Ligases are enzymes that link two dna fragments together. Suppose a bacterium develops a mutation in the ligase gene needed for dna replication. This mutation results in an inactive form of the enzyme. What outcome can you expect for this bacterium and why?

Cell will not replicate because of incomplete DNA replication.

Explanation:

DNA replication is crucial for reproduction/replication of any organism as it involves the duplication of genetic material. So if an organism is unable to perform proper DNA replication it would not be able to reproduce.

DNA polymerase is the enzyme that synthesize the new DNA strand in DNA replication. DNA polymerase can synthesize a strand only in 5'→3' direction. Both of the strands of DNA molecules are opposite in direction. So one strand is synthesized continuously called as leading strand while the other strand is synthesized in form of okazaki fragments called as lagging strand.

The okazaki fragments are joined together by the enzyme ligase. So if Ligase enzyme is absent in bacteria it would not be able to synthesize the lagging strand of DNA and thus could not be able to produce a replica of DNA. And if there is No replication of DNA then No replication of cell would occur.

The primary role of Ligase enzyme during replication is to ensure repair of DNA fragments, it ensures recombination of the DNA backbone to form double strands back, and ensure joining together of short DNA fragments.

Answer:

Therefore if there is mutation in the bacteria cell, Ligases role is blocked, thus recombination of each strands to form double strands is prevented and the bacteria will not be able to undergo replication, because single strand formed can not be used to undergo replication.