Q: What are two methods of diversity for the protein sequence of an Ig molecule?
A: Somatic Mutation; where mutations in the coding sequence are inserted during B cell maturation. Recombination; there are many coding sequences that encode the variable region of the Ig protein.

Q: How many different isotypes can one B cell make.
A: ONE!!! A single B cell makes a single heavy chain protein. (monoclonal)

Q: Describe the concept of monoclonal (this was bold and underlined so know this!!!)
A: For any given B cell, its product is a single Ig protein made up to two identical light and two identical heavy chain proteins. 

Q: What is VDJ anyway?
A: Variable, Diversity, and Junctional coding sequences in the gene. The sequences between these are removed to have one V, one D, and one J come together to form a single VDJ coding sequence.

Q: Which chain is made first, heavy or light?
A: Heavy

Q: What regions do light chains have, (only two). 
A: Variable and joining, NO DIVERSITY.

Q: What enzyme inserts DNA sequences at the junctions of V, D, and J regions?
A: Terminal Transferase. (adds single nucleotides generating more diversity).

Q: What is class switching?
A: generating different isotypes by altering the HEAVY CHAIN ONLY.

Q: In what order are the different isotypes of Ig chains made?
A: IgM, IgD, IgG, IgA, IgE

Q: How does antigen specificity change during class switching?
A: IT DOESN'T

Q: How many chances does a B cell have to obtain productive VDJ maturation?
A: 2 chances in the heavy chain and four chances in the light chain (kappa, and lambda).

Q: What is the Rag enzyme used for?
A: it facilitates VDJ rearrangement by recognizing the RSS (recombination signal sequence).