Written Questions: 3.33 points each. You must do questions 1. Then pick 2 of the remaining Questions below. Be sure to use complete sentences and/or show calculations completely please type your responses except the calculations. The 4 written unit question sets are worth 5 percent of total grade. Proving appropriate references and make sure these are in your own words. You will upload them as a word or pdf text files in Canvas.

1) Two purple sea slugs are mated with each other. Among their numerous offspring, 428 have a purple integument and 152 have orange integuments. With a chi-square test, compare the observed numbers with a 3:1 ratio and determine if the difference between observed and expected could be a result of chance.

2) Explain why tortoiseshell cats are almost always female and why their fur has patchy distributions of orange and black hairs. Please give a thorough answer.

3) Describe four differences between the processes of mitosis and meiosis. Be as specific as you can, particularly in the different stages of each process.

4) Describe the two basic laws of inheritance that Mendel developed using monohybrid and dihybrid crosses.

a. What are key differences between these laws?

b. Which law is related to each type of cross?

c. How did Mendel show which characteristic for a trait was dominant, and which was recessive?

5) The fruit fly Drosophila melanogaster is an important model system for studying inheritance in animals and genetic control of animal development, including humans. Evaluate Drosophila as a model system for human biology. What are their strengths and weaknesses as a model system?

6) What are the roles of Cohesin and Shugoshin proteins in Meiosis? When and how do they interact? When is each degraded?