THE MOLECULAR BASIS OF INHERITANCE
DNA REPLICATION
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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is a short strand of RNA added to the 5´ end of the template strand.
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is needed only once on a leading strand.
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remains on the DNA after replication.
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is added to only one of the two template strands.
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Detailed explanation-1: -For the leading strand, a special primer is needed only at the start of replication: once a replication fork is established, the DNA polymerase is continuously presented with a base-paired chain end on which to add new nucleotides.
Detailed explanation-2: -Only one primer is required for the initiation and propagation of leading strand synthesis.
Detailed explanation-3: -Answer and Explanation: During DNA replication, the leading strand is synthesized in a continuous manner and only needs one primer to initiate replication. In contrast, the lagging strand is synthesized in a discontinuous manner by forming short okazaki fragements.
Detailed explanation-4: -DNA Repair Enzymes: Cell, Molecular, and Chemical Biology Due to the semidiscontinuous nature of DNA replication, primase activity is not only essential during initiation but also to continuously prime Okazaki fragment synthesis on the lagging strand.
Detailed explanation-5: -During replication, the leading strand is synthesized continuously while the lagging strand is synthesized in the form of Okazaki fragments. The lagging strand has many RNA primers while the leading strand has a single RNA primer. These RNA primers are removed by DNA polymerase I and replaced by DNA fragments.