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The largest regions on each chromosome are the short arm p and the long arm q, separated by a narrow region near the center called the centromere. [1] Other specific regions have also been defined, some of which are similarly found on every chromosome, while others are only present in certain chromosomes. Named regions include: Arms (p and q ...
Chromosome replication proceeds in three major stages: initiation, elongation and termination. The initiation stage starts with the ordered assembly of "initiator" proteins at the origin region of the chromosome, called oriC. These assembly stages are regulated to ensure that chromosome replication occurs only once in each cell cycle.
An increased propensity to separate the DNA strands (the so-called 'stress induced duplex destabilization' potential, SIDD) can serve the formation of secondary structures such as cruciforms or slippage structures, which are recognizable features for a number of enzymes (DNAses, topoisomerases, poly(ADP-ribosyl) polymerases and enzymes of the ...
Some sequences are required for a properly functioning chromosome: Centromere: Used during cell division as the attachment point for the spindle fibers. 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.
But this is only present when the cell divides. Researchers have now been able to model the structure of chromosomes when they are active. This is extremely important because the way that DNA folds up in chromosome structures is linked to the way DNA is used. Scientists have been able to develop the 3D structures of chromosomes in a single cell.
In biology, the chromosome scaffold is the backbone that supports the structure of the chromosomes. It is composed of a group of non-histone proteins that are essential in the structure and maintenance of eukaryotic chromosomes throughout the cell cycle. These scaffold proteins are responsible for the condensation of chromatin during mitosis. [1]
The physical role of the centromere is to act as the site of assembly of the kinetochores – a highly complex multiprotein structure that is responsible for the actual events of chromosome segregation – i.e. binding microtubules and signaling to the cell cycle machinery when all chromosomes have adopted correct attachments to the spindle, so ...
The average cell will divide between 50 and 70 times before cell death. As the cell divides the telomeres on the end of the chromosome get smaller. The Hayflick limit is the theoretical limit to the number of times a cell may divide until the telomere becomes so short that division is inhibited and the cell enters senescence.