How does the immune system recognize diverse possible antigens? •How do antibodies simultaneously recognize a huge variety of antigens and carry out a limited number of effector functions? •What is V (D) J recombination? What do the letters (and parentheses) signify? •What is the 12/23 rule? •What are RAG-1/2 and TdT? What do they recognize? What do they do? •What changes at the Ig loci are required to switch from membrane-bound to secreted Ig?

check the explanations

Explanation:

1. - The immune system recognize antigens because both are complementary proteins, they match like in a puzzle, just to the exact shape and not to another that is similar.

2. - Since each antibody has a different shape, that is unique, so it will recognize just one kind of protein.

3. - Variable (diversity) joining, is a genetic recombination that occurs in the lymphocytes to produce antibodies.

4. - The rule 12/23 is apply when a protein is in the process of recombination of the DNA, if the recombination occurs in just one chain so just 12 basepairs are working, but if there are 2 strains, then 23 basepairs are included.

5. - The recombination activation gene (RAG) codify enzymes for the reorder and recombination of the inmunoglobine and the linphocytes T.

6. - Is a Loci in the genetic code for a cancer gene, could be turn "off" and when is in contact with some factors could be "on" and produce cancer.