viruses pa state standards:. what are viruses? 1) a nucleic acid (dna or rna) surrounded by a coat...

VIRUSES

PA State Standards:

What are VIRUSES?

1) A nucleic acid (DNA or RNA) surrounded by a coat of protein.

2) Viruses are not considered to be alive (they are not in one of the five kingdoms).

Nonliving Properties of Viruses

1) Not made of Cells (no organelles or cell functions).

2) Can’t grow or reproduce on their own (reproduce inside the cells of other

organisms).

3) Can be crystallized & stored for years.

Examples of Viruses:Bacteriophage

Head

Tail

Capsid

DNA

Tail Fibers

Examples of Viruses:

Influenza VirusCapsid

RNA

Proteinspikes

What is a parasite

An organism that attaches itself and feeds off of another organism.

A parasite does harm to the organism it is attached to

Hookworm

What is a host

The organism that is harmed or hurt by the parasite

Example: You are the host to a mosquito

Bacteriophage Reproductive Cycle

1- Attach

Virus attaches to cell. Use tail to attach to cell membrane of cell.

Bacteriophage

Bacteria

2- Invade

Viral DNA invades cellVirus injects nucleicacid into the cell.

Viral DNA penetrates cell membrane/cell wall

Viral DNA slides into host cell

3- Copy

a) Virus’ nucleic acid attaches to DNA of the cell.

Viral DNA

Bacterial DNA

Bacteria is forced to make more & more viruses

3- Copy

b) DNA copies and makes new virusesVirus takes control of cell & makes new virus particles.

4- Release

Cell bursts releasing hundreds of new viruses

Bacteriophage Reproductive Cycle

5- VIRUSES & DISEASE

1) HUMANS

a) Colds

b) A.I.D.S.Aquired Immune Deficiency

SyndromeH.I.V. – Human Immunodeficiency Virus

5- VIRUSES & DISEASE

1) HUMANS

c) Polio

Iron Lung

F.D.R.Deformed Leg

Caused by Polio

5- VIRUSES & DISEASE

2) ANIMALS

Rabies

5- VIRUSES & DISEASE

3) PLANTS

Tobacco Mosaic Virus

How are viruses transmitted?

Direct contact Touching, body fluids, etc.

Vectors - mosquitoes, flies, etc

Airborne Spread by the air

Terms to know:

What happens when a disease spreads fast in a certain area?

An epidemic What system in your body is used to help stop

you from getting sick? The immune system What is a small amount of a virus injected into

your body to give you immunity called? A vaccine

CREDITS

http://www.cat.cc.md.us/courses/bio141/lecguide/unit2/viruses/lysosum.html