AS Chromosome Chromatid difference,mitosis?

Hi
rep if you can help answer this.

During mitosis at the start during interphase you call them chromosomes until anaphase where you refer to sister chromatids then at telophase they are called chromosomes again,why?
what is the big diffenece between them?

Thanks :wink:

Reply 1

ibysaiyan

Original post by hissyfit

Four Chromatids aka tetrad= A pair of chromosome.If that makes any sense :smile:

Basically prior to DNA replication you have single chromatids which later on replicate.

Reply 2

doobucks

During anaphase the chromosomes split into 2. Each half of a chromosome is called a chromatid. In interphase the chromatids are still together to make chromosomes

Reply 3

racheatworld

Original post by hissyfit

In Interphase they look like this:

Each of p and q is one chromatid, where as p & q together make one chromosome (or a sister chromosome). On the diagram above, there are 2 chromosomes attatched by the centromere as they have been duplicated. They remain like this until anaphase.

At anaphase they are referred to as the single chromatids because the chromosome has been pulled apart at the centromere by the microfibrils, and is migrating to the poles. Because the chromatids have been pulled apart in anaphase, it would be impossible to refer to them as chromosomes.

In telophase they are referred to as chromosomes again because this it the last stage of the cycle- the chromatids have been duplicated and have formed new chromosomes. Back to stage 1 so it can all continue again :smile:

Reply 4

hissyfit

Original post by racheatworld

In Interphase they look like this:

Aha! thanks I think I get it because at telophase the sister chromatids start to replicate again when they start to go into interphase again. :smile:

Reply 5

racheatworld

Original post by hissyfit

Aha! thanks I think I get it because at telophase the sister chromatids start to replicate again when they start to go into interphase again. :smile:

Yep!

Reply 6

hissyfit

Original post by racheatworld

Yep!

thank you

Reply 7

ash92:)

A replicated CHROMOSOME is 2 SISTER CHROMATIDS JOINED TOGETHER by the centromere

Hope it helped :wink:

(edited 13 years ago)

Reply 8

sy_1

was this gcse stuff? im screwed for exams this year :/

Reply 9

Sigma5116

I drew the diagram and I hope this helps.

So basically they are called sister chromatids because each of the chromatids have replicated and produced identical chromatid. It's still attached by the centromere so it's still on the same chromosome.

Reply 10

Sigma5116

Original post by ash92:)

SISTER CHROMATIDS ARE 2 CHROMOSOMES JOINED TOGETHER (CONSISTS OF A CHROMOSOME AND IT'S COPY) by the centromere

Hope it helped :wink:

I'm pretty sure one chromosome has 2 sister chromatids instead...

Reply 11

Nash24

Sorry but what is chromatin?

Reply 12

Sigma5116

Original post by Nash24

Sorry but what is chromatin?

do you mean chromatid as chromatin is completely different thing!

Reply 13

Nash24

Original post by Sigma5116

do you mean chromatid as chromatin is completely different thing!

I mean chromatin..Because I was reading the stages of meiosis and Prophase is described as:
'Condensing and supercoiling of chromatin'

Reply 14

Sigma5116

Basically chromatin is a DNA and other associated proteins which form the chromosome which is highly condensed structure. So chromatins are usually less condensed than chromosome.

Hope that Helps

Reply 15

Jellybeany

Original post by sy_1

was this gcse stuff? im screwed for exams this year :/

I didnt know this when i did GCSE :smile:

Im still trying to get my head round it :frown:

Reply 16

ash92:)

Original post by Sigma5116

I'm pretty sure one chromosome has 2 sister chromatids instead...

oooh, crap. yeh sorry it's the other way round. i'll edit that post

Reply 17

Core

I also read that during mitosis, the chromatids are called chromsomes when they reach the opposite poles of the cell, i would look this fact up as well, to be sure incase you get a question like this in the exam.