Finishing Viruses + Monera Virus: Infection 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 energy3) Living things reproduce4) Living things respond to stimuli5) Living things are homeostatic6) Living things grow and develop7) 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 DefenceFirst 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 DefenceSecond Line of Defence• Circulatory System (fast response)– Leukocytes: Engulfs invader it releases an enzyme

that destroys the invader and itself

Body’s DefenceSecond 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.