Final answer:
Unwinding the double helix of DNA requires an input of energy to break the hydrogen bonds between the base pairs, involving enzymes like helicase and the use of ATP. The necessary unwinding occurs only at specific replication or transcription sites, making it an energy-dependent process.
Step-by-step explanation:
The process of unwinding the double helix of DNA does indeed require an input of energy. This energy is necessary due to the hydrogen bonds that stabilize the base pairs at the interior of the double helix. Enzymes such as helicase are instrumental in this process as they unwind DNA at the origin of replication. However, helicase alone is not sufficient; it requires energy in the form of ATP to break these bonds and initiate unwinding. Once the DNA strands are partially opened, DNA binding proteins (DBPs or SSPs) help to keep the strands separated. Additionally, DNA gyrase, a type of topoisomerase, prevents the duplex DNA from completely unwinding by introducing negative supercoils into the DNA. This complex process ensures that the DNA strands are only unwound at specific places where replication or transcription is needed, making the unwinding process an energy-dependent one.
Therefore, the correct answer to the question, "Do we need an input of energy to unwind the double helix?", is A) Yes, due to hydrogen bonding.