Genetics - MIT Department of Biology 7.02 Experimental...

Info icon This preview shows pages 1–4. Sign up to view the full content.

View Full Document Right Arrow Icon
MIT Department of Biology 7.02 Experimental Biology & Communication, Spring 2005 7.02/10.702 Spring 2005 7.02/10.702 Microbial Genetics Exam Study Questions These questions—adapted from old exam questions--are meant to help you prepare for the 7.02/10.702 Genetics exam on March 8 th , 2005. The exam will likely contain 4 questions based on both lecture and laboratory material. The exam is CLOSED BOOK and CLOSED NOTES , and w ill be held in the lecture hall, during normal lecture time. These study questions are not meant to be exhaustive, but should give you an idea of what topics you should study. We strongly urge you to work through these questions before looking at the answers, and bring any questions to your Undergrad TA, Grad TA or one of the Instructors. Answers to these questions will be available on the 7.02/10.702 web site! 1
Image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
7.02/10.702 Spring 2005 Question 1 You are handed an undiluted culture of pNK/KBS1 E. coli , and are told that it contains 4 x 10 11 cells/L. You also know that 1 OD550 of pNK/KBS1 = 1 x 10 8 cfu/mL. a) You want to take an OD550 of this culture. By what factor do you need to dilute the cells to ensure an accurate spectrophotometer reading of 0.25? SHOW YOUR CALCULATIONS. b) Complete the following sentence to describe how you would make 1 mL of diluted culture with an OD550 of 0.25: I would add __________ microliters (µL) of culture to __________ microliters (µL) of dilutant to obtain a final volume of 1 mL. c) If you made a 1:10,000 dilution of a culture with an OD550 of 0.25, and plated 100 µL of that diluted culture onto an LB plate, how many colonies would grow on the plate? SHOW YOUR CALCULATIONS. To set up an experiment, you mix 3 ml of undiluted pNK/KBS1 cells (titer of 4 x 10 11 cells/L) with 2 ml of P1 phage with a titer of 10 8 pfu/mL. d) Determine the MOI of this experiment. SHOW YOUR CALCULATIONS. e) Circle the experiment that the MOI calculated in part d) is more appropriate for: making P1 transducing lysates OR P1 transduction Explain your answer in two to three sentences by stating why that experiment requires that type of MOI (i.e. what do you want to happen/not happen in the experiment, and how does this kind of MOI ensure that?). 2
Image of page 2
7.02/10.702 Spring 2005 Question 2 During 7.02 lab, Andrew and Kate isolated an Ara- mutant, and observed dark blue colonies when they patched this mutant on both LB X-gal Kan plates and LB Ara X-gal Kan plates. From this data, they concluded that they had succeeded in creating an ara::lacZ translational fusion, mostly likely to the araC gene. a) The symbols shown below represent the protein product of the lacZ gene and the protein product of the wild type araC gene ( araC+ ): lacZ encoded araC +-encoded protein protein Draw a diagram of the protein product of an araC::lacZ translational fusion, and label the parts of your diagram with the appropriate protein names. b) Explain why a strain that contains an araC::lacZ translational fusion is Ara-? (Hint: What is the role of AraC in arabinose metabolism?) When Andrew and Kate made P1 transducing lysates from their Ara- strain and infected KBS1 (to stabilize their mutation), they obtained two types of transductants. Some transductants were KanR Ara- LacZ-, and others were KanR Ara+ LacZ+(constitutive).
Image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Image of page 4
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}

What students are saying

  • Left Quote Icon

    As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

    Student Picture

    Kiran Temple University Fox School of Business ‘17, Course Hero Intern

  • Left Quote Icon

    I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

    Student Picture

    Dana University of Pennsylvania ‘17, Course Hero Intern

  • Left Quote Icon

    The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

    Student Picture

    Jill Tulane University ‘16, Course Hero Intern