2010 Exam 4 - NAME: _KEY_ EXAM IV BIOLOGY 231 14 December...

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NAME: _______ KEY ____________________ EXAM IV BIOLOGY 231 14 December 2010 ________________________________________________________________________________ GENERAL INSTRUCTIONS: 1. Answer all questions legibly and concisely. 2. Confine each answer to the BOX or SPACE provided. Only what is clearly written in the box or space will be graded! Use the final page for “rough drafts” if you like. 3. SHOW YOUR WORK where appropriate. 4. Make sure that your name is PRINTED LEGIBLY on EACH PAGE. 5. This exam consists of 13 questions on 14 pages and it is worth a total of 100 points. WE WILL NOT OFFER RE-GRADING ON THIS EXAM. If you like, you can pick it up in LILY G-110 after 12/21/10. All unclaimed exams will be shredded on 1 Feb 2011. 6. Have a happy and safe holiday. Information that may be useful: ! Myosin motor proteins translocate along the surface of actin filaments, toward the plus end. ! The major motor proteins that translocate along microtubules are dyneins and kinesins. MT = abbreviation for “microtubule.” ! In the mitotic spindle, kinetochore MTs interact with chromosomes, while polar MTs interact with polar MTs from the opposite half-spindle. Astral microtubules extend toward the cell cortex. ! On this day, 14 December, in 1900 physicist Max Planck published his classic study of "blackbody" radiation, which gave rise to quantum theory (and onward, to modern physics). Eight years later he was awarded the Nobel Prize for his work. -1-
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NAME: _______ KEY ____________________ EXAM IV BIOLOGY 231 14 December 2010 ________________________________________________________________________________ (1) At right is a diagram of the lamellipodium that you have studied. We described the functions of several actin-binding proteins in this structure, including the ARP complex, cofilin, and capping protein. Answer the questions below about the lamellipodium. (a) 7 pts. Match the functions below with the single correct letter in the diagram (A-E), letters may be used more than once: severs and deploymerizes actin filaments B prevents actin filament growth at the plus ends D prevents actin filament depolymerization at the minus ends E generates the branched network of actin filaments A can bind ATP and add to a filament C bundles actin filaments in to tight, parallel arrays E nucleates actin polymerization A (b) 3 pts. Another actin-binding protein that is important for the structure and function of the lamellipodium is profilin. It binds actin monomers that have come off of the minus ends of the filaments and helps to “recycle” them into the assembly-competent form. Profilin has a close functional similarity to the GEFs (GDP exchange factors) that helped to stimulate G proteins. In a sentence or two, describe the function that they share: Both proteins bind their protein partner [ADP-actin for profilin, GDP-G protein for GEF] and stimulate it to release its XDP and bind a new XTP, stimulating its activity [activating effectors for the G protein, assembling onto filaments for actin].
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This note was uploaded on 03/12/2012 for the course BIO 231 taught by Professor Hollenbeck during the Fall '11 term at Purdue University-West Lafayette.

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2010 Exam 4 - NAME: _KEY_ EXAM IV BIOLOGY 231 14 December...

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