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bio AS ..doubt !!:(

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Metallicnak:
Hey guys, i was just going through my cell division notes and came across this doubt that annoys me preety much:

During the interphase of Mieosis the the DNA which is in the form of chromatin replicates and by Prophase 1 the chromatin condense forming chromasomes. Each chromasome then pairs up to its identical to form a Homalogous pair right?  So does homologous chromasomes form during the prophase of Mitosis as well ??? Oh and the other thing is that when homolougous chromasomes are formed are the chromasomes whithin the pair exactly identical to each other ???

Much help would be appreciated :)

nid404:
I'll try my best to explain...
It's highly complex genetics...but i like it  ::)

In most eukaryotic cells, there are two sets of chromosomes.
The presence of two sets is a consequence of sexual
reproduction; one set is inherited from the male parent
and the other from the female parent. Each chromosome in
one set has a corresponding chromosome in the other set,
together constituting a homologous pair..
The two chromosomes of a homologous pair are usually
alike in structure and size, and each carries genetic
information for the same set of hereditary characteristics.
(An exception is the sex chromosomes)

For example, if a gene on a particular
chromosome encodes a characteristic such as hair color,
another gene (called an allele) at the same position on that
chromosome’s homolog also encodes hair color. However,
these two alleles need not be identical: one might produce
red hair and the other might produce blond hair. Thus,
most cells carry two sets of genetic information; these cells
are diploid. But not all eukaryotic cells are diploid: reproductive
cells (such as eggs, sperm, and spores) and even
nonreproductive cells in some organisms may contain a single
set of chromosomes. Cells with a single set of chromosomes
are haploid.Haploid cells have only one copy of each
gene.

Metallicnak:
Thanks Nid tht cleared up preety much about the homologous chromasomes  :D, but does homologous pair form during the prophase of mitosis... like in Prophase 1 of mieosis ???

MaNi_DaDuDe:

--- Quote from: Metallicnak on April 06, 2010, 01:34:27 pm ---Thanks Nid tht cleared up preety much about the homologous chromasomes  :D, but does homologous pair form during the prophase of mitosis... like in Prophase 1 of mieosis ???

--- End quote ---

no. Mitosis has no homologous pairing.. no bivalents..

If you still don't understand, check : http://www.le.ac.uk/ge/genie/vgec/he/cellcycle.html

Metallicnak:
Thanks fr the info mani ;D By the way do u also happen to know any other usefull sites for Bio like this 1 maybe with animations and all would be really helpfull while studying.

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