Chromosomes are divided into 4 types on the basis of position of the centromere as:

METACENTRIC

• The centromere is located at the centre of the chromatids and arms on either side of centromere are equal in length i.e. p=q.
• Forms V-shape during Anaphase of Mitosis.
• In Humans, chromosomes 1st, 3rd, 16th, 19th and 20th are Metacentric.
  

SUB-METACENTRIC

• The centromere is located slightly away from the centre. This results in formation of arms of unequal length.The smaller arm is called p-arm and the longer arm is called q-arm i.e. p<q
• Forms L-shape during Anaphase of Mitosis.
• In Humans, chromosomes 2nd, 4th, 5th, 6th, 7th, 8th, 9th, 10th, 11th, 12th, 17th, 18th and X are sub-metacentric.
  

ACROCENTRIC

• The centromere is located far from the centre and close to the telomere. In Acrocentric chromosomes, the difference in length of the arms is more as compared to Sub-metacentric chromosomes. (p<<q)
• Forms J-shape during Anaphase of Mitosis.
• In Humans, chromosomes 13th, 14th, 15th, 21st, 22nd and Y are acrocentric.
  

TELOCENTRIC

• The centromere is located at the terminal part of the chromosomes.
• Forms I-shape during Anaphase of MItosis.
• In Humans, this type of chromosome is usually absent