chromatin
/'kroumətin/
Học thuậtThân thiện
Definition
- Noun:
- The readily stainable substance of a cell nucleus: Chromatin is the complex of DNA, RNA, and various proteins (such as histones) that makes up the contents of a cell nucleus. It is the material from which chromosomes are formed.
Usage
- Chromatin is a fundamental biological term used in cell biology and genetics to describe the structural form of genetic material within the nucleus of a eukaryotic cell when the cell is not dividing.
- It is the default state of packaged DNA, which undergoes further condensation to form visible chromosomes during cell division (mitosis and meiosis).
Examples
- Noun:
- Under a microscope, the chromatin appears as a granular, thread-like mass within the nucleus.
- The primary function of chromatin is to efficiently package long DNA molecules into a compact, dense structure to fit inside the nucleus.
- Changes in chromatin structure can regulate gene expression without altering the DNA sequence itself.
Advanced Usage
- "Chromatin remodeling": Refers to the dynamic modification of chromatin architecture to allow access of condensed genomic DNA to the regulatory transcription machinery proteins, and thereby control gene expression.
- Chromatin remodeling complexes are essential for activating or repressing genes.
- "Chromatin immunoprecipitation (ChIP)": A laboratory technique used to investigate the interaction between proteins and DNA in the cell, specifically to determine where specific proteins bind to the genome.
- Researchers used chromatin immunoprecipitation to map the binding sites of a transcription factor.
Variants and Related Words
- Chromosomal (adj): Pertaining to chromosomes.
- The chromosomal abnormalities were identified.
- Euchromatin (n): A lightly packed form of chromatin that is rich in gene concentration and is often under active transcription.
- Euchromatin is less condensed and genetically active.
- Heterochromatin (n): A tightly packed form of chromatin that is generally transcriptionally inactive.
- Heterochromatin is found in regions of the chromosome such as centromeres and telomeres.
Synonyms
- Nuclear material: A general term for the substance within the nucleus.
- Nucleoprotein complex: Describes the combination of nucleic acids and proteins that constitutes chromatin.
Related Terms and Phrases
- Chromatin fiber: The basic structural unit of chromatin, consisting of DNA wound around histone proteins.
- The nucleosome is the fundamental repeating unit of the chromatin fiber.
- Chromatin condensation: The process by which chromatin becomes more compact, especially during prophase of mitosis.
- Chromatin condensation is a critical step in preparing for cell division.
Noun
- the readily stainable substance of a cell nucleus consisting of DNA and RNA and various proteins; during mitotic division it condenses into chromosomes