31.4 Immunity and Technology KEY CONCEPT help keep a person healthy.

31.4 Immunity and Technology
KEY CONCEPT
Living in a clean environment and building immunity
help keep a person healthy.
31.4 Immunity and Technology
Many methods are used to control pathogens.
• Antibiotics and antiseptics cause pathogens to burst.
31.4 Immunity and Technology
• Antiseptics kill pathogens outside of the body.
– do not target specific pathogens
– examples include vinegar and soap
• Antibiotics kill pathogens inside the body.
– target one specific bacterium or fungus
– not effective against viruses
31.4 Immunity and Technology
• Antibiotic resistance can cause medicines to become
ineffective.
– Some bacteria in a population have genes that make
them immune to antibiotics.
– These bacteria spread the gene, making the antibiotics
useless.
A bacterium carries
genes for antibiotic
resistance on a plasmid.
A copy of the plasmid is transferred
through conjugation.
Resistance is quickly
spread through
many bacteria.
31.4 Immunity and Technology
Vaccines artificially produce acquired immunity.
• Vaccines also control pathogens and disease.
– given to prevent illness
– contain the antigen of a weakened pathogen
31.4 Immunity and Technology
• Vaccination provides immunity.
– stimulates a specific
immune response
memory B cells
– causes memory
cells to be produced
– allows immune
system to respond
quickly to infection
– has such a fast
response, a person
will not get sick
Antigens in a vaccine
trigger an immune response,
and memory B cells are
made.
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A memory B cell is
stimulated when the real
pathogen binds to it.
The B cell quickly activates
and makes antibodies that
fight the pathogens before
you get sick.