immunity Flashcards
what is immunity
collective defences of the body that provide resistance to infection or disease
distinguish between the non-specific defences and the specific defences
innate immunity: no immune memory
-> responds the same way to all pathogens
adaptive immunity: immune memory
-> targeted specific responses to particular pathogens
what is the first line of defence
physical, chemical and biological barriers that have evolved to block pathogens from entering the body
- preventative mechanism
what is the role of physical barriers in the first line of defence?
blocking/stopping pathogen entry
what is the role of chemical barriers in the first line of defence?
production of harmful substances
- actively harms pathogen= inhibits growth development
what is the role of biological barriers in the first line of defence?
helpful bacteria
-> competed with other bacteria
how do plants protect themselves against pathogens?
structural and biochemical characteristics
- no distinct immune system
compare the roles of natural killer cells and cytotoxic t cells in response to a virus
4 marks
- signal infected cells to undergo apoptosis
- nkc= innate immune response
- = non-specific+ act early in 2nd line of defence
- Tc= adaptive immune response
- = specific+ act later in 3rd line of defence