Midterm+1+Key+D

Midterm+1+Key+D - \Lexl [2wa D B|8104 2/10/2012 Form D...

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Unformatted text preview: \Lexl [2wa D B|8104 2/10/2012 Form D Midterm | 1. You add a KDEL sequence to the C-terminus of collagen. Where would you now find collagen? Q's) In the ER B. In the cytoplasm C. In the Golgi D. In the ECM E. In the lysosome 2. Control of ion gradients is essential to prevent swelling of the cell due to osmotic pressures. Which of the following statements is NOT true? A. Ca++ ions are kept at a very low concentration inside the cell because they are important to signaling. B. CI- ions are kept at a higher concentration outside the cell to equalize the concentration of negatively charged organics inside the cell. Na+ ions are at a higher concentration inside the cell to balance out the negative charges from the small organic molecules. D. Water can diffuse across the membrane without a channel towards regions of higher ionic concentrations. E. Negatively charged organic molecules are at a higher concentration inside the cell than outside the cell. 3. The Langmuir trough was used in support of which of the following? A. The fluid-mosaic model B. The freeze-fracture model C. The membrane channel model ® The lipid bi—layer model E. The protein coat model 4. You isolate a mutation in a bacterial gene that codes for a fatty acid desaturase. You are now proposing to analyze membrane from this mutant strain of bacteria. What do you expect to find? A. An increase in the number of carbon double bonds and an increase in the levels of cholesterol. @. A decrease in the number of carbon double bonds and a decrease in membrane fluidity. C. An increase in the number of carbon double bonds and a decrease in membrane fluidity. D. An increase in the number of carbon double bonds and an increase in membrane fluidity. E. A decrease in the number of carbon double bonds and an increase in membrane fluidity. 5. The complexity of genomes in multi-cellular organisms increases due to an expanded number of genes involved in A. DNA replication B. cell wall biosynthesis C. DNA repair ® cell-cell communication E. protein translocation B|S104 2/10/2012 Form D Midterm | For questions 6—8: You clone a cDNA encoding a possible transmembrane protein. The mRNA made from the cDNA is translated in vitro in the presence of 35$ methionine and treated as indicated below before being resolved by SDS—PAGE and visualized by autoradiography. mRNA Q 358 meth reticulocyte 1 4 + + + microsomes - + tunicamyoin + Triton X-100 lysate 2 + + + + + + 100 kDa _ 75 kDa — 50 kDa 25 kDa 6. Why is the protein in lane 1 smaller than the one in lane 2? A. The protein in lane 2 is unfolded B. The protein in lane 1 is unfolded C. The protein in lane 2 fails to be translocated into microsomes D. The protein in lane 1 has had its signal peptide removed (E) The protein in lane 2 has been N-linked glycocylated BlS104 2/10/2012 Form D Midterm | 7. Which of the following best describes the topology of the protein? A. It crosses the membrane twice with its N-terminus in the cytosol. B. It is a luminal protein with no transmembrane domains. © It crosses the membrane three times with its N-terminus in the ER lumen. D. It crosses the membrane 4 times with its N-terminus in the cytosol E. It crosses the membrane once with its N-terminus in the ER lumen. 8. Why is there protein in lane 6, but not lane 7? ® In lane 7, the microsomes are permeable to the protease B. Lane 7 is missing SRP receptor C. In lane 7, the translocon is always open D. Lane 7 is missing SRP E. Lane 7 is missing signal peptidase 9. In general, mutations in tumor suppressor genes that lead to the progression of cancer are while mutations in oncogenes that lead to cancer progression are . dominant; recessive ‘3 recessive; dominant C. recessive; proto D. harmful; protective E. protective; harmful 10. In problem set #1, you looked up the localization pattern of two polymerases MlP1 and POL1. Given where you found these two proteins localized, which of the following are true? ® MlP1 and POL1 could be separated by a 1000x g spin B. MlP1 and POL1 could be separated by a 50,000 x 9 spin C. You need an electron microscope to resolve MlP1 from POL1 D. These proteins were localized in the paper you read by immunofluorescence E. MlP1 and POL1 are made at the ER membrane 