Question

Which of the following is true about a merozygote?

A) It can spontaneously form from an Hfr cell.
B) Merozygotes were crucial to our understanding of the formation of the sex pilus.
C) A merozygote can form if an F factor carries chromosomal DNA and is injected into an F cell.
D) A conjugation with an Hfr donor will never produce a merozygote.
E) It is formed from an Hfr to F+ cross.

Answer 1

A merozygote can form if an F factor that carries chromosomal DNA from an Hfr cell is transferred into an F-cell during conjugation, resulting in a cell with genes from both its own chromosome and the transferred chromosomal DNA.

Step-by-step explanation:

A merozygote is an organism or cell that is partially diploid due to the presence of an extra-chromosomal element, such as an F' plasmid carrying chromosomal genes. This condition can occur if the integrated F plasmid (the F factor) is imprecisely excised from the bacterial chromosome of an Hfr cell, bringing along with it some adjacent chromosomal DNA. This F' plasmid can then be transferred into an F-cell during conjugation, resulting in a merozygote that contains genetic material from two different sources.

Therefore, the correct statement about a merozygote is: C) A merozygote can form if an F factor carries chromosomal DNA and is injected into an F-cell. This is a result of the integration and subsequent imprecise excision of the F plasmid from the chromosome, which may then carry chromosomal genes into the recipient F-cell. The resulting cell will have two copies of some genes: one from its own chromosome, and one from the donated chromosomal DNA that is now part of the extrachromosomal F' plasmid.