Question

What enzyme is responsible for the random excision of variable gene segments making up an antibody light chain in DNA?

a) DNA polymerase
b) RNA polymerase
c) DNA ligase
d) RAG enzyme

Answer 1

DNA recombinase is the enzyme that randomly excises V and J segments from germ-line B cell DNA, enabling the creation of diverse antibodies.

Step-by-step explanation:

The enzyme responsible for the random excision of variable gene segments making up an antibody light chain in DNA is called DNA recombinase. This enzyme selectively excises variable (V) and joining (J) segments from the genomic DNA of germ-line B cells. The process involves splicing one V segment to one J segment which, during RNA processing, creates a unique variable region for each antibody. Such genetic rearrangement enables a vast diversity in the antibodies that can be produced by the immune system, allowing it to respond to a wide array of antigens.

The enzyme responsible for the random excision of variable gene segments making up an antibody light chain in DNA is the RAG enzyme. As germ-line B cells mature, the RAG enzyme randomly excises V (variable) and J (joining) gene segments from the light chain gene. This recombination and splicing process results in an enormous diversity of antibody molecules.