Biology 151C Dr. Caleb Rounds Exam II Fall 2013 (CE) DIRECTIONS: BEFORE DOING ANYTHING FILL IN YOUR NAME AND ID. QUESTIONS WITH LETTERS ARE MULTIPLE CHOICE, QUESTIONS WITH NUMBERED ANSWERS ARE MULTIPLE TRUE/FALSE WHERE A IS TRUE AND B IS FALSE 1. Are you in Dr. Caleb Rounds’ Introductory Biology 151C class that meets Tuesday/Thursday at 2:30 in Room 135 of the ISB? A. Yes, and I’ve filled in my ID number and the appropriate bubbles on the form. B. No, I’d like to decline the free point and I’m insulted that you would suggest I don’t want to earn my score solely on the basis of what I’ve learned. C. Wait, biology? 2. Mannose is a relatively rare sugar in the human diet so E. coli would not often need to subsist on it. Given this information what type of expression regulation do you think would be most likely? A. Positive B. Negative inducible C. Negative repressible D. Epigenetic 3. Breaking a peptide bond involves A. Adding a water molecule B. The loss of a water molecule to the surrounding system C. Hydrogen bonding D. Electrolysis E. Compensation 4. Intramolecular bonds important for holding β-sheets together A. Hydrophobic bonds B. Covalent bonds between sheets C. Ionic bonds D. Hydrogen bonds E. Disulfide bonds 5. The protein pore in the ER that allows for co-translational import includes alpha helices that face the membrane along one side and the aqueous pore on the other. These alpha helices are likely A. To consist of a random mixture of hydrophobic and hydrophilic amino acids B. To be either hydrophobic or hydrophilic C. To have R groups along one side which are hydrophobic D. To have some R groups facing in towards the core of the alpha helix E. To consist of amphiphilic amino acids.Biology 151C Dr. Caleb Rounds Exam II Fall 2013 (CE) 6. In the replica plating experiment shown above, plate 3 has complete media, plate 1 has minimal media plus amino acids and plate 2 has minimal media. What might be the problem with strain C? A. Strain C is unable to import one or more amino acids B. Strain C is unable to synthesize one or more amino acids C. Strain C is unable to break down excessive amounts of an amino acids D. Strain C is unable to repress the expression of amino acid biosynthesis enzymes E. Any of the above are possible 7. If the replica plating experiment shown above were designed to test the ability of E. coli mutants to metabolize lactose, what media would be in plates 1, 2 and 3 (in that order)? A. Complete media, minimal media –lactose + glucose, minimal media B. Minimal media, Minimal media + lactose –glucose, complete media C. Minimal media + lactose –glucose, minimal media, complete media D. Minimal media +lactose, minimal media –glucose, complete media E. Minimal media –lactose, minimal media +lactose, complete media 8. In the replica plating experiment shown above we can assume that: A. A on plate 3 and A on plate 2 are genetically identical B. C on plate 1 has some sort of mutation C. B on plate 2 and on plate 1 are different genetically D. A and B are correct E. B and C are correct 1 2 3Biology 151C Dr. Caleb Rounds Exam II Fall 2013 (CE) 9. Meat is made of a diverse group of proteins including myoglobin, actin, myosin, and tropomyosin. You take a piece of flank steak and cut it in half. One half you cook and the other you keep cold. Afterwards you extract protein from both and run them on a gel. How could you identify the actin? A. It would be larger in the cooked sample B. It would be smaller in the cooked sample C. Actin would be the same size D. You could perform a western blot with an appropriate antibody E. You could add radioactive amino acids before cooking the meat. 10. In an experiment concerning E. coli metabolism of fructose (a mono-saccharide) you test all of the characteristics shown in the table below. Given what you know about catabolic pathways in E. coli what is a possible mutation? (fructase is the fictional enzyme that digests fructose) Experiment WT Mutant Fructose only media Grows Doesn’t grow Expression of Fructase Yes Yes Fructose in cell Yes No A. Fructase is repressed inappropriately B. The fructose membrane transporter (fructose permease) is not expressed C. Fructase is non-functional D. Impossible to tell from the given information E. It could be A or C Multiple True/False 11. Two consecutive amino acids in the primary structure are never near each other in tertiary structure. F 12. The first amino acid at the N-terminus and last amino acid at the C terminus are never near each other in tertiary structure. F 13. Proteins never have both alpha helices and beta sheets. F 14. All the information for forming the tertiary structure is in the primary structure. T 15. Substitution of a single amino acid should not affect the mobility of the protein in SDS-PAGE T 16. Which of the following is not a requirement for import across a membrane? A. A pore B. An energy source C. A signal sequence D. A receptor E. A radioactive amino acid.Biology 151C Dr. Caleb Rounds Exam II Fall 2013 (CE) 17. In the experiment above radioactive methionine was added to the media for a 20 minute pulse followed by a non-radioactive media for two hours. The first lane represents the protein translated with no ER present. Lanes 2-4 are from temperature sensitive cells grown at the non-restrictive, or permissive, temperature. Lanes 5-6 represent cells from the same mutant grown at the restrictive temperature. Use this information and the experiment to answer the following questions: Why is the band in lane 4 higher than the band in lane 1? A. It has had its signal peptide cleaved B. It is in the membrane C. It may have been glycosylated D. It is now folded Which of the following are potential mutations in the temperature sensitive line (multiple true false) 18. Signal peptide cutting enzyme is mutated F 19. A GTPase involved in golgi ER movement F 20. A GTPase involved in ER golgi movement T 21. The enzyme that performs glycosylation T 22. Ubiquitination is not occurring properly F 23. The receptor for ER targeting F 24. Is the protein shown a membrane protein? A. Yes B. No C. It is impossible to tell from the given information.Biology 151C Dr. Caleb Rounds Exam II Fall 2013 (CE) Your boss wishes to know about the role of a certain protein in the cell. He’s particularly interested in whether it is involved in protein