NEET BIOLOGY

Detailed explanation-1: -The untwisting of the double helix by helicase causes additional twisting of the DNA molecule ahead of the replication fork. Topoisomerase is the enzyme that helps to relieve this strain by breaking, untwisting and rejoining the DNA strands.

Detailed explanation-2: -Topoisomerases play critical roles in DNA replication, transcription, and chromosome structure by altering the topological state of DNA, . These enzymes are capable of relaxing supercoiled DNA and of decatenating interlocked DNA (Fig.

Detailed explanation-3: -Topoisomerase enzyme breaks, swivels, and rejoins the parental DNA ahead of the replication fork, relieving the strain caused by unwinding of the DNA molecule.

Detailed explanation-4: -Topoisomerases are crucial enzymes for many fundamental aspects of neural function. Their primary functions-to cleave DNA strands in order to provide torsional-stress relief or to untangle replicating DNA-provide essential cellular controls during replication and transcription.

Detailed explanation-5: -Replication fork helicases unwind DNA at a replication fork, providing polymerases with single-stranded DNA templates for replication. In bacteria, DnaB unwinds DNA at a replication fork, while in archaeal and eukaryotic organisms the Mcm proteins catalyze replication fork unwinding.