Temperature-sensitive (ts) mutations, which are one form of conditional lethal mutations, allow cells to grow at one temperature but not at a higher temperature. A large number of ts replication mutants have been isolated in bacteria. These mutant bacteria are defective in DNA replication at 42oC but not at 30oC. If the temperature of the medium is raised from 30 to 42oC, these mutants stop making DNA in one of two ways. The quick stop mutants halt DNA synthesis immediately, whereas the slow stop mutants stop DNA synthesis only after many minutes. Predict which of the following proteins, if temperature sensitive, would display quick stop and which would display a slow stop phenotype. Explain each prediction. 5 points total
a. DNA topoisomerase I
b. Single strand DNA-binding protein
c. DNA helicase
d. DNA primase
e. DNA ligase