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Author Topic: What shape are chromosomes?  (Read 3741 times)

Offline cheryl j

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What shape are chromosomes?
« on: 21/02/2012 21:18:03 »
This is a dumb question. But I was looking at pictures of chromosomes and wonder if I have misunderstood something my whole life. When you see a picture of chromosome and it looks like an X, is that "the" whole chromosome, or has that chromosome copied itself  and is still stuck together by the centromere?
« Last Edit: 21/02/2012 22:03:24 by BenV »


 

Offline CliffordK

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Re: chromosomes
« Reply #1 on: 21/02/2012 21:40:39 »
  • For most of the life of the cell, chromosomes are too elongated and tenuous to be seen under a microscope.
  • Before a cell gets ready to divide by mitosis, each chromosome is duplicated (during S phase of the cell cycle).
  • As mitosis begins, the duplicated chromosomes condense into short (~ 5 Ám) structures which can be stained and easily observed under the light microscope.
  • These duplicated chromosomes are called dyads.

So, through most of the cells life, the chromosomes can not be differentiated.

They can only be photographed and differentiated during cellular replication.

So, yes, what you are seeing are two identical copies of chromosomes during the early part of cellular replication.
 

The Naked Scientists Forum

Re: chromosomes
« Reply #1 on: 21/02/2012 21:40:39 »

 

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