• A VIRUS is a microscopic particle that gets inside a cell and often destroys the cell.

Viruses are tiny,

they are smaller

than the smallest bacteria.

Red blood cell7500 nm

• Like living things, viruses contain proteins and nucleic acids, but viruses do not act like living things.

• Viruses do not grow, break down food, use oxygen, respond to stimuli, etc.

• Viruses cannot function on their own.

A virus CANCAN REPRODUCEREPRODUCE inside a cell that serves as a HOSTHOST.

A HOST is a living thing that a virus or parasite lives on or in.

So viruses force the host´s cells to make viruses instead of healthy new

cells.

You need to remember that cells can produce all their structures, so in

certain way they are like tiny factories.

- Viruses

1 chain formed

by nucleotides

1 helix

2 chains formed

by nucleotides

2 helix

avian influenzaRNA virus

Tobacco mosaic virus (RNA virus)

Hepatitis B virus (DNA virus)

Polio virus; RNA virus.

HIV Virus(RNA virus)

HIV infection

HIV infection

Variola virus, the cause of smallpox (DNA virus)

Influenza A virus (RNA virus)

T4 bacteriophage (DNA virus).

Bacteriophage (DNA virus)