Download viruses! - Science with Mrs. Schulte

VIRUSES!
Viruses
 Tiny
NON-LIVING particle that enters
and then reproduces inside a living
cell.
 Considered to be NON-LIVING
because they are not cells and cannot
make or take in food.
Size of Viruses
Structure of a Virus
 All
viruses have 2 basic parts: a protein
coat that protects the virus and an inner
core made of genetic material.
 Come in different shapes
(but all have those 2 parts)
How Viruses Multiply
 Although
viruses can multiply, they do
so differently than organisms. Viruses
can multiply ONLY when they are
inside a living cell.
 Host: organism that provides a source
of energy for a virus or another
organism.
How Viruses Multiply
1. Virus attaches to a cell
2. Virus injects into genetic material
3. Virus’ genetic material takes over the cell’s
functions. It instructs the cell to produce the
virus’ proteins and genetic material.
4. The proteins and genetic material then
assemble into new viruses.
5. The cell bursts and releases new viruses
Question to consider

If a parasite is an organism that lives on or
inside a host and causes it harm than…How
are viruses different than parasites???
Virus Replication
Infectious Diseases
• Any disease that you can pass on to another
person
• Spread by pathogens which are usually
microscopic and impossible to see
• Spread by vectors, animals that do not actually
get the disease, such as ticks, mosquitos, or
rats
Viral Diseases
Dangers: reproduce quickly, can alter original cell
function
Transmission: depends, some airborne, touch, or
bodily fluids
Examples: HIV/AIDS, Hepatitis, Flu, Cold,
Chickenpox, Ebola, Cold sores
Treatment: No cure for viruses, only vaccines
which are preventative for some viruses
Epidemic
• When a large number of people in an area or
community all become infected with the same
disease
Examples: (pick 2)
• Smallpox in the “New World” in 1500’s
• Flu of 1918
• Swine flu of 2009
Pandemic
An epidemic on a much larger scale, continentwide or world-wide
Examples:
• Black Death (bubonic plague) in 1600’s
• HIV/AIDS in Africa