do chromosomes ALWAYS have 2 chromatids attached at the centromere?
thanks in advance.
thanks in advance.
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False.
Before your chromosomes replicate, they are also called chromosomes (the left one in the image)
http://www.google.com.sg/imgres?q=chromo…
When they replicate to form two sister chromatids, it is also called a chromosome.
http://www.janewhitney.com/img/sister_ch…
When a cell divides, those two sister chromatids separate from one another. At the instant they separate, you no longer have one chromosome composed of two sister chromatids, but you now have two chromosomes, each of which is a complete chromosome (since they were replicated prior to division)
That's what I learned anyway. =)
Before your chromosomes replicate, they are also called chromosomes (the left one in the image)
http://www.google.com.sg/imgres?q=chromo…
When they replicate to form two sister chromatids, it is also called a chromosome.
http://www.janewhitney.com/img/sister_ch…
When a cell divides, those two sister chromatids separate from one another. At the instant they separate, you no longer have one chromosome composed of two sister chromatids, but you now have two chromosomes, each of which is a complete chromosome (since they were replicated prior to division)
That's what I learned anyway. =)
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FALSE!!!
All of the answers are WRONG, with the one exception of Zanier Life, who gave the correct answer.
Consider the middle of mitosis. In metaphase the chromosomes are lined up at the cell's equator - each chromosome consists of 2 sister chromatids. In anaphase, the centromeres of the chromosomes break and the two sister chromatids of each chromosome separate and begin being moved towards opposite poles. The key point here is that as soon as the sister chromatids separate, each one is the considered a chromosome. So what was 1 chromosome consisting of 2 sister chromatids becomes 2 chromosomes each consisting of 1 chromatid.
All of the answers are WRONG, with the one exception of Zanier Life, who gave the correct answer.
Consider the middle of mitosis. In metaphase the chromosomes are lined up at the cell's equator - each chromosome consists of 2 sister chromatids. In anaphase, the centromeres of the chromosomes break and the two sister chromatids of each chromosome separate and begin being moved towards opposite poles. The key point here is that as soon as the sister chromatids separate, each one is the considered a chromosome. So what was 1 chromosome consisting of 2 sister chromatids becomes 2 chromosomes each consisting of 1 chromatid.
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Yes, otherwise they wouldn't have the required number of genes.
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TRUE.
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true
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true