Types of Chromosome with Diagram

Introduction:

The word Chromosome is derived from the Greek words Chroma (color) and Soma (body)."Chromosomes are called chromosomes, which are located in the dividing nucleus of plant and animal cells, are rich in genes carrying the characteristic features of the organism, and are characterized by structure and function, which play a significant role in the functions of heredity, mutation, and variation, etc." Chromosome Organisms are heritably transmitted between offspring. In 1875, Strasburger discovered the first chromosome and in 1888, the scientist Valdeier (1888) first used the name chromosome.

A number of chromosomes: 

• The number of chromosomes is species-specific. As the number of chromosomes is half in two types of reproductive cells, sperm or egg, it is called gametic single number or haploid set. The collection of genes in the haploid set of chromosomes is called the genome.
• As the body cell has two haploid sets or two genomes, it is called the diploid set of chromosomes. Haploid The haploid set of chromosomes of male and female gametes combine to form the diploid number of chromosomes.
• The lowest number of haploid chromosomes is known to exist in roundworms. The haploid number of animals like flatworms, polychaetes, etc. is two (H=2). About 500 (2n) in amoeba.
• Chromosome number of some animals : Drosophila- 8; Kunobang- 22; Fly-12; Bees - 32; Mosquitoes- 6; Earthworm- 32; Rats - 40; Pigeon - 80; Chicken - 78; Dog - 78; Cows - 60; Horse- 64; People - 46; Guinea Pig- 64]

Chromosome size: 

From 0.2 to 50 micrometers is the length range of Chromosomes and the width range is from 0.2 to 2. Human chromosomes are about 6 in length. Not all chromosomes in a cell are the same length.

Types of Chromosomes: The numbered chromosomes known as autosomes contain genes for anything unrelated to sex. For example, humans have 22 pairs of autosomes. The gonads are what determines sex in the first place. Primary sex determination in mammals is solely determined by chromosomes and is typically unaffected by the environment. The male is typically XY and the female is typically XX. Each person must possess at least one X chromosome.

Chromosome shape : 

Different shapes of chromosomes are seen at different stages of cell division. In the interphase state they are very narrow and patchy. The shape of chromosomes in metaphase and anaphase depends on the position of the a centromere.

Chromosomes are classified into following categories based on the location of the centromere.

• Metacentric: If the centromere is in the middle of the chromosome then that chromosome is called a metacentric chromosome. Their arms are equal or nearly equal. In anaphase, such chromosomes appear 'L' shaped.
• Submetacentric: If the centromere is not exactly in the middle but slightly to the side then the chromosome is called submetacentric chromosome. In anaphase, such chromosomes appear 'B' shaped.
• Acrocentric: If the centromere is towards the ends of the chromosome then the chromosome is called an acrocentric chromosome. In anaphase, acrocentric chromosomes appear 'O' shaped.
• Telocentric: If the centromere is at the end of the chromosome then the chromosome is called a telocentric chromosome. At anaphase, the chromosomes are 'O' shaped or rod-shaped.
• Acentric: These chromosomes do not have a centromere.

Conclusion:

DNA and proteins combine to create chromosomes, which are the structures in cells that contain genetic material. They are found in the nucleus of cells and are crucial for cell division because they make sure that the genetic material is properly distributed to the progeny cells. One chromosome from each set of chromosomes is passed from each parent. There are 46 chromosomes in all, divided into 23 pairs, in people. Homologous Chromosomal pairs with the same length and centromere positions for the same loci's genes make up chromosomes. Normally, a person inherits one chromosome from their mother and one from their father. They may have different alleles, which causes different phenotypes for a single gene.