BIOLOGY
STRUCTURE OF NUCLEIC ACIDS
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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to replace RNA primers with DNA during replication
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to join Okizaki fragments during replication
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to add RNA nucleotides during transcription
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to add the poly-A tail to pre-mRNA
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Detailed explanation-1: -The Okazaki fragments should be attached into one continuous strand once replication occurs. This is achieved by the DNA ligase that seals the sugar-phosphate backbone of the Okazaki fragments. This enables the replication of two continuous, identical daughter DNA strands.
Detailed explanation-2: -DNA ligase I Okazaki fragments that are not ligated could cause double-strand-breaks, which cleaves the DNA. Since only a small number of double-strand breaks are tolerated, and only a small number can be repaired, enough ligation failures could be lethal to the cell.
Detailed explanation-3: -DNA ligases play an essential role in maintaining genomic integrity by joining breaks in the phosphodiester backbone of DNA that occur during replication and recombination, and as a consequence of DNA damage and its repair.
Detailed explanation-4: -These small pieces of newly synthesized DNA (called Okazaki fragments after their discoverer) are joined by the action of DNA ligase, forming an intact new DNA strand.