chromatin

Mitosis

...ial ( DNA ), which normally exists in the form of chromatin condenses into a highly ordered structure called a chromosome . Since the genetic material has been duplicated, there are two identical copies of each chromosome in the cell. Identical chromosomes (called sister chromosomes) are attached to each o...

Spermatid

...ermatid elongation. The resultant tightly packed chromatin is transcriptionally inactive....

Semen

...nc serves to help to stabilize the DNA containing chromatin in the sperm cells. A zinc deficiency may result in lowered fertility because of increased sperm fragility. Zinc deficiency can also adversely affect spermatogenesis . The simple sugar fructose is the main energy source of sperm cells, which ...

Prophase

...ial ( DNA ), which normally exists in the form of chromatin , condenses into a highly ordered structure called a chromosome . Since the genetic material has been duplicated, there are two identical copies of each chromosome in the cell. Identical chromosomes (called sister chromosomes) are attached to each ...

Nucleosome

... found in the cell nucleus in eukaryotes . All chromatin (except for that packaged in the sperm nucleus)...his structure. Beyond 30 nm fiber the structure of chromatin is poorly understood, but it is classically suggested that the 30 nm fiber is arranged into loops al...

Mitosis

...ial ( DNA ), which normally exists in the form of chromatin condenses into a highly ordered structure called a chromosome . Since the genetic material has been duplicated, there are two identical copies of each chromosome in the cell. Identical chromosomes (called sister chromosomes) are attached to each o...

Lyon hypothesis

...embryogenesis . X-inactivation leads to clumped chromatin termed Barr bodies , which are generally considered inert. This formation of Barr bodies is called Lyonization . In humans the X chromosome that is inactivated is determined by chance. In marsupials , however, the paternal X chromosome is always...

Histone

...n biology, histones are the chief proteins of chromatin . They act as spools around which DNA winds and they play a role in gene regulation .Histones are found in the nuclei of eukaryotic cells . Bacteria do not have histones, but histones are found in certain Archaea, namely Euryarchaea. These a...

Epigenetics

... in DNA methylation , as well as difference in chromatin structure. Another possibility involves the genomes of cytoplasmic elements ( chloroplasts and mitochondria ). Other mechanisms have also been proposed. See epigenetic inheritance for a more detailed discussion. The epigenome is the overall e...

Disulfide bond

...med within and between protamines in the sperm chromatin of many mammalian species. In hair Hair is a biological polymer, with over 90% of its dry weight made of proteins called keratins . Under normal conditions, human hair contains around 10% water, which modifies its mechanical properties cons...

Chromosome

.... 1), and where this composite material is called chromatin . During mitosis (cell division), the chromosome...igin of replication. Chromatin Two types of chromatin can be distinguished: Euchromatin , which consists of DNA that is active, e.g., expressed as pro...

Chromatin

...le-stranded DNA. The major proteins involved in chromatin are histone proteins . In a eukaryotic cell...ound compacted in chromatin. DNA is packaged into chromatin both to constrain the size of the molecule and to allow the cell to control expression of the chro...

Cell nucleus

...he DNA is present as a DNA-protein complex called chromatin . The DNA is present as a number of discrete units known as chromosomes . There are two types of chromatin: euchromatin and heterochromatin. Euchromatin is the least compact form of DNA, and the regions of DNA which constitute euchromatin contain g...

Apoptosis

...ed, also, that while the previous stage of initial chromatin condensation has been observed in nonapoptotic for...exis ). The nucleus breaks into several discrete chromatin bodies or nucleosomal units due to the degradation of DNA [4] . Plasma membrane blebbings....