Exam 4 UAB BY123

What is a virus?

-an infectious particle consisting of genes packaged in a protein coat

-much simpler in structure than even prokaryotic cells

-cannot reproduce or carry out metabolism outside of a host cell

How was viruses discovered?

Tobacco Mosaic Virus (late 1800s)

Wendell stanley

1. extracted sap from tobacco plant with tobacco mosaic disease

2. Passed through a porcelain filter known to trap bacteria

3. Rubbed filtered sap on healthy tobacco plants 4.Healthy plants became infected

How can viruses reproduce?

-Only reproduce within living cells

-Require a host cell for replication

Do all living organims have viruses?

Yes. Prokaryotes and all varieties of eukaryotes have viruses.

Bacterial Viruses

bacteriophages