Antigens and Antibodies

• What should you be able to describe by the end of this video?

  Antigens, antibodies, and their roles
• What does the specific immune system include?

  Antibodies and lymphocytes like B and T cells
• How does the specific immune system respond to pathogens?

  In an individual way for each pathogen
• What happens after the specific immune system defends against a pathogen?

  It produces a more effective response next time
• What do scientists refer to molecules on cell surfaces as?

  Antigens
• How does the immune system view antigens on pathogens?

  As foreign or non-self
• What triggers an immune response?

  Detection of foreign antigens
• Why do antigens on body cells not trigger an immune response?

  They are identified as self by the immune system
• What are antibodies also referred to as?

  Immunoglobulins
• What is the structure of an antibody molecule?

  Four polypeptide chains: two heavy and two light
• What holds the chains of an antibody together?

  Disulfide bridges
• How many antigen binding sites does an antibody have?

  Two
• What is formed when antigens bind to antibodies?

  An antigen-antibody complex
• What does the tertiary structure of the antigen binding site do?

  It fits perfectly with the antigen