Quick Answer: What activity does telomerase use to replicate the ends of chromosomes?

How do telomeres replicate?

Telomerase is an RNA-dependent DNA polymerase, meaning an enzyme that can make DNA using RNA as a template. … When the overhang is long enough, a matching strand can be made by the normal DNA replication machinery (that is, using an RNA primer and DNA polymerase), producing double-stranded DNA.

What kind of activity does telomerase have?

Telomerase is the enzyme responsible for maintenance of the length of telomeres by addition of guanine-rich repetitive sequences. Telomerase activity is exhibited in gametes and stem and tumor cells.

How does telomerase solve end replication problem?

Telomerase is a reverse transcriptase that adds telomeric repeats to the 3′ ends of each chromosome (3). In doing so, telomerase makes up for the shortcomings of semiconservative DNA replication, which cannot complete the synthesis of chromosome ends.

What are telomeres in DNA replication?

Telomeres are the physical ends of eukaryotic chromosomes. They protect chromosome ends from DNA degradation, recombination, and DNA end fusions, and they are important for nuclear architecture. Telomeres provide a mechanism for their replication by semiconservative DNA replication and length maintenance by telomerase.

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Does telomerase have reverse transcriptase activity?

Telomerase is the enzyme required for the addition of telomeric repeats to the ends of linear chromosomes. It consists of a reverse transcriptase, TERT, that carries its own template in the form of an RNA moiety, TER. In vitro this complex can add telomeric repeats to artificial substrates.

What is the normal role of telomerase?

Telomerase is a large ribonucleoprotein complex responsible for progressive synthesis of telomeric DNA repeats (TTAGGG) at the 3′ ends of linear chromosomes, thereby reversing the loss of DNA from each round of replication.

What is the role of telomerase in cells?

Telomerase is a cellular reverse transcriptase that helps to provide genomic stability in highly proliferative normal, immortal, and tumor cells by maintaining the integrity of the chromosome ends, the telomeres. The activity of telomerase is associated with the majority of malignant human cancers.

How telomeres solve the end protection problem?

Telomeres solve this end-protection problem by repressing all forms of DDR signaling and DSB repair. The telomeric DNA, maintained by telomerase, binds a six-subunit protein complex, termed shelterin, that protects chromosome ends.

What is the end replication problem why in the absence of telomerase do the ends of linear chromosomes get progressively shorter each time the DNA is replicated?

There are ends at the DNA in eukaryotes, unlike the prokaryotic DNA that become shorter after each replication cycle. This is known as the end replication problem. It occurs because the lagging strands of the DNA do not get synthesized for the end of the DNA after the removal of RNA primers.

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Why does the presence of telomeres protect the ends of linear chromosomes?

Why does the presence of telomeres protect the genetic information of linear chromosomes from loss? The telomeres represent large buffer zones of DNA sequence that do not code for biomolecules. Loss of these sequences is tolerated.