Antibodies quiz

1. What is antibody affinity?
The strength of the bond between one variable region of an antibody and the antigen
2. What is avidity?
The overall strength of an antibody to an antigen
3. What is valency?
The number of antibodies that can attach to an antigen at once
4. What is a conformational binding site?
The binding site of the antibody depends on the antigen’s 3D structure and would be nonviable if its conformation changed
5. What are the types of antibody binding site shapes?
Pockets, grooves, protruding surfaces and extended surfaces
6. What are the types of bonds between antibody and antigen?
Hydrogen, ionic, hydrophobic and Van der Waals
7. What are the classes of antibody and what do they do?
IgA, IgE, IgG, IgD and IgM
8. What does each class do?
a. IgA = protects areas exposed to the outside
b. IgE = allergic and parasitic response through cross-linking histamine release
c. IgG = most common, circulates in the blood
d. IgD = activates basophils, mast cells and B cells
e. IgM = the first antibody produces in response to a new antigen
9. Describe an IgG molecule (structure)
Hinge region with two lower disulphide bonds
10. Describe an IgD molecule
Hinge region with one lower disulphide bond
11. Describe an IgE molecule
No hinge region, an extra constant region instead, one disulphide bond above and one
below it
12. Describe an IgA molecule
Two IgD molecules bound to each other through a J chain
13. Describe an IgM molecule
5 IgE molecules bond in a ring with one J chain and no lower disulphide bond
14. What enzymes break down immunoglobulin?
Papain (produces 2 Fab segments) and Pepsin (1 Fab section)
15. What do Fab and Fc stand for?
‘Fragment antigen binding’ and ‘Fragment crystallisable’
16. How do antibodies defend the body?
a. Neutralise toxins
b. Neutralise whole viruses/bacteria in the extracellular space for phagocytes
c. Activate complement for direct lysis (MAC) and opsonisation
17. Which immunoglubulins can activate complement and why?
IgG and IgM because they circulate around the body
18. How do you produce antibodies in a lab?
a. Immunise mouse with antigen to produce B cells
b. Harvest spleen B cells OR serum monoclonal antibodies (for polyclonal production)
c. Hybridise with myeloma to form hybridoma
d. Choose hybridoma and collect the antibodies
19. How do you purify the antigens?
a. Attach monoclonal antibody to insoluble matrix (e.g. sepahrose beads)
b. Pour protein mixture down column, antibody will bind to antigen
c. Elute antigen with pH change
d. Test with western blot
20. How are antigens presented?
a. Antigen ingested via endocytosis
b. Broken down in endoxome with lysozyme
c. Bound to class II MHC
d. Complex is presented on cell surface via exoctosis
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