5.5 - Antibodies

Question 1

Roles of antibodies (3 roles):

Answer 1

1. agglutination of pathogens - clumping of pathogens together to enable easier phagocytosis
2. neutralisation of toxins - when antibodies bind to toxins to inactivate them
3. preventing pathogens from binding - when antibodies bind to pathogens to stop them from infecting body cells

Question 2

Binding site of an antibody:

Answer 2

each antibody has a unique binding site that fits onto a specific antigen - forms an antigen-antibody complex

Question 3

what regions are polypeptide chains made of?

Answer 3

• constant region - same for all antibodies and binds to receptors such as B cells
• variable regions - different for each antibody as its shape is complementary to a specific antigen - part which binds to antigens

Question 4

Antibody structure: (what are the chains held by?)

Answer 4

• Y - shaped glycoproteins made up of 4 polypeptide chains (two heavy and two light)