Topic 10 Immune System: Complement System

Question 1

• The complement system accomplishes exactly what it sounds like. It contains ~30 complement proteins that circulate the body and assists in activating the immune response. The proteins circulate in an inactive state and are activated by a substance on microbe surfaces. This activation results in a cascade that attracts phagocytes to foreign cells and helps destroy them by promoting cell lysis.

Answer 1

Note

Question 2

• These are secreted by cells invaded by viruses/pathogens that stimulate neighboring cells to produce proteins to defend against the virus. These are also believed to be regulators of the complement system. The image below is far more complex than what you’ll need to know for the DAT, but it provides a good visual to understand how an invading pathogen stimulates an immune response

Answer 2

Interferons