Nucleus Structure/ Easy / Step By Step / For High Class Students Of Biology скачать в хорошем качестве

Nucleus Structure/ Easy / Step By Step / For High Class Students Of Biology

The nucleus is the control center of the cell, responsible for regulating all cellular activities such as growth, metabolism, protein synthesis, and cell division. It contains the genetic material (DNA), which determines the characteristics and functions of the organism. --- 1. Nuclear Envelope (Nuclear Membrane) The nuclear envelope is a double-layered membrane that surrounds the nucleus and separates it from the cytoplasm. The outer membrane is continuous with the endoplasmic reticulum and may have ribosomes attached. The inner membrane lines the inside of the nucleus and maintains its shape. The two membranes are separated by a perinuclear space. The envelope contains nuclear pores, which allow the selective exchange of materials like RNA, proteins, and ions between the nucleus and cytoplasm. --- 2. Nuclear Pores Nuclear pores are large protein channels present on the nuclear envelope. They control the movement of substances in and out of the nucleus. mRNA, tRNA, and ribosomal subunits pass through these pores. They help maintain communication between the nucleus and cytoplasm. --- 3. Nucleoplasm (Nuclear Sap) The nucleoplasm, also called karyolymph or nuclear sap, is a gel-like matrix inside the nucleus. It supports the chromatin fibers and nucleolus. It contains nucleotides, enzymes, and ions required for DNA and RNA synthesis. It serves as a medium for the transportation of molecules within the nucleus. --- 4. Chromatin Material The chromatin is a network of thread-like structures present in the nucleoplasm. It is composed of DNA and histone proteins. There are two types: Euchromatin: Lightly stained, less condensed, and transcriptionally active (involved in gene expression). Heterochromatin: Darkly stained, tightly packed, and transcriptionally inactive (non-coding or silent DNA regions). During cell division, chromatin condenses to form chromosomes, which carry genes, the units of heredity. --- 5. Nucleolus The nucleolus is a dense, round body found inside the nucleus. It is not membrane-bound. It is composed of RNA and proteins. Its main function is to synthesize ribosomal RNA (rRNA) and assemble ribosomal subunits. Cells with high protein synthesis activity (like liver or nerve cells) have prominent nucleoli. --- 6. Nuclear Matrix The nuclear matrix is a fibrous network that provides structural support to the nucleus. It anchors the chromatin and nucleolus. It helps organize DNA replication and RNA transcription processes. --- 7. Genetic Material (DNA) Inside the chromatin, DNA carries genetic instructions for building proteins and regulating cellular functions. It controls inheritance, cell behavior, and metabolic pathways. Genes are specific DNA segments coding for particular traits. --- Functions of Nucleus 1. Control Center: Regulates all cellular activities. 2. Genetic Storage: Stores hereditary information in the form of DNA. 3. Protein Synthesis: Directs synthesis of proteins via mRNA. 4. Cell Division: Plays an essential role in mitosis and meiosis. 5. RNA Formation: Nucleolus synthesizes rRNA and forms ribosomes. #CellNucleus #NucleusStructure #NuclearEnvelope #Chromatin #Euchromatin #Heterochromatin #Nucleolus #NuclearSap #CellBiology #BiologyDrawing #HumanCell #StudyBiology #Microscopy #ExamPrepBiology #BiologyEducation