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प्रश्न
Explain the process of DNA replication with the help of a schematic diagram.
उत्तर
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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संबंधित प्रश्न
Describe the experiment that helped demonstrate the semi-conservative mode of DNA replication.
Draw a diagrammatic sketch of a portion of DNA segment to support your answer.
How was a heavy isotope of nitrogen used to provide experimental evidence to semi-conservative mode of DNA-replication ?
Which of the following is correct for Watson and Crick’s model of DNA. It is duplex with ______.
DNA replication is ______.
If Meselson and Stahl's experiment is continued for four generations in bacteria, the ratio of `15_N/15_N:15_N/14_N:14_N/14_N` containing DNA in the fourth generation would be ______.
Okazaki fragments are seen during ______.
DNA replication takes place at ______ phase of the cell.
In order to form a dinucleotide during DNA synthesis which functional group at 3' must be free?
The DNA molecules of the same size were extracted from E. coli and Plasmodium vivax. It was discovered that both the DNA molecules had one target site each for the restriction enzyme Hind II. After being digested with Hind II, the DNA fragments were subjected to gel electrophoresis.
With reference to the diagram given below, identify the lanes that represent the DNA fragments of E. coli and Plasmodium vivax respectively. Justify your answer with a reason for each.
