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In onion root tip during metaphase stage of mitosis the number of kinetochores will be
a. 4
b. 8
c. 16
d. 32

Last updated date: 03rd Mar 2024
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IVSAT 2024
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Hint: Root tip of onion contains so many somatic cells, each somatic cell contains 8 chromosomes, chromosomes are condensed forms of chromatin and consist of gene pairing. Cell division undergoes mitotic division means duplication of the cell with a full number of chromosomes such as 2N will produce 2N number of cells only.

Complete answer:
• The genetic information of all organisms resides inside the person's DNA molecules or chromosomes. An onion mobile possesses 8 chromosomes whereas human cells own 46 chromosomes. Cell department takes place swiftly in growing root hints of sprouting seeds or bulbs.
• The most usually used root recommendations in labs to observe mitosis are onion, wheat, lentil, barley and alfalfa.
• An onion root tip is a rapidly growing part of the onion and as a result, many cells may be in distinctive ranges of mitosis.
• The brilliant coiled chromosomes for the duration of distinct degrees of mitosis present in the onion root tip cells may be visualized using treating with DNA unique stains, like Feulgen stain and Acetocarmine stain.
• Mitotic index is used to quantify the differences in cell department while environmental parameters are modified. Studies have already proved that the flora grown in space in microgravity have an extra mitotic index than flowers grown on the floor.
• A cell undergoing cell division has duplicated chromosomes thus a cell at metaphase stage of cell division has 16 chromosomes.
• Each chromosome has two kinetochores thus during metaphase 32 kinetochores are present.

Hence, the correct answer is option (D).

Note: Peel the onion tissue with a clean forceps and try not to twist the tissue or place it accumulated on the clean slide as if the tissue is not place properly and straight on the slide it will not show the desired result, to visualise the chromosomes under the microscope with the assist of right extraction and staining techniques.
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