Which of the Following is True Regarding Alpha Complementation

Question

Which of the following is true regarding alpha complementation?
A)The plasmid encodes the amino terminal of $\beta$-galactosidase while the host bacterium encodes the carboxyl portion .
B)The plasmid encodes both amino and carboxyl terminals of the lacZ region.
C)The complete $\beta$-galactosidase enzyme is made by the host.
D)When the alpha and beta regions fuse they form an inactive peptide.

Accepted Answer

Alpha complementation occurs when two fragments of the reconstituted F1F1F1S1F1F1F10-galactosidase enzyme are encoded by two different sources. The plasmid encodes the amino terminal (α-fragment) while the host bacterium encodes the carboxyl portion (ω-fragment). When these two fragments come together, they form an active enzyme to hydrolyze lactose. Therefore, option A is the correct choice since it correctly describes the roles of the plasmid and host bacterium in alpha complementation.