11. The amphipathic nature of phospholipids leads to them rarely A. Pack closely to cholesterol molecules B. Rotate within the bilayer Flip from one half of the lipid bilayer to the other . Flex their tails E. Place their heads next to water 12. Which of the following statements best describes the role of Protein A? A. Protein A is an important component for translocation B. Protein A comes from Myobacterium tuberculosis C. Protein A binds the Fab region D. Protein A is an important reagent in western blotting Protein A is an important reagent in immunOprecipitations BIS104 2/10/2012 Form D Midterm | 13-15. Using sequential differential centrifugation steps, you fractionate cellular organelles. You then run the fractions on an SDS—PAGE gel and detect your favorite proteins (A-E) by western analysis to determine which fraction they are in, resulting in the following results: A. B. C. D. E. + 13. Where does protein E reside? A. Cytosol B. Plasma membrane © Mitochondria D. Microsomes E. Nucleus Crude Lysate 12,000Xg pellet 12,000xg supernatant 1000xg supernatant 50,000xg pellet 50,000xg supernatant 14. You closely examine the sequences ofthe proteins. Which protein is most likely the manose—6-phosphate receptor? A. Protein A B. Protein B © Protein C D. Protein D E. Protein E 15. Which protein has the largest molecular weight? ® Protein A B. Protein B C. Protein C D. Protein D E. Protein E BIS’IO4 2/10/2012 Form D :lterm | carbohydrate 16. Which of the following proteins \ Egg Extracellular Space would you NOT expect to find in a c 9 Q3} typical eukaryotic cell? g A. A i ‘F’-\ B. B lillllllllllilltlllillllllg .ll’léllllillg‘fillit $33 lllllllllllllllllll‘lllllti;225llllllllllll E. E . “mill l my v. 1 .a J,._1 F I _ cytosol v.15 -' 17. From your reading in problem set two on the molecular anatomy of a vesicle, which of the following is true? A. A vesicle has one only kind of v-SNARE and only one kind of Rab to bind to a specific membrane. B. The surface area of a vesicle is almost entirely lipids with very few proteins. C. More of the surface area of a vesicle is covered by proteins than lipids. @The most abundant protein in a vesicle is a SNARE, at over 70 copies per vesicle. E. The lipid make-up of the vesicle is uniform, almost all the lipids are phosphatidylcholine. 18. BiP is normally a component of the ER lumen. You add a “stop transfer” signal of about 20 hydrophobic amino acids to the middle of the BiP protein sequence. Where would you now predict the bulk of BiP to localize? A. The lysosome B. The ER lumen C. Secreted outside the cell . The ER membrane The plasma membrane 19. BiP is normally a component of the ER lumen. You delete the first eight hydrophobic amino acids. Where would you now predict the majority of BiP to now localize? A. The ER B. The Golgi C. Equally split between one or more of the locations above ® Secreted outside the cell E. The cytosol 20. Which of the following is the smallest cellular object you can resolve two of using a light microscope? Nuclei B. Individual cisternae of the Golgi stack in an animal cell C. Gut endothelial cells D. Ribosomes at translocons E. Clathrin coated vesicles B|S104 2/10/2012 Form D Midterm I 21. Defects in the Cl— channel CFTR are responsible for the disease Cystic fibrosis. The most common mutation in CFTR is a deletion of F508. This mutation prevents CFTR from leaving the ER, probably due to protein mis-folding which leads to and retention by the chaperone A. glucose addition, BiP ® glucose addition, calnexin C. 9-mannose-phosphate addition, BiP D. 5—mannose—phosphate addition, calnexin E. N—acetylglucosamine addition, mannose—6-phosphate receptor 22. Proteins destined for the mitochondrial membrane are made in the and delivered to the mitochondria by . A. Cytoplasm; Clathrin coated vesicles B. ER membrane; vesicular transport © Cytoplasm; by mitochondrial protein Channels D. ER membrane; translocon E. Cytoplasm; COPll vesicles 23. Normally, the H+ ATPase pump is found in the lysosomal membrane. In the cells from l-cell patients, the H+ ATPase pump fails to be and is localized A. modified with phosphate; in the endoplasmic reticulum B. modified with sugar; in the lysosome C. translocated; in the cytosol ® modified with phosphate; to the plasma membrane E. modified with sugar; secreted outside the cell 24. in class we watched a time-lapse video of a yeast