NAME ___________________________________BIOLOGY 205, SECTION 006 EXAM 2 SPRING 2010+ PRINT YOUR NAME AT THE TOP OF EVERY PAGE.+ USE A PEN, NOT PENCIL.+ SIGN THE HONOR PLEDGE AT THE END OF THE EXAM.+ QUESTIONS WILL BE GRADED ON BOTH HOW CORRECT AND HOW COMPLETE YOUR ANSWER IS.+ PLEASE USE ONLY THE ALLOTTED SPACE TO ANSWER EACH QUESTION. BE CONCISE.1. (2 points) What is the term for short-range cell-cell communication via secreted local mediators that act on adjacent cells?(A) Endocrine signaling(B) Paracrine signaling(C) Contact-dependent signaling(D) Delta-Notch signaling2. (2 points) A small molecule that is formed in the cytosol, or released into it, in response to an extracellular signal and that helps to relay the signal to the interior of the cell.(A) Neurotransmitter(B) Tyrosine kinase(C) GTP-binding protein(D) Second messenger3. (2 points) Communicating cell-cell junction that allows ions and small molecules to pass from the cytoplasm of one cell to the cytoplasm of the next.(A) Gap junction(B) Desmosome(C) Contact-dependent signaling(D) Enzyme-coupled receptor4. (2 points) Protein composed of three subunits, one of which is activated by the binding of GTP.(A) Ras(B) Cyclic-AMP-dependent kinase (PKA)(C) G-protein-coupled receptor (GPCR)(D) Heterotrimeric G protein5. (2 points) Protein that contributes to the desensitization of GPCRs by binding to their intracellular domain after they have been activated by ligand binding.(A) IP3 receptor(B) Arrestin(C) Protein kinase C(D) Adenylyl cyclase6. (2 points) Cell surface receptor that activates a tyrosine kinase that is noncovalently bound to the receptor.(A) Cytokine receptor(B) Receptor tyrosine kinase(C) TGFbeta receptor(D) SMAD family7. (2 points) A kinase that is involved in intracellular signaling pathways activated by cell surface receptors that phosphorylates inositol phospholipids.(A) Janus kinase (JAK)(B) TOR kinase(C) AKT kinase(D) PI-3 kinase8. (2 points) System of protein filaments in the cytoplasm of a eukaryotic cell that gives the cell its shape and the is required for cytokinesis.(A) Actin cytoskeleton(B) Microtubule cytoskeleton(C) Intermediate filaments(D) Lamins9. (2 points) A protease inhibitor that prevents the cleavage of cohesin until its ubiquitination by the anaphase promoting complex and subsequent proteolysis.(A) Separase(B) Securin(C) Condensin(D) Chiasma10. (2 points) Channel-forming protein that associates with the mitochondrial outer membrane to trigger the intrinsic apoptotic pathway.(A) Cytochrome c(B) BCL-2(C) Bak(D) Apoptosome11. (2 points) An essential component of the S-phase checkpoint that triggers cell cycle arrest pending successful DNA repair.(A) p53(B) Cdc6(C) S-Cdk(D) Caspase12. (2 points) Class of intermediate filament proteins that contribute to the mechanical stability of skin.(A) Vimentin(B) Desmin(C) Keratin(D) Lamin13. (2 points) Adhesive structures that mediate cell-cell connections between epithelial cells.(A) Hemidesmosomes(B) Gap junctions(C) Lamellipodia(D) Desmosomes14. (2 points) Actin-binding protein that organizes actin filaments in to long parallel arrays at the apical surfaces of epithelial cells.(A) Arp(B) Villin(C) Filamin(D) Cofilin15. (2 points) Microtubule-based motor protein that powers the beating of cellular protrusions such as cilia and flagella.(A) Cytoplasmic dynein(B) Axonemal dynein(C) Kinesin(D) Bi-polar kinesin16. (2 points) Chromosomal structures formed during “cross-over” between sister chromatids during meiosis.(A) Kinetochores(B) Centromeres(C) Chiasma(D) Telomeres17. (2 points) During what stage of the cell cycle does centriole duplication occur?(A) G1(B) S-phase(C) G2(D) Prometaphase18. (2 points) An enzyme that is activated by the presence of giacylglycerol (DAG) and cytoplasmic calcium released from the ER.(A) Protein kinase C(B) Protein kinase A(C) Calcium-calmodulin-dependent kinase(D) Akt kinase19. (2 points) A protein that terminates the elongation phase of growing actin filaments to maintain the population as short filaments during cellular protrusion.(A) Arp(B) Capping protein(C) Cofilin(D) Myosin I20. (2 points) A class of secreted signaling factors that induce the receiving cells to enter mitosis.(A) Mitogens(B) Growth factors(C) TGFbeta(D) Survival factors21. (10 points) The anaphase promoting complex (APC) is responsible for the initiation and completion of anaphase (or the end of mitosis) by inactivating two classes of proteins. What are these two proteins and how does the APC inactivate them?M-cyclin and securin. APC is a ubiquitin ligase that polyubiquitinates its targets thus marking them for destruction by the proteosome.22. (10 points) During anaphase, chromosome movements are driven by two types of transport: anaphase A and anaphase B movements. How are these two types of transport different and what is the basis of the forces produced?Anaphase A is the movement of chromosomes to spindle poles and is driven by the depolymerization of kinetochore microtubules. Anaphase B is overall elongation of the spindle (pole-to-pole distance) and is mediated by the combination of interpolar microtubule growth and antiparallel sliding.23. (10 points) You are examining the cellular response to a new drug. You treat cells with the drug and measure the intracellular levels of diacylglycerol and find that they increase as a response to the treatment. With what type of receptor would you predict the drug interacts and how is the rise in intracellular diacylglycerol used to change cellular physiology or metabolism?A GPCR. Activation of the GPCR activates heterotrimeric G proteins which in turn activate phospholipase C to cleave inositol lipids in to DAG and IP3. IP3 stimulates calcium release from the ER and this calcium pulse, in combination with DAG in the membrane, activate protein kinase C.24. (10 points) Mitochondria play a critical role in the process of intrinsic programmed cell death. Briefly describe the role that they play and the molecules involved from initiation of the process to the activation of executioner caspases.Bax and Bak bind to the outer mitochondrial membrane forming channels that allow the release of cytochrome c. Cytochrome c then binds to a cytosolic adaptor that clusters inactive initiator procaspase molecules and promotes their proteolytic auto-activation. These in turn activate executioner caspases.25. (10 points) Certain classes of drugs affect muscle
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