Hey there! Sign in to join this conversationNew here? Join for free
x Turn on thread page Beta
    • Thread Starter
    Offline

    15
    ReputationRep:
    Any suggestions on possible answers for these questions would be much appreciated:

    Prophase:
    Why don't microtubules attach to the choromosome?

    Metaphase:
    How does a cell know that all chromosomes are attached & aligned?

    Anaphase:
    What generates the force to move the chromosomes?

    Thanks.
    Offline

    0
    ReputationRep:
    Anaphase:
    I think the protein fibres generate the forces to move the chromosones/the centrioles perhaps pull them? I've never had this question, sorry!
    • Thread Starter
    Offline

    15
    ReputationRep:
    Are these plausible answers?

    Prophase: Because microtubules and the proteins that form them are found in the cytoplasm. In prophase, the nuclear envelope is still intact and separates the kinetochores (centromeres) from the microtubule proteins.

    Metaphase: I don't know the exact nature of the signal that tells the cell that all the chromosomes are aligned. But there is a checkpoint that ensures this to be the case before metaphase ends.

    Anaphase: A microtubule motor located at the centromere and disassembly of the microtubules.
    Offline

    0
    ReputationRep:
    (Original post by hollywoodbudgie)
    Any suggestions on possible answers for these questions would be much appreciated:

    Prophase:
    Why don't microtubules attach to the choromosome?

    Metaphase:
    How does a cell know that all chromosomes are attached & aligned?

    Anaphase:
    What generates the force to move the chromosomes?

    Thanks.
    Prophase:
    Microtubules attach to kinetochores which are around the centromeric region of the chromosome and microtubules physically cannot attach to other part of centromere.

    Metaphase:
    To get into anaphase APC/C signal is needed. Inactive APC/C is activated by Cdc20 which activates separase by segregating the securin away from the inactive separase. Any kinetochores which are not properly attached will send an inhibitor for Cdc-20/APC/C inhibitor and not allowing the anaphase to take place.

    Anaphase:
    The force comes from the kinetochore microtubules shortening towards centrosomes. Centrosome is the organiser of the microtubules in mitosis and it also has astral microtubules which bind to effectively the cell membrane and gets shorter. Another microtubule which is interpolar microtubule also comes out of centrosome but it binds to another interpolar microtubule which goes to another centrosome and this gets longer.

    It's very confusing but I hope it makes sense.
 
 
 
Reply
Submit reply
Turn on thread page Beta
Updated: April 11, 2011
Poll
Do you agree with the proposed ban on plastic straws and cotton buds?

The Student Room, Get Revising and Marked by Teachers are trading names of The Student Room Group Ltd.

Register Number: 04666380 (England and Wales), VAT No. 806 8067 22 Registered Office: International House, Queens Road, Brighton, BN1 3XE

Write a reply...
Reply
Hide
Reputation gems: You get these gems as you gain rep from other members for making good contributions and giving helpful advice.