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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the enzyme telomerase is readily destroyed by the environment, resulting in cell death.
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DNA replication is subject to errors that cause cell death.
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Okazaki fragments disrupt protein synthesis, resulting in cell death.
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the removal of the RNA primer following DNA replication leads to a shortening of the chromosome and eventual cell death
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Detailed explanation-1: -This is caused by the fact that in the course of replication on such telomeres, daughter chromosomes lose the 3’ overhang which was present in the parent chromosome and in the absence of telomerase this will accordingly result in their shortening.
Detailed explanation-2: -RNA primers are key to initiating DNA synthesis. They provide the initiation sequence necessary for DNA polymerase to synthesize new strands. The RNA primer is introduced at the template DNA site by primase enzyme on both the leading and lagging strands.
Detailed explanation-3: -The telomere acts as a buffer to ensure the important genetic information coded for on the chromosome is completely copied for each new cell and protected from damage. Over time, this results in fewer and fewer DNA repeats making up the telomeres after each cell division i.e. gradually the telomeres shorten.
Detailed explanation-4: -At each cell division, the telomeres shorten because of the incomplete replication of the linear DNA molecules by the conventional DNA polymerases. This is called the end replication problem [6]. This is specifically due to the resection and fill-in reaction during the synthesis of the telomere leading-strand [7, 8].