DNA in the cell nucleus is present as chromatin in a tight complex with histones and other proteins. This complex is central to the spatial organization of the DNA strand by balancing the negative charges of the phosphate backbone and is also crucial for gene regulation.
Is chromatin found in resting cells?
Chromatin is the name for the diffuse granular mass of DNA found in interphase cells. Heterochromatin is less abundant, relative to euchromatin, in the large nuclei of active cells than in the small nuclei of resting cells, such as small lymphocytes.
Why chromatin is found only in eukaryotes?
Interestingly, chromatin not only serves as a way to condense DNA within the cellular nucleus, but also as a way to control how that DNA is used. In particular, within eukaryotes, specific genes are not expressed unless they can be accessed by RNA polymerase and proteins known as transcription factors.
Is chromatin found in prokaryotic or eukaryotic cells?
In eukaryotic cells, chromatin consists of all the DNA within the nucleus and its associated proteins, called histones.
|Eukaryotic Chromosome||Prokaryotic Chromosome|
|Location||Nucleus||Nucleoid (region in cytoplasm)|
What is the difference between DNA and chromatin?
The DNA is packaged by special proteins called histones to form chromatin. The chromatin further condenses to form chromosomes.
|Difference between Chromosomes and Chromatin|
|Composed of nucleosomes||They are condensed chromatin fibers|
How many genes are on a chromosome?
Identifying genes on each chromosome is an active area of genetic research. Because researchers use different approaches to predict the number of genes on each chromosome, the estimated number of genes varies. Chromosome 1 likely contains 2,000 to 2,100 genes that provide instructions for making proteins.