>. - "Viruses." Wikipedia. 4 Apr. 2006 <http://en.wikipedia.org/wiki/Virus>. - Images are cited in text.