Question

Some temperature-sensitive bacterial mutants stop replication immediately following elevation of temperature, whereas others continue to replicate their DNA for a period of time before they cease this activity, and still others continue until a round of replication is completed. How might these three types of mutants differ?

Answer 1

These mutants may differ in the following way:

• Stop replication immediately: mutation in MCM gene due to which it gets exported quickly and senses heat. This will immediately stop replication as mcm proteins are licensing factors for replication.
• Continue at elevated temperature: mutation in MCM gene such that it cannot detect or sense elevated temperature. Or if the MCM protein cannot be exported to cytoplasm.
• One round only: normal cells (silent mutation)