Chromosomes and types of chromosomes

 Chromosomes 

* The structure in the nucleus of cells that carries the heredity characteristics is Called the chromosomes.

* Chromosomes are made up of nucleic acids and proteins .

* Genes which contain the information about hereditary characteristics in coded form are located on chromosomes , 

* Each chromosomes is made up of DNA 

* There is a constricted region on each chromosome , This divides the chromosome into two parts Each part is called an Arm 

* Types of chromosomes 

* A chromosomes may have either equal arms or unequal arms , this depend upon the position of  centromere , the chromosomes  is of four types : 

1, Metacentric Chromosomes  :  The chromosomes in which the centromere is near the middle and the two arms are almost equal in length , is called metacentric Chromosomes . 

2. Sub-metacentric chromosomes : The chromosome in which the centromere is slightly away from the middle point and consequently its one arm is slightly short and the other arm is slightly long , is called  sub-metacentric chromosomes . 

3. Acrocentric Chromosome : The chromosome in which the centromere  is near the end and consequently  its one arm is very short  and other  is very long ., is called acrocentric chromosomes 

4. Telocentric chromosomes : The chromosomes in which the centromere is at the tip of chromosome and the arms are on one side only , is called telocentric chromosomes .