Question

Once the chain of the TCR is rearranged and the cell has finished proliferating:

a. The RAG genes are turned back on.
b. Rearrangement of the chain locus is induced.
c. There is a bigger chance that the rearranging thymocyte will become a : T cell than a : T cell.
d. A & B

Answer 1

RAG genes are not reactivated once TCR rearrangement is complete, and further locus rearrangement does not occur. The T cells differentiate to become either CD4+ or CD8+ T cells based on MHC recognition.

Step-by-step explanation:

Once the chain of the T-cell receptor (TCR) is rearranged and the cell has finished proliferating, RAG genes are not turned back on. The rearrangement of the receptor chain locus is not induced again because each T cell receptor is unique to the specific T cell.

Instead, there is a differentiation process that occurs where CD4+ or CD8+ T cells are generated based on the recognition of MHC molecules. The mature T cells do not continue to rearrange their TCRs but are selected for those that have a TCR that can recognize and bind to an antigen presented by MHC molecules.