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Virus: Section 3
Teacher Notes
Virus
A microscopic particle that gets inside a cell and destroys the cell.
Contains DNA or RNA, and sometimes both.
Viruses cannot eat, grow, break down food, or use oxygen.
Viruses must have a host to survive.
4 Shapes
1. Crystals
2. Cylinders
3. Spheres
4. Spacecraft
DNA
Genetic material of a virus or bacteria.
RNA
Genetic material of a virus.
Host
An organism from which a parasite or virus takes food or shelter.
Using the host’s cell as a tiny factory, the virus forces the host to
make viruses rather than healthy new cells.
Lytic Cycle
The active cycle of virus reproduction.
1. Virus finds a healthy cell.
2. Virus connects DNA or RNA to healthy cell.
3. Healthy cell is turned into a virus factory.
4. New viruses break out of cell and cycle repeats.
Lysogenic Cycle
As the host cell divides, each new cell gets a dormant copy of the
virus’s DNA or RNA.
Antiviral
Medicine used to kill viruses.
Homework – Virus Section 3
Using Key Terms
1. Use the following terms in the same sentence: virus and host.
1. Viruses must have a host to survive.
Understanding Key Ideas
2. One characteristic viruses have in common with living things is that they
a. eat
b. reproduce
c. sleep
d. grow
3. Describe the four steps of the lytic cycle.
3a. Virus finds a healthy cell.
3b. Virus attaches DNA or RNA to healthy cell.
3c. Healthy cell becomes virus factory.
3d. Viruses break out of cell and cycle repeats.
4. Explain how the lyctic cycle and the lysogenic cycle are different.
4. Lyctic cycle is how viruses reproduce. Lysogenic cycle is when the virus’s DNA
or RNA is dormant and is copied in healthy cells. After a period of time the cell
would begin the lyctic cycle.