Download Virus and Immune Response

Virus: Infection
Finishing Viruses + Monera
and
Immune Response
Viruses Living or Not
Remember the 7 characteristics of living things:
1) Living things are organized (Hierarchy of levels)
2) Living things acquire materials and energy
3) Living things reproduce
4) Living things respond to stimuli
5) Living things are homeostatic
6) Living things grow and develop
7) Living things can adapt to their environment
Problem with Viruses as Living
Outside a cell: Lifeless molecule. Cannot carry
out any of the 7 life functions
Inside a cell: It is able to reproduce
(3. Living things reproduce)
Where do Viruses fit: Between living and
nonliving things
Human/Animal Defense
First Line of Defence:
• physical barriers
(always active)
– Skin: Prevents
invaders from
entering body
– Mucus: In lungs it
traps invaders and
debris
Body’s Defence
First Line of Defence:
• physical barriers (always active)
– Skin: Prevents invaders from entering body
– Mucus: In lungs it traps invaders and debris
– Cilia: Small hairs that sweep
debris up and out of the
respiratory pathway
– Stomach acid: Provides a toxic
environment that kills invaders
Body’s Defence
First Line of Defence:
• physical barriers (always active)
– Skin: Prevents invaders from entering body
– Mucus: In lungs it traps invaders and debris
– Cilia: Small hairs that sweep debris up and out of the
respiratory pathway
– Stomach acid: Provides a toxic environment that kills
invaders
– Tears: Contains lysozyme, an enzyme that destroys
bacterial cell walls
Body’s Defence
Second Line of Defence
• Circulatory System (fast response)
– Leukocytes: Engulfs invader it releases an enzyme
that destroys the invader and itself
Body’s Defence
Second Line of Defence
• Circulatory System (fast response)
– Leukocytes: Engulfs invader it releases an enzyme
that destroys the invader and itself
– Complementary Proteins: Proteins always present
in the circulatory system that are usually in an
inactive form. They are activated by antigens
(Foreign marker proteins : Spikes)
Body’s Defence
Third Line of Defence
• Antibodies (Slow response, long term)
– Lymphocytes (White blood cell): Produce
antibodies that attach to specific antigens
(Markers or spikes) This allows the immune
system’s white blood cells to identify and destroy
them
Vaccines and Immunity
Vaccine: A dead, weak or inactive version of a
virus or other infectious microbe that is
introduced into the body.
Immunity using Vaccine:
Vaccines and Immunity
Vaccine: A dead, weak or inactive version of a
virus or other infectious microbe that is
introduced into the body.
Immunity using Vaccine: Specialized white
blood cells produce antibodies that attack the
dead virus. This way the body will be
protected when the real virus infects the body.
The body has already made an antibody
against it
Assignment
Virus Research Project intro.