1 BIOL105, 2016 – Problem Set


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Hi, I need help on how to do number 6 part d of this assignment (pg. 3). Thank you. ATTACHMENT PREVIEW Download attachment PS3.pdf 1 BIOL105, 2016 – Problem Set #3 Name _______________________ Discussion Time _______________________ Warm-up and practice problems in the book. These are not to be turned in. The answers to the odd problems are in the book and to all problems are in the Solutions Manual on our course web site (5th edition). Chapter 4 problems: Solved Problem I; problems 1, 2, 6, 7, 8, 10, 11, 13, 14, 16, 19, 20 Chapter 4 problems: Solved Problem I; problems 1, 2, 4, 5, 6, 8, 9, 11, 12, 14, 17, 18 Chapter 12 problems: Solved Problem II; 33, 34, 37, 40 (and 36 is interesting) Chapter 13 problems: Solved Problem III; 34, 35, 39 The "for credit" problems below are due Monday, Jan 25 by 4:00 PM. You are welcome to write your answers on a separate sheet of paper, with your name and Discussion Section time. Please turn your PS in to the Genetics drop box outside the east door of Sinsheimer. We do not accept PSs electronically, and PSs turned in late will not earn points. We will only be grading some of your turned-in problems for a total of 6 points. 1) In Drosophila virilis, nuclei of somatic cells contain 12 chromosomes while nuclei of sperm cells contain only 6 chromosomes. What does "n" equal for this species? 2) Drosophila melanogaster has four pairs of chromosomes. Sperm from this species are formed by a meiotic process in which homologous chromosomes pair and segregate but do not undergo crossing over. How many genetically different kinds of sperm could be produced by a Drosophila melanogaster male? 3) Which of the following statements applies to homologous chromosomes? Circle one. a) b) c) d) They are attached to the same centromere. They are genetically identical. They segregate from each other at anaphase of mitosis. They contain the same genes in the same order but may have different alleles of some genes. e) More than one statement applies to homologous chromosomes. 4) Nondisjunction can occur at either the first or second division of meiosis. XYY individuals would most likely arise from nondisjunction at the ______ meiotic division in the ______. Circle one. a) b) c) d) e) first, mother second, mother first, father second, father More than 1 answer above could give rise to XYY individuals 2 5) Let’s try this again. The "cells" below are from an organism of the genotype A/a; B/b. To the right of each cell, indicate whether that cell is in mitosis, meiosis I, meiosis II, or "none" (i.e. diagram does not correctly represent a stage of normal mitosis or meiosis) – pick one answer. (For this question, ignore the effects of recombination — i.e. assume any recombination happened on the short arms.) 3 6) Aspergillus is a fungus that can exist in either a haploid or diploid state. A geneticist is interested in the genes required to synthesize leucine (an amino acid) in Aspergillus. She treats haploid cells with ultraviolet light to increase the mutation rate and obtains 5 haploid leucinerequiring mutants (named a, b, c, d, and e), all of which need leucine to be added to the medium in order for them to multiply (i.e. undergo mitotic divisions); without leucine, none of them will multiply. Note that wild-type Aspergillus can make their own leucine and don’t require it in the medium. a) How would our geneticist friend determine whether each mutation is recessive or dominant? b) What result would tell her that mutation "a" is recessive? c) She now mates the mutant haploid cells with each other to make diploid cells, and obtains the results shown below, where "+" indicates that the diploid cells multiplied on medium lacking leucine, and "-" indicates that the diploid cells were not able to multiply on medium lacking leucine. a b c d e a + + + b + + + c + + d + e What is this test called? How many genes are defined by the 5 mutations? Which, if any, mu

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