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Simple and concise definition: Chromatin is a macromolecular complex of a DNA macromolecule and protein macromolecules (and RNA). The proteins package and arrange the DNA and control its functions within the cell nucleus. A biochemists' operational definition: Chromatin is the DNA/protein/RNA complex extracted from eukaryotic lysed interphase ...
Chromatin contains the vast majority of the DNA in an organism, but a small amount inherited maternally can be found in the mitochondria. It is present in most cells, with a few exceptions, for example, red blood cells. Histones are responsible for the first and most basic unit of chromosome organization, the nucleosome.
Chromatin refers to the combination of DNA and proteins that make up chromosomes. When a cell is not dividing, chromosomes exist as loosely packed chromatin mesh. [3] The genome of an organism (encoded by the genomic DNA) is the (biological) information of heredity which is passed from one generation of organism to the next.
Packaging of nucleosomes into higher order chromatin structures involves the use of loops and coils. In eukaryotes, such as humans, roughly 3.2 billion nucleotides are spread out over 23 different chromosomes (males have both an X chromosome and a Y chromosome instead of a pair of X chromosomes as seen in females). Each chromosome consists ...
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.
The solenoid structure's most obvious function is to help package the DNA so that it is small enough to fit into the nucleus. This is a big task as the nucleus of a mammalian cell has a diameter of approximately 6 μm, whilst the DNA in one human cell would stretch to just over 2 metres long if it were unwound. [6]
Chromatin diminution (founding father: Theodor Boveri). In this process, found in some copepods and roundworms such as Ascaris suum , portions of the chromosomes are cast away in particular cells. This process is a carefully organised genome rearrangement where new telomeres are constructed and certain heterochromatin regions are lost.
A chromatid (Greek khrÅmat-'color' + -id) is one half of a duplicated chromosome.Before replication, one chromosome is composed of one DNA molecule. In replication, the DNA molecule is copied, and the two molecules are known as chromatids. [1]