OBJECTIVE LIFE SCIENCE
MOLECULAR BIOLOGY
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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telomeres
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telomerase
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Okazaki fragments
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primer
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Detailed explanation-1: -The ends of the linear chromosomes are known as telomeres: repetitive sequences that code for no particular gene. These telomeres protect the important genes from being deleted as cells divide and as DNA strands shorten during replication. In humans, a six base pair sequence, TTAGGG, is repeated 100 to 1000 times.
Detailed explanation-2: -Every time a cell? carries out DNA replication? the chromosomes are shortened by about 25-200 bases (A, C, G, or T) per replication. However, because the ends are protected by telomeres, the only part of the chromosome that is lost, is the telomere, and the DNA is left undamaged.
Detailed explanation-3: -Telomeric DNA consists of a tract of duplex tandem repeats terminating with a single-stranded 3’ overhang. In mammals, the telomeric repeat sequence 5’-TTAGGG-3’ is bound by complexes of proteins collectively termed shelterins (Palm and de Lange, 2008).