The Student Room Group

biology pmt question

in one tissue,the scientists found a genetic mutation that stopped the metaphase checkpoint from working.

suggest an abnormality the scientists might observe in the cells of this tissue?

answer:idea that some cells contain incorrect number of chromosomes

why do the cells contain incorrect no of chromosomes if the metaphase checkpoint check if the sister chromatids is attached to te centrome
Original post by user1034723
in one tissue,the scientists found a genetic mutation that stopped the metaphase checkpoint from working.

suggest an abnormality the scientists might observe in the cells of this tissue?

answer:idea that some cells contain incorrect number of chromosomes

why do the cells contain incorrect no of chromosomes if the metaphase checkpoint check if the sister chromatids is attached to te centrome


To answer your question, first you should understand what happens in Metaphase and what the implications are if something goes wrong in it.

Metaphase is when the mitotic spindle forms and attaches to all the chromosomes (by this stage they should be duplicated and lined up along the cell equator). The next step, or phase, is cell division, called anaphase. During this phase, the mitotic spindle will shorten and retract back to their respective poles, dragging the chromosomes along with them to opposite poles (ends) of the cell. The cell membrane pinches down in between the two groups of identical chromosomes more and more until 2 separate daughter cells form. This causes the 2 new daughter cells to enclose around the two separate groups of chromosomes and each daughter cell should be identical, with the same number of chromosomes in the cell they came from (if this is mitosis in a somatic cell).

If metaphase was not working, then one of the things that can go wrong include the spindle not forming; most importantly, if it fails to attach to some chromosomes, then when the spindle retracts and the new cells form around the new groups of chromosomes, whatever was not attached will not be taken to the poles of the parent cell and will not be in the 2 new daughter cells when the parent cell divides. In this case, there will be less chromosomes in the new daughter cells.
Hope that is clear for you.
Original post by martinthemartian
To answer your question, first you should understand what happens in Metaphase and what the implications are if something goes wrong in it.

Metaphase is when the mitotic spindle forms and attaches to all the chromosomes (by this stage they should be duplicated and lined up along the cell equator). The next step, or phase, is cell division, called anaphase. During this phase, the mitotic spindle will shorten and retract back to their respective poles, dragging the chromosomes along with them to opposite poles (ends) of the cell. The cell membrane pinches down in between the two groups of identical chromosomes more and more until 2 separate daughter cells form. This causes the 2 new daughter cells to enclose around the two separate groups of chromosomes and each daughter cell should be identical, with the same number of chromosomes in the cell they came from (if this is mitosis in a somatic cell).

If metaphase was not working, then one of the things that can go wrong include the spindle not forming; most importantly, if it fails to attach to some chromosomes, then when the spindle retracts and the new cells form around the new groups of chromosomes, whatever was not attached will not be taken to the poles of the parent cell and will not be in the 2 new daughter cells when the parent cell divides. In this case, there will be less chromosomes in the new daughter cells.
Hope that is clear for you.


tysm:smile:
if the metaphase stops working wont everything stop working and then would there not be 0 chromosomes instead of less?
Original post by user1034723
tysm:smile:
if the metaphase stops working wont everything stop working and then would there not be 0 chromosomes instead of less?

Not working properly doesn't necessarily mean it stops completely. And, there are many ways it can "not work properly". For example, one of the ways it can "not work properly" is not checking if everything is attached. If some are not attached, that would lead to missing chromosomes. If however the spindles don't form at all, then there will be no cell division.

Quick Reply

Latest

Trending

Trending