5.5 Antibodies

Question 1

Define antibodies

Answer 1

Proteins with specific binding sites synthesised by B cells

Question 2

Describe the structure of antibodies

Answer 2

• Four polypeptide chains
  -Two heavy chains and two light chains
• Variable region (binding site)
  -Each binding sites consists of a sequence of amino acids that form a specific 3D shape that binds to the antigen to form an antigen-antibody complex
• Constant region

Question 3

How does the antibody lead to the destruction of the antigen?

Answer 3

• Cause agglutination of bacterial cells. Clumps of bacterial cells are formed making it easier for phagocytes to locate them.
  -They then serve as markers that stimulate phagocytes to engulf the bacterial cells

Question 4

How can monoclonal antibodies treat cancer?

Answer 4

-Monoclonal antibodies are produced that are specific to antigens on cancer cells
-These antibodies attach themself to the receptors on cancer cells
- They attach to the surface of the cancer cells and block the chemical signals that stimulate their uncontrolled growth

Question 5

What are some of the ethical issues with the use of monoclonal antibodies?

Answer 5

• often tested on animals
• may have unknown side effects