Virus Life Cycle

Editor: Lindsey Lightman, Grace Kim
Publisher/Researcher: Joe Lim
Researcher: Joanna Mabine :D, Adam Jurado

Virus: living aspects include: that they mutate and reproduce quickly, but only in host cells.
Nonliving aspects include: no metabolism, no cytoplasm or cellular components, and they have DNA or RNA, but not both.

Please be sure to use the correct question. e.g.
Viruses Format: (P8/9)
1. Virus Life Cycle
(6 steps are listed below)

2. Three examples of a Virus in organisms
a. Oral Herpes (Herpes simplex): forms blisters around the mouth and can go dormant or no longer be dormant at ant time. It spreads through all of the skin on a person, so the blisters can show up anywhere.
b. Shingles (Herpes zoster): this is caused by the virus that causes chickenpox. If you get chickenpox, shingles can show up later because the virus may be dormant or not dormant whenever.
c. Yellow Fever (Flaviridae Genus): This is spread by mosquitoes and has three stages, but only the third tends to be deadly. The first and second stages have typical flu symptoms like headache, flushing and fever. The third stage involves organ failure, even the brain. Comas and death can occur, and the heart, kidney and liver are often affected.

3. Genus species name of organism infected
Homo sapiens sapiens (humans) are the organisms most commonly affected by Flavivirus yellow fever, Herpes zoster and Herpes simplex.

4. Picture of organism with and without virus
With: (Flu Virus)
Flu Royalty Free Stock Photo
Flu Royalty Free Stock Photo

With - (H1N1)
h1n1 virusRoyalty Free Stock Photo
h1n1 virusRoyalty Free Stock Photo

Without/About to !
Human cell and virus cells Royalty Free Stock Photo
Human cell and virus cells Royalty Free Stock Photo

5. Effects of virus on organism
external image moz-screenshot-2.pnghiv2.jpg
Part 1: Virus Life Cycle
1) Virus Attaches to Host Cell: cells must have receptors on their surface for the virus to infect it. These receptors must have a portion on their surface that chemically resembles the virus’s surface.

2) Virus Enters the Cell:

the viral envelope can fuse with the cell membrane and get released into the cytoplasm, but the virus usually enters through endocytosis. This protects the virus from the cell.

3) Virus Moves to Site of Replication:

The pH of the virus decreases, which allows the virus to leave its compartment during endocytosis. The virus leaves through one of these processes:

Lysis of the Virus: this happens after endocytosis and released the nucleocaspid from the virus into the host cell. A nucleocaspid is made up of the viral proteins.

Fusion of the Virus Compartment With the Cell Membrane:

The viral envelope fuses with the cell membrane, to release the nucleocapsid, without the virus envelope entering the cell.

The Virus undergoes Conformational Changes:Pores in the endocytic vesicle form so the virus can enter the host cell's cytoplasm.

4) Virus Replicates and Assembles Itself:
The viral genome directs the cell to make copies of the virus. The viral DNA transcribes itself into mRNA, which goes to the host cell’s ribosomes to create copies of itself.

5) Virus Leaves the Cell:
The virus is released by host cell lysis by disintegrating the membrane. If the virus is enveloped, it might not lyse the cell.

6) Cell Infects Other Cells With the Virus:
The virus is released by host cell lysis by disintegrating the membrane. If the virus is enveloped, it might not lyse the cell.
6. Animations that may be helpful

Bibliography using MLA citation. Please refrain from using Citation Machine or other thoughtless citation sites.


Physical Description
Job Description
The virus attaches, then enters into the host cell and goes to the site of replication to release copies of itself. It then matures and assembles itself, then leaves the cell. The cell then releases copies of itself with the virus, going through the reinfection cycle.

Where the molecule is formed: viruses are formed outside of the host cell. During the lytic cycle, the host DNA is digested in the cytoplasm. During the lysogenic cycle, the phage DNA inserts itself among the host cell's DNA instead of replacing it entirely.
Where the molecule is in the cell: Flavivirus yellow fever used the lytic cycle, Herpes simplex uses the lytic cycle and Herpes zoster uses the lytic cycle too. This means all of these viruses are in the host cell DNA to replace it. However, all forms of the herpes virus only go through the lytic cycle immediately after infecting a human. They later undergo the lysogenic cycle when traveling through the nervous system and remaining in the nerve fibers. It is there that the host cell DNA is replaced.
How does the molecule work?: Flavivirus yellow fever, Herpes simplex and Herpes zoster work using the lytic cycle.
Works Cited:

Lytic cycle: HIV, influenza
Lysogenic cycle: Streptococcus pyogenes, Shigella dysenteriae, Vibrio cholerae, and Corynebacterium diphtheriae