"Structure of chromosome with diagram"

Introduction:

The components of a cell's nucleus called chromosomes house hereditary information. During cell division, they are crucial for the transfer of genetic material from one generation to the next. DNA, proteins, and other components make up a chromosome's makeup. The genetic code, which is arranged into genes that code for proteins and other useful compounds, is found in the DNA molecule. The DNA is connected to proteins and other substances that help control its expression and guarantee accurate transfer during cell reproduction.

Physical Structure of Chromosomes:

A) Pellicle: The thin covering around the chromosomes is called the pellicle. It protects the inner parts of the chromosomes.

B) Matrix: The thick jelly-like substance inside the pellicle is called a matrix.

C) Chromatids and Chlomonemata: The two coiled filaments of similar shape and nature along the length of the chromosomes at the metaphase stage are called chromatids (each chromatid is called genonema). It is scaly and vividly pigmented. Each of the two filaments spirally arranged along the length of the chromatid is called a chromonema (singular). It is not as patchy as spring and is not obvious when dyed. It cannot be separated under any circumstances. The chromosome fibers are coiled around each other.

D) Chromomeres: Chromonemata contain numerous granule-shaped objects along their entire length. These grains are called Chromamere. Chromomeres appear as the chromonemata are coiled.

E) Centromere: Each chromosome has a round, compact region. Its name is centromere. The centromere is called the central nucleus. And the part extending on either side is called the arm of the chromosome. Centromere participates in chromosome movement, attachment of chromosomes to the cytoplasm, and chromosome formation.

F) Secondary Constriction: Apart from the centromere, another constriction occurs in one or both arms of the chromosome, it is called secondary constriction. Secondary contractile that participate in nucleolus assembly is called nucleolar organizers. Convoluted chromosomes are called nucleolar chromosomes. Each nucleus contains two such chromosomes.

G) Satellite: The peripheral chromosomal bulge (bulging) portion of the secondary groove chromosome is called a satellite. This segment is attached to the chromosome body by a circular chromatin formula. Chromosomes containing satellites are called sat chromosomes.

H) Telomere: The special ends of the two arms of the chromosomes are called telomeres. The ends are correctly polarized and tangential and do not join the broken segment of another chromosome.

Chemical composition of chromosomes:

The chemical structure of chromosomes is quite complex. It is composed of (a) two types of nucleic acids, namely- DNA and RNA, and (b) two types of proteins, namely- histones and chromosomes. DNA and histone amounts in chromosomes are 35% and 55% respectively. 

Functions of Chromosomes:

1) Contains DNA or gene molecules.

2) Synthesizes proteins through RNA.

3) Changes in the number and structure of chromosomes due to various reasons are used as key factors in evolution.

Conclusion:

Chromosomes are woven-like organelles that house DNA, which is the hereditary material. Every cell in the human body contains them, and they are crucial in defining a person's features and characteristics. Cell division, growth, and development are all carried out by chromosomes, which are found in pairs, one duplicate of which is passed from each parent.Our knowledge of genetics and the fundamental causes of inherited illnesses has greatly improved as a result of chromosome research. As an illustration, the identification of genomic anomalies has shed light on the genetics underlying disorders like Down syndrome, Turner syndrome, and Klinefelter syndrome.