Chromatin, types and functions of chromatin
- 1. CHROMATIN, ITS TYPES AND FUNCTIONS Presented by: B.Rajeshwari Pharm D
- 2. CHROMATIN Chromatin is a mass of genetic material composed of DNA & Proteins that condenses to form chromosomes during eukaryotic cell division. Chromatin is located in nucleus of the cells. CHROMATIN FUNCTION: To compress the DNA into a compact unit( Less voluminous) and can fit with in the nucleus. It consists of his tones and DNA.
- 3. Histones help to organize DNA into structures called Nucleosides. A Nucleosome consists of a DNA sequence of about 150 base pairs that is wrapped around set of 8 histones. The Functional unit of chromatin is nucleosome. nucleosome further folded to form a chromatin fibers. The chromatin fibers coiled and it condensed to form chromosomes. Chromatin is responsible for DNA replication, transcription, DNA repair, genetic recombination and cell division. TYPES OF CHROMATIN: Euchromatin Heterochromatin EUCHROMATIN: During interphase of the cell cycle, cell is not dividing but undergoes a period of growth, the chromatin is a less compact form is known as Euchromatin.
- 4. It allows DNA replication and DNA transcription. During transcription, DNA double helix, unwinds and opens to allowed genes coding for portions to be copied. It is needed for the cell to synthesize DNA, proteins and organelles for cell division. CHROMATIN MITOSIS:-- PROPHASE:--Chromatin fibers coiled into chromosomes. Each replicated chromosome consists of two chromatids joined at centromere region. METAPHASE:-- Chromatin becomes extremely condensed and chromosome gets aligned.
- 5. ANAPHASE: during anaphase, the paired chromosomes called sisterchromatids separates and are pulled by spindle microtubules to the opposite ends of the cells. TELOPHASE: Each new daughter chromosomes is separated into its own nucleus. Chromatin fibers uncoil and become less condensed to genetically identical daughter cells are produced. Each cell has the same number of chromosomes. These chromosomes continue to uncoil .
- 6. ANAPHASE:-- During Anaphase, the paired chromosomes separate and are pulled by spindles microtubules to the opposite ends of the cells. TELOPHASE:--- Each new daughter chromosome is separated into its own nucleus. Chromatin fibres uncoil and become less condensed to genetically identical daughter cells are produced.
- 7. CHROMATIN, CHROMOSME AND CHROMATID: •All these structures are composed of DNA and bound within the nucleus and each one is unique. CHROMATIN: It is composed of DNA and histones that are placed into thin fibers. These chromatin fibers are not condensed but can exist either in a compact form (heterochromatin) or a less compact form (euchromatin). •DNA replication, transcription and recombination
- 8. Occurring in euchromatin. During cell division, chromatin condenses to form chromosomes. CHROMOSOMES: They are single stranded groupings of condensed chromatin. During cell division, process of mitosis and meosis, chromosomes replicate to each new daughter cells receives the correct no. of chromosomes. A duplicated chromosome is a double stranded and has the ’X’ shape .
- 9. •strands are identical and connected at a central region called centromere. •CHROMATID: It is either of the two strands of replicated chromosome. Chromatids are connected by a centromere called sister chromatids. At the end of cell division, sister chromatids becoming daughter chromosomes in the newly formed daughter cells.
- 10. FLOW OF GENETIC INNFORMATION: •Cell inherent molecules energy And genetic information. •Genetic information is encoded in DNA. •DNA has the structure of double helix. •DNA is replicated before cell division. •Genetic information flows from DNA to RNA to Protein. •Cells express genetic information electively. •Chromosome structure changes during the cell cycle. •Chromosome number changes during the life cycle.
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