Concept explainers
For Problems 26–31, consider a diploid cell that contains three pairs of chromosomes designated AA, BB, and CC. Each pair contains a maternal and a paternal member (e.g., Am and Ap). Using these designations, demonstrate your understanding of mitosis and meiosis by drawing chromatid combinations as requested. Be sure to indicate when chromatids are paired as a result of replication and/or synapsis. You may wish to use a large piece of brown manila wrapping paper or a cut-up paper grocery bag for this project and to work in partnership with another student. We recommend cooperative learning as an efficacious way to develop the skills you will need for solving the problems presented throughout this text.
Are any possible combinations present during prophase of meiosis II other than those that you drew in Problem 27? If so, draw them.
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Essentials of Genetics (9th Edition) - Standalone book
- a. Manually, using a pencil, draw a cell in anaphase II from an organism in which 2n = 2 and each chromosome is metacentric. b. Given that each G1 nucleus from this organism contains 16 picograms of DNA, how many picograms of chromosomal DNA would you expect in the cell shown here?arrow_forwardIn a turtle species, a diploid cell in the G1 phase of the cell cycle contains 22 picograms of DNA (picogram is a measure of the total mass of the DNA present). How much DNA is present in a cell of the same species at prophase II of meiosis (prophase of the second meiotic division)?arrow_forwardA mitotic spindle is a structure formed in [Select] [Select] types of microtubules. [Select] while [Select] located at opposite ends of the cell. Within each of these are 3 cells that consists of a mitosis. Finally, without [Select] connection between the two spindle poles. microtubules help position each spindle, microtubules help to pull sister chromatids apart during microtubules, there would be noarrow_forward
- Mitotic nondisjunction can occur, particularly in tumor cells. Assume a single nondisjunction event involving the X chromosome occurs in a cell undergoing mitosis in a human female. First, consider the daughter cell with the smaller number of chromosomes: How many total chromosomes will this cell have? How many X chromosomes will this cell have? Next, consider the daughter cell with the larger number of chromosomes: How many total chromosomes will this cell have? How many X chromosomes will this cell have?arrow_forwardDraw and label G1 and G2 stages of interphase and each stage of mitosis (in order) for a cell that has two large and two small chromosomes, 2n=4. For unreplicated chromosome draw a line ( / ) and for replicated chromosome draw an X. Since we are focusing on the DNA, you can skip drawing the nuclear membrane or spindle fibers. For simplicity, do not indicate that the chromosomes are decondensed chromatin during interphase. Mark and label a place on one of the large chromosomes with the dominant allele of the “A” gene and put the recessive allele “a” on the other homolog. Mark and label a place on one of the small chromosomes with allele “B” and put the recessive allele “b” on the other homolog.arrow_forwardThis is a three part question: Mitosis and meiosis are both processes of eukaryotic cell division, with the same names used to describe different stags. a. What are the significant cellular and chromosomal events that occur during each stage of mitosis? b. What are the similarities and differences between the events that occur during each stage of mitosis and the corresponding stage of meiosis I? c. What are the similarities and differences between the events that occur during each stage of mitosis and the corresponding stage of meiosis II?arrow_forward
- 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.arrow_forwardUsing the data below for Allium cepa, express the total number of cells in mitosis as a percentage of the total number of cells in the field of view for Field 1. This is the mitotic index. Give your answer as a whole number (i.e. no decimals) and without any units. Total number of cells in Number of cells in: A.cepa root tip field of view M A Field 1 181 16 9 4 147 112 Field 2 12 7 6 Field 3 11 9arrow_forward6) The plant Haplepoppus gracilis is diploid (2n = 4). Inside each cell (represented here by the oval) there are four total chromosomes: one long pair (represented by "A" and "a") and one short pair (represented by "B" and “b"). The following diagrams represent possible anaphases of this cell during meiosis or mitosis. The lines represent chromosomes/chromatids being pulled to either the north or south pole of the cell, and the vertex of each "V" represent the centromere which would be attached to kinetochore microtubules. For representative cells 1– 12, say if the diagram represents a cell in anaphase I of meiosis I, anaphase II of meiosis II, anaphase of mitosis, or shows an impossible situation. If the situation is impossible, explain why. い。 VA Vb VA VB VV. V b Va VB VAVA Vo VB ^^ ^ が VaVA Vo VB くsarrow_forward
- Consider the following two meiocytes in metaphase I, with crossover positions as indicated for cell A. Solid black lines indicate spindle microtubules. Assume blue chromosomes represents paternal chromosomes and green maternal chromosomes. F G N R A B D e g a B d E Cell A Cell B i) How many chromosomes and chromatids were present in cell A during the G1 phase? Please clearly specify chromosomes and chromatids in your answer. ii) For cell A, list all the gametes that will be produced from this cell. Give the alleles of each gamete contained within a set of brackets. You may ignore independent assortment. iii) For cell B, list all the gametes that will be produced from this cell given independent assortment. Give the alleles of each gamete contained within a set of brackets. You may assume that no crossing over would take place.arrow_forwardDuring 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 . 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 , or .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 , or . In an organism with a haploid number of , how many possible combinations of maternal and paternal chromosomes can occur in its gametes? Select one: a. 72=49 b. 27=128 c.17=1 d. 214=16 384arrow_forwardDuring anaphase, the chromatids of one of the chromosomes do not separate; they both move to one side of the cell. The two chromatids of the other chromosome do separate normally. Although you could draw the nondisjoined chromosome moving in either direction (left or right), you draw it moving toward the left. This will make your answers to the questions below consistent with the grading key. Your anaphase drawing should show a cell that has two chromosomes on the left side of the cell. One of these chromosomes should have two chromatids and the other should have only one chromatid. The right side of the cell should contain a single chromosome with one chromatid. During telophase, the chromosome that failed to disjoin earlier has split. It is now two separate chromosomes. There should be three chromosomes on one side of the cell and one chromosome on the other side. All chromosomes should have one chromatid. Complete the drawings of telophase 5) Total number of chromosomes in cell A…arrow_forward
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