NUCLEOSOMES Meaning and
Definition
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Nucleosomes are basic structural units of chromatin, which is the complex packing arrangement of DNA and proteins within the nucleus of eukaryotic cells. Consisting of a core particle and linker DNA, nucleosomes help to organize and compact DNA in such a way that it can fit into the limited space of the nucleus.
Each nucleosome core particle is composed of approximately 147 base pairs of DNA wrapped around a cylindrical structure called a histone octamer. The histone octamer consists of two copies each of histones H2A, H2B, H3, and H4, forming a protein core with a positively charged surface to which the negatively charged DNA can bind.
Linker DNA is the spacer region between nucleosomes, which is defined as approximately 20-60 base pairs in length. It connects adjacent nucleosome core particles and provides flexibility in chromatin structure. Additional proteins known as histone H1 or H5 may bind to linker DNA, further stabilizing the structure and promoting the formation of compact chromatin fibers.
Nucleosomes play vital roles in regulating DNA accessibility and gene expression by either tightly compacting the DNA to restrict access or through dynamic rearrangements to allow access for transcription factors and other DNA-binding proteins. The modification of histone proteins, such as acetylation, methylation, or phosphorylation, can also influence nucleosome structure and function, thereby affecting gene expression. Overall, nucleosomes contribute to the organization, stability, and modulation of gene activity within the nucleus of eukaryotic cells.
Common Misspellings for NUCLEOSOMES
- bucleosomes
- mucleosomes
- jucleosomes
- hucleosomes
- nycleosomes
- nhcleosomes
- njcleosomes
- nicleosomes
- n8cleosomes
- n7cleosomes
- nuxleosomes
- nuvleosomes
- nufleosomes
- nudleosomes
- nuckeosomes
- nucpeosomes
- nucoeosomes
- nuclwosomes
- nuclsosomes
- nucldosomes
Etymology of NUCLEOSOMES
The word "nucleosome" is derived from two components: "nucleo-" and "-some".
1. "Nucleo-" is derived from the Latin word "nucleus", which means "kernel" or "nucleus of a cell". This term was used to refer to the essential part of a structure.
2. "-some" is a suffix derived from the Greek word "soma", which means "body". It is commonly used to denote a collection, group, or body of something.
Therefore, when combined, "nucleosome" refers to the basic repeating unit of chromatin, which is the complex of DNA and proteins that make up chromosomes in eukaryotic cells. The term reflects the association of DNA (nucleus) and proteins (body) within this structure.
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