Question

what does Endoreduplicated Chromosome means???​

Answer 1

Explanation:

Nuclear polyploidization occurs widely in metabolically active tissues of plants and animals, and the most common method by which it takes place is through endoreduplication (Brodsky and Uryvaeva, 1977; D'Amato, 1984). During this process, cells amplify their genome without chromatin condensation, segregation or cytokinesis, resulting in what appear to be multiple, uniform copies of the nuclear DNA. This process has been quantified in plants and animals (Bhatnagar and Sawhney, 1981; Kowles and Phillips, 1988), but its physiological significance is poorly understood. Endoreduplication could provide a mechanism to increase the availability of DNA templates and thus increase gene expression. Transcriptional and translational activities increase proportionately with each doubling of the genome, so the metabolic activity of a highly polyploid cell could be functionally equivalent to that of many diploid cells (D'Amato, 1984). It is also possible that endoreduplication maintains an optimum ratio between cell and nuclear size (Cavalier‐Smith, 1985). Typically, cells that have undergone endoreduplication are larger than comparable cells that have not. Being bigger and having a larger number of organelles (mitochondria and plastids) to service would potentially require greater transcription capacity. It was suggested that large cells have the capacity to increase their volume faster than smaller cells, and in the case of rapidly growing fruits and seeds, this could be advantageous (Grime and Mowforth, 1982). Because endoreduplication occurs frequently in seed storage tissues, such as cotyledons and endosperms, it has also been suggested that this process could provide a mechanism for storing nucleotides or nitrogen for the embryo. However, there is little experimental evidence showing that nucleotides are recycled, and this would be a very energy‐expensive way to store nitrogen. Consequently, the notion remains that endoreduplication more than likely occurs to provide higher than normal levels of gene expression when the constraints of time and space require it.

Answer 2

Explanation:

Abstract. Endoreduplication is a form of nuclear polyploidization that results in multiple, uniform copies of chromosomes. This process is common in plants and animals, especially in tissues with high metabolic activity, and it generally occurs in cells that are terminally differentiated.