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In this example, the length of the chromosome has increased slightly during DNA synthesis; normally, telomeres are maintained at a constant length by complex regulatory mechanisms. In some cells, telomerase is absent and telomeres gradually shorten with each cell division. [1]
A chromosome consists of a long strand of DNA containing many genes. A human chromosome can have up to 500 million base pairs of DNA with thousands of genes." See also
Telomere: Used to maintain chromosomal integrity by capping off the ends of the linear chromosomes. This region is a microsatellite , but its function is more specific than a simple tandem repeat. Throughout the eukaryotic kingdom, the overall structure of chromosome ends is conserved and is characterized by the telomeric tract - a series of ...
A telomere (/ ˈ t ɛ l ə m ɪər, ˈ t iː l ə-/; from Ancient Greek τέλος (télos) 'end' and μέρος (méros) 'part') is a region of repetitive nucleotide sequences associated with specialized proteins at the ends of linear chromosomes (see Sequences). Telomeres are a widespread genetic feature most commonly found in eukaryotes.
Telomerase can bind the first few nucleotides of the template to the last telomere sequence on the chromosome, add a new telomere repeat (5'-GGTTAG-3') sequence, let go, realign the new 3'-end of telomere to the template, and repeat the process. Telomerase reverses telomere shortening.
This problem makes eukaryotic cells unable to copy the last few bases on the 3' end of the template DNA strand, leading to chromosome—and, therefore, telomere—shortening every S phase. [2] Measurements of telomere lengths across cell types at various ages suggest that this gradual chromosome shortening results in a gradual reduction in ...
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Telomeres extend the 3' end of the parental chromosome beyond the 5' end of the daughter strand. This single-stranded DNA structure can act as an origin of replication that recruits telomerase. Telomerase is a specialized DNA polymerase that consists of multiple protein subunits and an RNA component.