THE MOLECULAR BASIS OF INHERITANCE
DNA REPLICATION
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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Helicase
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Topoisomerase
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Ligase
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DNA Polymerase
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Detailed explanation-1: -DNA gyrase introduces supercoils, and DNA topoisomerase I prevents supercoiling from reaching unacceptably high levels.
Detailed explanation-2: -Type II topoisomerases can convert a single positive supercoil into a negative supercoil. Thus the linkage number is reduced by two (-2) in a single step. Type II topoisomerases are involved in both decatenation of daughter chromosomes, and relieving the positive supercoiling ahead of the replication fork.
Detailed explanation-3: -In eukaryotes, TopIB and TopII enzymes provide the major DNA relaxation activities during transcription and replication to remove positive and negative supercoils.
Detailed explanation-4: -In addition, these enzymes fine-tune the steady-state level of DNA supercoiling both to facilitate protein interactions with the DNA and to prevent excessive supercoiling that is deleterious.