OBJECTIVE LIFE SCIENCE
MOLECULAR BIOLOGY
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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What is the basis for the difference in how the leading and lagging strands of DNA molecules are synthesized?
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DNA polymerase can join new nucleotides to the 3’ end of the preexisting strand.
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Helicases and single-strand binding proteins work at the 5’ end.
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The origins of replication occur only at the 5’ end.
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DNA ligase works only in the 3’ to 5’ direction
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Explanation:
Detailed explanation-1: -On the leading strand, DNA synthesis occurs continuously. On the lagging strand, DNA synthesis restarts many times as the helix unwinds, resulting in many short fragments called “Okazaki fragments.” DNA ligase joins the Okazaki fragments together into a single DNA molecule.
Detailed explanation-2: -Due to the antiparallel orientation of the two chromosomal DNA strands, one strand (leading strand) is replicated in a mostly processive manner, while the other (lagging strand) is synthesized in short sections called Okazaki fragments.
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