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