in metaphase 1 of meiosis, the homologous chromosomes line up side by side along the equator so that crossing over can occur between the homologous pairs and the homologous chromosomes can be pulled to opposite poles during anaphase 1. in mitosis, by contrast, homologous chromosomes line up single file along the equator. what benefits are derived from these two different ways that homologous chromosomes are positioned at metaphase in meiosis and mitosis?

in metaphase 1 of meiosis, the homologous chromosomes line up side by side along the equator so that crossing over can occur between the homologous pairs and the homologous chromosomes can be pulled to opposite poles during anaphase 1. in mitosis, by contrast, homologous chromosomes line up single file along the equator. what benefits are derived from these two different ways that homologous chromosomes are positioned at metaphase in meiosis and mitosis?

Human Biology (MindTap Course List)

11th Edition

ISBN:9781305112100

Author:Cecie Starr, Beverly McMillan

Publisher:Cecie Starr, Beverly McMillan

Chapter20: Chromosomes And Human Genetics

Section: Chapter Questions

Problem 3CT: People with Down syndrome have an extra copy of chromosome 21, for a total of 47 chromosomes....

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We are following the progress of human chromosome 1 during meiosis. At the end of prophase I, how many chromosomes, chromatids, and centromeres are present to ensure that chromosome 1 faithfully traverses meiosis?
Assume that a meiotic-nondisjunction event causes trisomy 8 in a newborn. If two of the three copies of chromosome 8 are absolutely identical, at what point during meiosis did the nondisjunction event take place?
People with Down syndrome have an extra copy of chromosome 21, for a total of 47 chromosomes. However, in a few cases of Down syndrome, 46 chromosomes are present. This total includes two normal-looking chromosomes 21, one normal chromosome 14, and a longer-than-normal chromosome 14. Interpret this observation. How can these individuals have 46 chromosomes?
Compare meiotic anaphase I with meiotic anaphase II. Which meiotic anaphase is most similar to the mitotic anaphase?
If an organism has 15 pairs of homologous chromosomes, how many chromosomes will each daughter cell have after telophase of mitosis? In this same organism, how many chromosomes will each daughter cell have after telophase II of meiosis?
During meiosis, cells undergo two rounds of nuclear and cell division, but only one round of DNA synthesis. Describe the main differences between anaphase of mitosis and anaphase I in meiosis. Why are these differences important for meiosis to occur correctly?
During meiosis, when crossing-over occurs between two homologous chromosomes, it does not happen at a single point, but rather two points with a stretch of DNA in between. What are the two junction points called?What is the region between the two points called and what is different about this region compared to how double-stranded DNA usually is?If the region described in b.) is located within a gene and the two homologues have different alleles of this gene, what might happen that is a direct violation of Mendel’s first law? (Describe the process with 2-3 sentences of detail.)
Assuming all of the chromosomes present during Meiosis II are shown in the figure above, how many chromosomes (counting homologous pairs as two chromosomes) does a cell from this organism have immediately after fertilization?
Assume that the diploid number of a certain species is four chromosomes, two large and two small (2n=4). a) Of the following figures, which represents a 3n (triploid) cell in mitotic metaphase? b) For each of the wrong answers from part (a) above, explain briefly why it cannot represent a triploid cell in mitotic metaphase.
During metaphase I of meiosis, tetrads align along the metaphase plate independently of each other. Therefore, there is a random “shuffle” of maternal and paternal chromosomes in the resulting gametes.The following diagram demonstrates how this works in a diploid cell with four chromosomes (2n=4) . Because there are two pairs of chromosomes and each pair can align in one of two ways during metaphase I, the number of possible variations in the gametes produced is 22 or 4.For an organism that is , there are three pairs of chromosomes, so the number of possible variations in the gametes produced due to independent assortment in metaphase I is 23 or 8. In an organism with a haploid number of 7, how many possible combinations of maternal and paternal chromosomes can occur in its gametes? a. 72=49 b. 27=128 c.17=1 d. 214=16 384
In kangaroos, the somatic cells are diploid, having 22 chromosomes. How many chromosomes are present in each cell at metaphase II of meiosis?
The garden pea (Pisum sativum) is normally a diploid and has 7 chromosomes in one set (in other words, n = 7). Use this information to answer the following questions: a. How many centromeres would be in a cell of a tetraploid pea plant? ______ b. How many total chromatids would be in a cell of a tetraploid pea plant in metaphase of mitosis? _______ c. How many total chromosomes would be in a cell of a pea plant that is monosomic for a single chromosome?