1. The student is expected to: 4C compare the structures of viruses to cells, describe viral reproduction, and describe the role of viruses in causing diseases such as human immunodeficiency virus (HIV) and influenza

2. KEY CONCEPT Infections can be caused in several ways.

3. Viruses, bacteria, viroids, and prions can all cause infection.
Any disease-causing agent is called a pathogen.
1 nanometer (nm) = one billionth of a meter
100 nm
eukaryotics cells 10, ,000 nm
viroids nm
viruses nm
prokaryotics cells ,000 nm
prion 2-10 nm

4. A virus is made of DNA or RNA and a protein coat.
non-living pathogen
can infect many organisms
A viroid is made only of single-stranded RNA.
causes disease in plants
passed through seeds or pollen

5. A prion is made only of proteins.
causes misfolding of other proteins
results in diseases of the brain