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If you are provided with root-tips of onion in your class and are asked to count the chromosomes which of the following stages can you most conveniently look into :-
A
Telophase
B
Anaphase
C
Prophase
D
Metaphase
Detailed Solution
In metaphase of mitosis, the chromosomes are maximally condensed (shortest and thickest), and the nuclear envelope has disappeared.
All the chromosomes line up at the equator (metaphase plate), each attached to spindle fibres at its centromere, so they are well separated and clearly visible.
This makes metaphase the best stage to study chromosome morphology and to count the chromosomes (karyotyping is also done at metaphase).
In prophase the chromosomes are still long and tangled; in anaphase they are moving apart; in telophase they decondense.
So the most convenient stage for counting chromosomes is metaphase.
All the chromosomes line up at the equator (metaphase plate), each attached to spindle fibres at its centromere, so they are well separated and clearly visible.
This makes metaphase the best stage to study chromosome morphology and to count the chromosomes (karyotyping is also done at metaphase).
In prophase the chromosomes are still long and tangled; in anaphase they are moving apart; in telophase they decondense.
So the most convenient stage for counting chromosomes is metaphase.