Question

Match the term with the definition.

interrupted mating replisome plasmid rolling circle mode aneuploidy

A. a protein complex synthesizing new DNA strand B. a technique to conduct Hfr X F- mating C. extrachromosomal circular DNA that can replicate D. a special DNA replication mode an Hfr cell takes when it mates with an F- strain E. 2n + 1 chromosomes in one organism

Answer 1

Answer :

A. A protein complex synthesizing new DNA strand - replisome.

Explanation : The replisome is the complex of replication fork area that contains helicases to unwind the DNA duplex, polymerases to copy the DNA, as well as nucleases and ligases to process the discontinuous stretches of DNA on the lagging strand.

B. A technique to conduct Hfr X F^- matting - interrupt metting

Explanation : No chromosomal DNA is transferred by standard sex factor F. Transfer of chromosome DNA is facilitated by special strains of F^+ integrated into the bacteria chromosome by crossing over. Hfr strains replicate F factor as a part of their main chromosome. Conjunction in Hfr strains begins when F^+ is nicked at the origin, and F^+ and bacteria chromosomal DNA are transferred using the rolling circle mechanism. Recombinations are produced by crossover of the recipient chromosome and donor DNA containing F^+. Begin with two different Hfr strains selected from F^+ X F^- crosses and perform an interrupted matting experiment.

C. Extrachromosomal circular DNA that can replicate - plasmid.

Explanation : A plasmid is a small, extrachromosomal DNA molecule within a cell that is physically separated from chromosomal DNA and can replicate independently. They are most commonly found as small circular, double-stranded DNA molecules in bacteria, however, plasmids are sometimes present in eukaryotic cells.

D. A special DNA replication mode of Hfr cell takes when it mates with an F^- strain - rolling circle mode.

Explanation : In case of bacterial conjunction E.coli cell in Hfr strains begins when F^+ is nicked at the origin, and F^+ and bacterial chromosomal DNA are transferred by a special type of DNA replication where new strands forms by the rolling circle mechanism, it is a process of unidirectional,n acid replication. It can rapidly synthesize multiple copies of circular DNA molecules(plasmid) in bacterial cells.

E. 2n + 1 chromosomes in one organism - aneuploidy.

Explanation : Aneuploidy is the presence of an abnormal number of chromosomes in a cell i.e. extra or missing chromosome. For example human somatic cells with chromosome numbers of (2n-1) = 45 or (2n + 1) = 47 are aneuploid.