Medical Genetics - V. M. Zaporozhan 2005

Introduction to Medical Genetics
Cytological Foundations of Heredity
Structure and Functions of the Nucleus and Chromosomes - Structure of the Nucleus

The Nucleus contains the following structural components: 1) the nuclear envelope; 2) the nuclear sap (karyoplasm, nucleoplasm); 3) the nuclear protein matrix; 4) Chromosomes; 5) nucleoli.

The nuclear envelope consists of two membranes separated by the perinuclear space. The outer membrane is continuous with The Endoplasmic reticulum. The inner membrane is lined on its inner surface by a network of Fibrillar Proteins known as the nuclear lamina. The nuclear envelope is perforated by pores that mediate molecular exchange between the nucleus and the Cytoplasm.

The nuclear sap represents the internal content and microenvironment of the nucleus. It contains Enzymes, NUCLEOTIDES, RNA, and ions in the form of a true or colloidal solution. The nuclear sap is permeated by a network of fibrillar proteins referred to as the nuclear protein matrix. Chromosomes, as well as various Structure/178.html">Protein Complexes possessing enzymatic and regulatory activities, are attached to the nuclear protein matrix and nuclear lamina.

Chromosomes are permanent Structural components of the nucleus that house genes and store hereditary information.

Nucleoli are formed at specific chromosomal regions known as nucleolar organizers. The nucleolar organizer contains genes that encode ribosomal RNA. Here, rRNA synthesis takes place along with the assembly of ribosomal subunits.



Last update: 11/08/2026

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