VIRUSES

WHAT IS A VIRUS?

Virus: a tiny, nonliving particle that invades and then multiplies inside a living cell• Act like a parasite that can

only reproduce inside living cells

ARE VIRUSES ALIVE?

Viruses are not made of cells, so they are not alive.

MADE OF 2 PARTS

1. Protein Coat

2. Genetic Material• DNA or RNA

TYPES OF VIRUSES

Active

Hidden

ACTIVE VIRUSES

Immediately takes over a cell to make new viruses

Bursts when there are so many viruses that the cell breaks

HIDDEN VIRUSES“Hide” by becoming part of host DNA and waits until the conditions are right

At some point, make copies just like an active virus and then go back into “hiding”

DO ANTIBIOTICS WORK?

No! They only can kill bacteria.

…but vaccines can prevent viral infections

VACCINESA vaccine is a substance introduced into the body to stimulate the production of antibodies (chemicals) that destroy specific viruses

Ex: chickenpox vaccine and Flu shot