AIIMS 2006
- Exam
- AIIMS
- Year
- 2006
- Subject
- Botany
- Chapter
- Cell - The Unit of Life
AIIMS 2006 · Botany · Cell - The Unit of Life
Assertion : Polytene chromosomes have a high amount of DNA. Reason...
Assertion : Polytene chromosomes have a high amount of DNA.
Reason : Polytene chromosomes are formed by repeated replication of chromosomal DNA without separation of chromatids.
Options
- AIf both assertion and reason are true and reason is the correct explanation of the assertion
- BIf both assertion and reason are true but reason is not the correct explanation of the assertion
- CIf assertion is true, but reason is false
- DBoth assertion and reason are false statements.
Correct answer
A. If both assertion and reason are true and reason is the correct explanation of the assertion
Step-by-step 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.