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Multiple Choice
How does telomerase prevent linear chromosomes from shortening during replication?
A
By initiating the replication of the entire chromosome
B
By adding repetitive nucleotide sequences to the ends of chromosomes
C
By facilitating the binding of histones to chromosome ends
D
By removing damaged DNA segments from the chromosome ends
Verified step by step guidance
1
Understand that during DNA replication, the ends of linear chromosomes, known as telomeres, tend to shorten because DNA polymerase cannot fully replicate the 3' ends of the lagging strand.
Recognize that telomerase is an enzyme that helps maintain the length of telomeres, thus preventing the loss of important genetic information over successive cell divisions.
Telomerase contains an RNA template that it uses to extend the 3' end of the telomere by adding repetitive nucleotide sequences, typically rich in guanine, to the ends of chromosomes.
This extension provides a template for the lagging strand synthesis, allowing DNA polymerase to complete the replication of the chromosome ends without losing important DNA sequences.
By adding these repetitive sequences, telomerase effectively prevents the progressive shortening of chromosomes, which is crucial for maintaining genomic stability and cellular lifespan.