Telomeres are repeat nucleotide sequences (TTAGGG) and protein on the ends of chromosomes that prevent degradation and end–end ligation. They act as natural caps and prevent chromosomes from fusing together. Telomere length is progressively reduced with each cell division until the cell becomes senescent.
What are the ends of eukaryotic chromosomes called?
The ends of eukaryotic chromosomes are called telomeres.
What is a repetitive DNA at the end of a eukaryotic chromosome?
Repetitive regions at the very ends of chromosomes are called telomeres, and they’re found in a wide range of eukaryotic species, from human beings to unicellular protists. Telomeres act as caps that protect the internal regions of the chromosomes, and they’re worn down a small amount in each round of DNA replication.
What is so special about the ends of the eukaryotic chromosomes?
Telomeres are special regions, located on each end of the chromosome, that consist of repetitive sequences of base pairs. They are typically described as being like the plastic caps on the ends of shoelaces. This is because they protect the ends of chromosomes and keep them from sticking to other chromosomes.
Which answer best describes the role of telomerase in replicating the ends of linear chromosomes?
Which answer best describes the role of telomerase in replicating the ends of linear chromosomes? It catalyzes the lengthening of telomeres, compensating for the shortening that could occur during replication without telomerase activity. Telomere shortening puts a limit on the number of times a cell can divide.
What attaches DNA sequences at the ends of eukaryotic chromosomes?
The ends of linear chromosomes, called telomeres, protect genes from getting deleted as cells continue to divide. The telomerase enzyme attaches to the end of the chromosome; complementary bases to the RNA template are added on the 3′ end of the DNA strand.
What activity does telomerase use to replicate the ends of chromosomes?
In Summary: Telomeres
Telomerase, an enzyme with a built-in RNA template, extends the ends by copying the RNA template and extending one end of the chromosome. DNA polymerase can then extend the DNA using the primer. In this way, the ends of the chromosomes are protected.
What is the sequence composition of telomeres?
Telomeres are made up of repeated segments of DNA that consist of the sequence 5′-TTAGGG-3′ (in which T, A, and G are the bases thymine, adenine, and guanine, respectively). Some human cells contain as many as 1,500 to 2,000 repeats of this sequence at each end of each chromosome.
What are the 3 major steps in DNA replication?
How is DNA replicated? Replication occurs in three major steps: the opening of the double helix and separation of the DNA strands, the priming of the template strand, and the assembly of the new DNA segment. During separation, the two strands of the DNA double helix uncoil at a specific location called the origin.