1. Name the protein produced by B-cells that is able to bind to an antigen.
Answer
Antibody.
2. Name structures A, B and C in the figure below.
Answer
A = Attachment protein,
3. Describe the role of phagocytes in an immune response.
Answer
Phagocytes engulf the pathogen. The vacuole fuses with a lysosome, and lysozymes (enzymes) digest the pathogen. The phagocyte then presents the antigen on its cell surface membrane.
4. The figure below shows the changes in antibody concentration in the blood between a primary and secondary immune response when a person is exposed to a pathogen for the first and second time. Describe and explain the pattern shown on the graph.
Answer
The first response is smaller, slower and more short-lived than the secondary response. In the first response, time is needed for the immune system to react. In the second response, memory cells are already present, so the reaction is faster.
5. HIV only infects helper T cells. Use your understanding of proteins and the structure of cell surface membranes to explain why.
Answer
Attachment proteins on HIV have a specific tertiary structure. Helper T cells have a (glycoprotein) receptor that is complementary to the attachment protein.
6. Name two uses of monoclonal antibodies.
Answer
Targeting medication to specific cell types and medical diagnosis.
7. The antivenom is specific to one type of snake venom and does not work against others. Explain why.
Answer
Antibodies have a specific shape at their receptor site. Only a specific venom fits, while other venoms do not.
8. The antivenom is made by extracting venom from the snake then diluting it. A very small amount of the diluted venom is injected into an animal, such as a horse. A few weeks later, a little more venom is injected. This is repeated several times. The antivenom is made by taking blood from the horse and extracting the antibodies. The venom is injected several times, rather than just once. Explain why.
Answer
This allows memory cells to be made. Secondary response produces more antibodies.
9. If a person is treated with this antivenom it will not protect them against a future bite by the same snake. Explain why.
Answer
Antivenom provides passive immunity. The person does not produce their own antibodies or memory cells.
10. The antivenom cannot be used on the same person a different time. Explain why.
Answer
Antivenom contains horse antibodies, which act as antigens or "foreign" proteins. The person will mount an immune response against the antivenom and will develop memory cells and antibodies specific to it.