Question

When double-stranded DNA is heated to 95°C, the bonds between complementary base pairs break to produce single-stranded DNA. Considering this observation, is the strand separation step required for replication of the Double Helix an endergonic or exergonic reaction? Why?

a.Endergonic. Energy is released.
b.Exergonic. An input of energy is required.
c.Exergonic. The reaction is spontaneous.
d.Endergonic. An input of energy is required

Answer 1

The separation of DNA strands for replication is an endergonic reaction because it requires an input of energy, notably from ATP, for enzymes like helicase and topoisomerase to perform their functions in strand separation and DNA supercoiling management. Correct option is d)

Step-by-step explanation:

The separation of DNA strands during replication is an energy-requiring process. Therefore, the correct answer to the question is d. Endergonic. An input of energy is required. During replication, enzymes such as helicase unwind the DNA at the origin of replication, which requires energy in the form of ATP. Furthermore, topoisomerase breaks and reforms the DNA's phosphate backbone ahead of the replication fork to relieve supercoiling pressure and requires energy as well. Additionally, single-strand binding proteins stabilize the unwound DNA to prevent the double helix from re-forming spontaneously. In summary, the energy input required for DNA strand separation during replication characterizes it as an endergonic reaction.