Viruses

VIRUSES

A person that studies viruses is known as virologist.

A virus cannot be seen with a compound light microscope because it is so small. It can be seen with an electron microscope.

What are some examples of viruses?

• Ebola
• Herpes
• Herpes Virus I
• Herpes Virus II
• Herpes Zoster
• HIV
• Influenza
• Mono

The first virus to be annihilated off of the face of the earth was small pox in 1796. It was also the first virus to have a vaccine. The smallpox vaccine was created by Edward Jenner. A vaccine is a weakened virus or the virus itself without its DNA/RNA.

What are the parts of a virus?

• Head
• Tail
• Capsid (protein shell)
• DNA/RNA
• Tail Fibers

How can you catch a virus?

• Exchanging bodily fluids
• Insect/animal bites
• Inhalation

Symptons:

• Low grade fever (100-101)
• Nausea
• Loss of appetite
• Muscle ache
• Fatigue
• Low white blood cell count

Two life cycles of a virus:

Lytic and Lysogenic

LYTIC

1. Virus attaches to host & inject its DNA into it
2. DNA is replicated by host cell
3. Parts of the virus are created
4. Viruses break out of cell

LYSOGENIC

1. Virus attaches itself to host & inject DNA inside
2. DNA attaches to host DNA
3. DNA replication (interphase)
4. Cell undergoes mitosis
5. "Weird" protein creates outbreak

What does your body do to defend yourself against viruses?

1. White blood cells recognize foreign invaders (antigen)
2. T lymphocytes carry message to other white blood cells to create antibodies
3. Antibodies flock to the antigen & wrap around it (Antibodies are like enzymes, they fit with certain antigens like a lock and the key)
4. White blood cells carry antigen to lymph nodes

Are viruses living or nonliving?

Reasons to believe they are living...

• Contain DNA/RNA
• They replicate
• They're made of lipids, proteins, and nucleic acids
• They undergo mutations

Reasons to believe they are nonliving...

• They do not reproduce
• They need a host
• They don't have a nucleus
• They do not grow
• They do not convert energy