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Question
Explain the process of DNA replication with the help of a schematic diagram.
Solution
DNA Replication
DNA replication is the phenomenon in which a duplicate copy of DNA is synthesised.
The steps involved in the process of DNA replication are as follows:
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DNA replication occurs in S-phase of the cell cycle.
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Enzyme involved: DNA polymerase (DNA dependent DNA polymerase)
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Replication requires energy.
Source of energy −Deoxyribonucleoside triphosphates (DNTPs) -
DNTPs have dual purposes: act as substrates as well as provide energy
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Replication initiates at specific regions in DNA called the origin of replication.
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DNA polymerase polymerises a large number of nucleotides in a very short time.
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During the course of replication, two parent strands do not completely open, but a small opening forms in which replication occurs. This small opening forms a replication fork.
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DNA polymerase can polymerise only in one direction, i.e., 5'→3'.
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Therefore, replication occurs smoothly in 3'to 5'end of DNA (continuous replication, but occurs discontinuously in 5' to 3'end).
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The discontinuous fragments so formed are joined by DNA ligase.
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