During mitosis why do the chromosomes condense before they start moving around the cell?

Answer 1

so that they can be replicated into sister chromatids and then split apart in anaphase

Answer 2

The expression

"chromosome condensation" refers to one of the oldest

recorded phenomena of the chromosome cycle in eukaryotic

cells - the cytological manifestation of chromosomes

themselves. In the most common sense the term refers to

the shortening of the chromosome axis accompanied by

contraction of the chromosome radius. This process inevitably

results in diminished chromosome volume, as

revealed by low-resolution methods (e.g. optical microscopy)

and in reduction of the exposed chromatin surface,

as seen in biochemical tests (e.g. chemical cross-linker or

nuclease accessibility). As DNA in most eukaryotic cells is

already very tightly packed into nucleosomal arrays, the

essence of condensation is likely not in the increasing density

of chromatin fiber itself, but in the folding of this fiber

in a specific manner. It is presently unclear whether

chromosome condensation in eukaryotes results in any

massive physicochemical chromatin alterations, as only a

limited set of physical characteristics has been determined

for condensed chromosomes . Thus, the term

'condensation' does not convey the full meaning of the

biological process it applies to, and should be viewed as a

simplification based on low-resolution methods of

chromosome analysis.

Despite its seemingly superficial nature, i.e. mere

refolding of chromatin fibers, chromosome condensation

is a remarkably ubiquitous process in eukaryotic cells.

Such widespread prominence of chromosome condensation

in the cell cycle led to the suspicion that its role goes

somewhat beyond the task of just making chromosomes

smaller. At the present level of knowledge, chromosome

condensation can be unequivocally classified as an

essential housekeeping function, indispensable for cell

proliferation. Therefore, chromosome condensation is a

potential target for therapeutic agents targeting cell cycle

progression.

The essential nature of chromosome condensation

has not been proven until very recently, yet this direction

of thought was based on the classic topoisomerase II

(TOPOII) study (6). Namely, TOPOII dysfunction in fission

yeast cells was shown to disrupt both chromosome

condensation and progression through anaphase.

Even though the link between the two processes was not

necessarily causal, TOPOII was known to participate in

other functions in chromatin (transcription and replication)

and the TOPOII role in chromosome condensation

turned out not to be universal, the correlation was

rather strong prompting to search for other, possibly more

specialized molecules participating in mitotic chromosome

refolding.

Answer 3

Chromosomes

condense beforemitosis

to allow them the ability to move smoothly, without becoming entangled and breaking. (So, they are conveniently packaged forcell

division

, in which the chromosomes must move to both poles of the cell.)

Answer 4

The chromosomes duplicate at the end of interphase making the cell 4N and the pachytene phase (this may be an old-fangled term) is where the chromosomes condense into discrete components so that they can "line up" for division into 2, 2N cells. Think of it as a way of organizing a pile of different colored strings into discrete units so that 1 string of each kind ends up in a different pile. If condensation didn't occur the separation would be extremely difficult.

Answer 5

At the onset of mitosis, the chromatin coils and condenses to form chromosomes. This occurs during the prophase stage of mitosis.

Answer 6

They Condense because the DNA wraps around proteins that help organize

Answer 7

So DNA does not get tangled or broken.