From a piece of blank paper, cut out three sets of four cigar-sha...

Question

From a piece of blank paper, cut out three sets of four cigar-shaped structures (a total of 12 structures). These will represent chromatids. Be sure each member of a set of four chromatids has the same length and girth. In set one, label two chromatids 'A' and two chromatids 'a.' Cut each of these chromatids about halfway across near their midpoint and slide the two 'A' chromatids together at the cuts, to form a single set of attached sister chromatids. Do the same for the 'a' chromatids. In the second set of four chromatids, label two 'B' and two 'b.' Cut and slide these together as you did for the first set, joining the 'B' chromatids together and the 'b' chromatids together. Repeat this process for the third set of chromatids, labeling them as 'D' and 'd.' You now have models for three pairs of homologous chromosomes, for a total of six chromosomes.

Align the chromosomes as they might appear at metaphase of mitosis.

Accepted Answer

Everyone. Let's take a look at this question together which of the following statements is incorrect. About the alignment of homologous chromosomes as they might appear during the meta phase stage of mitosis. Is it answer choice A they align themselves at the meta phase plate. Answer choice B, they can dense and become visible under the microscope. Answer choice C the spindle fibers align the chromosomes in a single file fashion or answer choice D the sister chromatid separate at the centromere. Let's work this problem out together to try to figure out which of the following statements about the alignment of homologous chromosomes during metaphasis is incorrect. So let's recall what we've learned about what happens during meta phase in mitosis. So during meta phase, we know that the homologous chromosomes a line at the meta phase, right? And we also note that they condense and become visible under hey microscope. And lastly, we know that the fibers a line the chromosomes in a linear conard. And so looking at our answer choices, we want to identify which of the following statements is incorrect. Well, answer choice A says that they align themselves at the meta phase plate which we know that those homologous chromosomes align at the meta phase plate. So answer choice A is true. Answer. Choice B says that they condense and become visible under a microscope which we know that that statement is also a true statement. Answer choice C says that the spindle fibers align the chromosomes in a single file fashion, which we know that the spindle fibers are responsible for the chromosomes being aligned in that linear single file fashion. So answer choice C is also a true statement which means that by process of elimination, answer choice D must be an incorrect statement. Making answer choice D the sister chromatid separate at the centromere, the correct answer. And we also know that answer choice D is an incorrect statement about the alignment of homologous chromosomes during meta phase of mitosis because the sister chromatid separating at the centromere occurs during an a phase and not during meta phase. So answer choice D is an incorrect statement making it the correct answer. I hope you found this video to be helpful. Thank you and goodbye.

Key Concepts

Chromatids

Homologous Chromosomes

Metaphase of Mitosis

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