Q5 / 180 · AIIMS 2006 · Botany

Assertion : Polytene chromosomes have a high amount of DNA. Reason : Polytene chromosomes are formed by repeated replication of chromosomal DNA without separation of chromatids.

  • Correct answer
    A
    If both assertion and reason are true and reason is the correct explanation of the assertion
  • B
    If both assertion and reason are true but reason is not the correct explanation of the assertion
  • C
    If assertion is true, but reason is false
  • D
    Both assertion and reason are false statements.

Solution

Polytene chromosomes are quite common in salivary glands of insects and so are called salivary chromosomes. These chromosomes have high amount of DNA of almost 1000 times in Drosophila as compared to ordinary somatic chromosomes. These chromosomes are multistranded. They are in permanent prophase stage. These chromosomese are formed by somatic pairing between homologous chromosomes and repeated replication of their chromonemata without separation of chromatids. All the chromosomes may remain attached to one another at a common point called chromocentre.

Hence, the correct answer is option: 'A'.

Relevant Questions