Bio151 WI22-23 Topic 10 Problem Set

Bio151 WI22-23 Topic 10 Problem Set

A Sample Answer For the Assignment: Bio151 WI22-23 Topic 10 Problem Set

Title:  Bio151 WI22-23 Topic 10 Problem Set

Instructions: ✓ Download this problem set, keep the questions in the document and please type your answers in a color other than black so that your answers are easily discernable. ✓ Complete this entire problem set – give robust, detailed responses – this is practice so use it as such. ✓ If you get stuck or need clarification on any of these questions… just ask! ✓ Upload this document with your answers to the appropriate TurnItIn link in our Moodle page in PDF format ✓ Please be advised that TurnItIn is a plagiarism and similarity checking software o You are always welcome to work with other people and/or get help on the problem set, however… o Make sure that you close and put away all sources of information before writing your answers so that you can be sure that your answers are in your own words and to convince yourself that you understand the concept and can explain it yourself. o If your answers are too similar to either someone else’s responses (past or present) or from the internet, points will be deducted as the assumption will be made that the work you’re doing is not your own. Complete the entire problem set. For grading, a problem or two will be randomly chosen for grading of 10 points and will be graded for completeness and originality worth 5 points; 15 points total. Due date: Saturday, February 4th by 11:59pm Question 1: Mitosis vs Meiosis Explain the difference between mitosis (the cell division cycle we already talked about) and meiosis, including an explanation of how the mitotic process maintains chromosome number while meiosis reduces the number of chromosomes (typically from diploid to haploid). Bio151 WI22-23 Topic 10 Problem Set Francis Question 2: Haploid vs Diploid Explain the terms haploid and diploid in your own words. Make sure to include an explanation of alleles in your answer. Question 3: Where did the Chromosomes Come From? In sexual reproduction, somatic cells of organisms are diploid, which means they contain two pairs of each chromosome. Briefly explain where each set of these chromosomes came from. Question 4: Meiosis Problem-Solving You are studying a cell and trying to figure out at what meiotic stage it’s at in the moment you’re looking at it. The cell is haploid but you notice that there are two duplicates of each chromosome. You also notice that the chromosomes are arranged at the “metaphase plate”. What is the meiotic stage? Explain. Question 5: Nondisjunction Gametes (the product of meiosis) are supposed to be haploid. How could a nondisjunction event lead to a gamete that is diploid in chromosome? What would be the result if that gamete were used in sexual reproduction? Bio151 WI22-23 Topic 10 Problem Set Francis B. When a nondisjunction event occurs in meiosis I, all of the resulting gametes have an abnormal number of chromosomes. Whereas when a nondisjunction event occurs in meiosis II, only two of the four resulting gametes has an abnormal number of chromosomes. Explain what is happening to lead to this phenomenon. Question 6: Trisomy Down syndrome (trisomy 21) and Edwards syndrome (trisomy 18) are the most common autosomal trisomies seen in human infants. Why aren’t other trisomy situations typically observed in human infants? Is it that non-disjunction events just aren’t occurring in the other chromosomes or is something else going on? Question 7: Karyotypes From the internet, find a normal karyotype and then find a karyotype from a cell from a tumor. Copy and paste those images into your document. Discuss what you see in the abnormal karyotype – what are the ways in which the chromosomes are abnormal and what do you think is going on that leads to Bio151 WI22-23 Topic 10 Problem Set Francis these abnormalities? You can use what you learned in the cell cycle regulation topic for this question as well. Mendelian Inheritance Patterns Question 8: Recessive Alleles Which of the following statements about recessive alleles is/are correct? Yes or no for each and explain your reasoning. A. They are harmful to the bearer. B. They are expressed phenotypically when homozygous. C. They are masked by dominant alleles in heterozygous individuals. D. If X-linked, their expression is observed less frequently in males. Bio151 WI22-23 Topic 10 Problem Set Francis Question 9: Recessive vs Dominant Alleles What does it mean that an allele is “dominant” or “recessive”? Discussion genotype and phenotype with respect to these terms. Question 10: Fruit Fly Wing Shape A single gene has a profound effect on wing shape in fruit flies. Two flies with normally shaped wings are mated that produce varied offspring, some with normal wings and others with abnormally-shaped wings. Assuming that the gene for wing shape is autosomally inherited, is the gene for abnormally shaped wings dominant or recessive? Explain your reasoning. Questions 11: X-linked Inheritance In humans, there is a gene that allows for red-green color detection. This gene is on the X-chromosome and therefore is X-linked. A loss of function in the gene leads to red-green color blindness. One wildtype (functional) allele allows a person to see red-green colors. If Victor is red/green color-blind, and both of Victor’s parents have normal color vision then: A. Which of Victor’s parents did Victor receive the color-blind gene from? Explain. Bio151 WI22-23 Topic 10 Problem Set Francis B. Which of Victor’s grandparents COULD be red/green color-blind? Your choices are Maternal grandmother; Maternal grandfather; Paternal grandmother; Paternal grandfather. Explain yes or no for each grandparent and why. Question 12: Y-linked Inheritance Although there aren’t many genes on the Y chromosome, there are a few. Why is it that we don’t discuss recessive and dominant inheritance in relation to Y-linked genes? Non-Mendelian Inheritance Patterns Question 13: Incomplete Dominance Suppose you have two rose plants, both with pink flowers. You cross the two plants and are surprised to find that, while most of the offspring are pink, some are red and some are white. You decide that you like the red flowers and would like to make more. What cross would you perform to produce the most red flowered plants? Explain your reasoning. Bio151 WI22-23 Topic 10 Problem Set Francis Question 14: Co-dominance A. If a woman has blood type A and her child has blood type O, could the dad of the child have blood type B? Explain. B. Two parents, both of blood group A, have a daughter of blood group O. What is the probability that their next child will be a boy who has blood group O? Explain. Pedigree Analysis Question 15: Pedigree Analysis I Use this pedigree for the following questions. The inheritance for this trait is autosomal, not sex-linked. A. Who in this family must be homozygous? Bio151 WI22-23 Topic 10 Problem Set Francis B. Who in this family must be heterozygous? Question 16: Pedigree Analysis II Use the following pedigree for this question: Given this pedigree and the additional information that I-1, I-2, I-3 and I-4 are all homozygous individuals for the phenotype displayed in this pedigree, could this be: Yes or no, explain reasoning Autosomal recessive inheritance? Autosomal dominant inheritance? X-linked recessive? X-linked dominant? Bio151 WI22-23 Topic 10 Problem Set Francis Question 17: Pedigree Analysis III Which of the following could be modes of inheritance for this trait? If yes, explain generally why, if no, explain where the inheritance pattern breaks down for that mode of inheritance. A. Autosomal recessive B. Autosomal dominant C. X-linked recessive D. X-linked dominant

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