BIOL 404-Answer-Key-BIOL-404

BIOL 404-Answer-Key-BIOL-404 BIOLOGY 404 FALL 2014 TAKE HOME PORTION OF EXAM I DIRECTIONS There are three sets (#1-#3) of two questions. You may answer one question from each set (A or B). You must do the sets in order - they are of increasing difficulty. Clearly indicate which question in the set you have chosen. Write concisely. Answers must be legibly written or typed. RULES Very few: You may use any resource you wish except Mike Cancro. We encourage forming working groups; however, submitting multiple verbatim copies of a single answer is inappropriate. If you use a working group to solve the problems, please prepare your final answer in your own words. Of course, you may proof one another's final answers for content and clarity. GRADING Each question is worth 15 chips. They will be marked stringently, since you have ample time to complete the work conscientiously. An answer for set 2 will only be graded if you have answered one from set 1, and an answer for set 3 will only be graded if both 1 and 2 have answers. Work judged illegible by Mike, Naomi, or Theresa will be returned for "translation," and will then be graded based on half the original maximum value. A PAPER COPY OF YOUR COMPLETED TAKE HOME EXAM IS DUE WHEN YOU TURN IN YOUR IN-CLASS EXAM THE EVENING OF OCT 27th, 2014. NO PAPERS WILL BE ACCEPTED LATE. NO EXCEPTIONS. SET 1 CHOICE A A family has six members: Mom & Dad; a pair of monozygotic twins named Thelma & Louise; and a pair of dizygotic twins named Jack & Mack. Mom and Dad are both heterozygous at the Ig heavy and light chain loci, and share no alleles. You purified mu heavy chains and kappa light chains from Thelma’s serum and used them separately to immunize Mom, Dad and the pet parrot named Squawk. (That's six antisera in all). Answer each of the following questions and concisely explain your reasoning. • Will any of the six antisera specificities be exactly the same? Explain your reasoning. (3 Chips, 1 for answer, 1 for okay reasoning and 2 for good reasoning) No, none of the antisera specificities will be the same. The okay reason is that they will be different because of variability within the immune responses, leading to specificities against various regions of the immunized heavy and kappa chains. Good reason included that Mom would not mount a response against the chains inherited from her, Dad would not mount a response against what was inherited from him and Squawk would respond against all of it. • Construct a table that indicates the probability of each anti-mu antiserum reacting with IgMs in the serum of each family member. Construct a table that indicates the probability of each anti-kappa antiserum reacting with kappa bearing immunoglobulins in the serum of each family member. (5 Chips, 1 off per row that has a wrong answer) Serum Mom Dad Thelma Louise Jack Mack Mom α–mu antiserum 50 Dad α –mu antiserum 50 Squawk α –mu antiserum 75 Mom Dad Thelma Louise Jack Mack Mom α–kappa antiserum 50 Dad α –kappa antiserum 50 Squawk α –kappa antiserum 75 Rationale: Thelma and Louise are monozygotic twins, meaning that they share the all germline genetic material. Jack and Mack are dizygotic twins, which makes them as likely to be related genetically to each other as any other two siblings (although that does not matter for this question). The kappa light chains and the mu heavy chains are inherited independently of each other and are expressed co-dominantly throughout the person. Mom and Dad are both heterozygous at both loci and share no alleles; we can draw a Punnet square to determine probability of inheriting each loci. To look at this problem for mu, let’s say Thelma inherited AC, A from Dad, C from Mom. This would mean that in her serum, there would be A and C heavy chain. When these chains are injected mu Mom C D Dad A AC AD B BC BD into Mom, she will create an immune response that reacts against the A chain from Dad, but not the C chain that she has. The reverse being true for Dad, and Squawk reacting to both A and C. The two easiest columns to fill in are Thelma and Louise. Since they are genetically identical and Thelma’s mu proteins were used to immunize Mom, Dad and Squawk, every antiserum will have a 100% probability to react with T&L’s serums. The anti-mu antiserum that comes from Mom will never react with her own serum (0%), due to her non-reactivity to self. It will 10