Antibodies

• What are antibodies?


  Proteins with specific binding sites synthesised by B cells.
• What protein structure do antibodies have?

  Quaternary.
• When does the body produce antibodies?

  When it is infected with a pathogen.
• How does a specific antibody react with an antigen?

  By binding to it.
• What are the antigen binding sites complementary to?


  A specific antigen.
• How are the massive numbers of antibodies possible?

  They are made of proteins which occur in an almost infinite amount.
• How many polypeptide chains do antibodies have?

  4
• What are the polypeptide chains in an antibody called?

  The long pair are called heavy chains while the shorter pair are called light chains.
• What does each antibody have?

  A specific binding site that fits very precisely onto a specific antigen.
• What is formed when an antibody binds to an antigen?

  An antigen-antibody complex.
• Where is the variable region on an antibody and why?

  The binding site as it is different on different antibodies.
• What is the constant region of an antibody and why?

  The part of the antibody that is not the binding site, as it always stays the same.
• What does the constant region of an antigen bind to?

  Receptors on cells such as B cells.
• What do antibodies do and don't do to an antigen?

  Prepare it for destruction but not destroy it directly.
• What two ways do antibodies prepare antigens for destruction?

  Cause agglutination of the antigen, and serve as markers that stimulate phagocytosis on the antigen.
• What is agglutination?


  The clumping of antigens to make it easier for phagocytes to locate them as they are less spread out within the body.