cell that expressed the early Golgi enzyme Vrg4 fused to GFP and the late Golgi enzyme Sec? fused to dsRed. The data in this video . supported the cisternal maturation model. demonstrated that it takes 6 minutes for cargo to move through the Golgi. showed that resident enzymes are permanently in a particular cistarnae. showed that resident enzymes are kept in the Golgi by anterograde trafficking. supported the vesicle transport model. mpowg 25. High salt is used to extract the following from microsomes: A. The SRP Receptor Peripheral membrane proteins C. Transmembrane proteins D. Signal peptidase E. Lumenal proteins Bl8104 2/10/2012 Form D Midterm | The following graph pertains to questions 26-27: hydrophobic 3 11 do hilic y 1 p 100 200 300 amino acid number 26. After cloning the cDNA for a new protein, you determine its sequence. Based on the predicted amino acid sequence, you create a hydrophobicity plot (above) and predict that the protein . A. Spans the membrane seven times B. Spans the membrane six times © Spans the membrane five times D. Spans the membrane four times E. Spans the membrane two times 27. According to the hydrophobicity plot above, what would you predict is the topology of the protein? A. Regions 2 and 4 would be outside the cell. Regions 2 and 4 would be in the cytoplasm. C. Regions 1 and 3 would be outside the cell. D. Regions 1, 2, and 4 would be in the cytoplasm. E. Regions 1 and 4 would be outside the cell. 28. Glucose is moved into intestinal epithelial cells against its concentration gradient using , which is made possible by establishing potential energy through the Na+ symporter; Na+/K+ ATPase . Glucose ATPase pump; glucose channel C. Glucose ATPase pump; facilitated transporter D. Na+ antiporter; Na+/K+ ATPase E. K+ symporter; Na+/K+ ATPase 29. In problem set one, you determined where proteins localized using a database. What types of cells were used for that database? A. Acinar cells B. Worm cells C. HeLa cells D. Fibroblasts ©Yeast cells BIS’IO4 2/10/2012 Form D Midterm | 30. An infant, that is unable to acquire antibodies properly from his mother's breast milk, is born. Tests determine that he makes receptors for the antibodies, but they are mutant, containing a tyrosine to cystine mutation. The antibody receptors efficiently bind the antibodies on the plasma membrane, but are not observed in coated pits. The mutation in the receptor is in . A. The GAP activity domain. ® The AP-2 binding domain C. The signal peptidase recognition sequence. D. The domain that binds to the mother’s antibodies. E. The Clathrin binding domain. 31-33. Consider a yeast protein that is normally secreted and two Sec genes with made up names (so don’t worry-—you are not supposed to know what 8e098 or 8e099 are). In a 8e098 mutant at the restrictive temperature‘, the protein that is normally secreted abnormally accumulates in the cytoplasm and there is a small ER. In a SecQQ mutant at the restrictive temperature, the protein accumulates in a bloated ER. 31. What conclusion can you make? ® SecQ8 and 8e099 are necessary for secretion B. Sec98 and 8e099 are sufficient for secretion C. We can not make a conclusion about necessity or sufficiency D. SecQ8 is sufficient for getting protein into the ER and Sec 99 is necessary for protein exiting the ER E. 8e098 is necessary for getting protein into the ER and Sec 99 is sufficient for protein exiting the ER 32. Hypothesize what 8e098 might be. A. A coat protein B. A vesicle fusion factor © A component of the SRP D. A chaperone in the ER E. An component of the ribosome that functions to translate mRNA 33. What would you predict is the mutant phenotype for a 8e098; SecQQ double mutant at the restrictive temperature? A. The size of the ER is normal ® The size of the ER is small C. Secreted protein will accumulate in the ER D. Secreted protein will be normally secreted E. The size of the ER is bloated Make sure your form is properly marked and that the bubbles for your student ID are properly filled in. (worth 1 point) ...
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This note was uploaded on 03/31/2012 for the course BIS 104 taught by Professor Scholey during the Winter '08 term at UC Davis.

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Midterm+1+Key+D - \Lexl [2wa D B|8104 2/10/2012 Form D...

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