Answer keyFinal Exam, BIO201B, 2005 Form 1Name_______________________________Each question has only one right answer. Choose the best answer for each.1. Which of the following best describes what happens in human mitotic prophase?A. The spindle forms, DNA condenses and mitotic chromosomes are seen as paired sister chromatidsB. Homologous chromosomes pair (attached at their centromeres by synaptonemal complexes) and the nuclear membrane breaks downC. The cell goes from 2n2x2c to 2n4x4c as chromatids pair up and chromosomal microtubules begin to make contact with kinetochoresD. Chromatin compaction enables sister chromatids to pair and arrange in syntelic orientation, the ER and golgi break down and microtubules begin to grow out from the centriolesE. Mitotic chromosomes begin to move toward the spindle equator, held together by condensin, compactin and chiasmata2. Which of the following does not occur in rough endoplasmic reticulum?A. Synthesis of soluble proteinsB. Addition of core carbohydrates to proteinsC. Glycosylation of lipidsD. Steroid hormone synthesisE. Phospholipid synthesis3. If two types of large particles have the same densities but very different S values:A. They can’t be separated by centrifugation but could be separated by polyacrylamide electrophoresisB. They can be separated by density gradient centrifugation but not by differential centrifugationC. They can be separated by homogenizationD. It is more likely that they would be separated by differential centrifugation than by density centrifugationE. They can’t be separated at all because they have the same densities4. The first 15-20 amino acids of a nascent peptide on soluble, cytoplasmic, eukaryotic polysomes are most like to be needed to determine each of the following except:A. Whether the mature protein will remain in the cytoplasmB. Whether the mature protein will go to the nucleusC. Whether the mature protein will end up inside the mitochondriaD. Whether the translation will be completed in the cytoplasm or be directed to continue on RERE. Whether an integral membrane protein is a spanning protein or not5. Which of the following could be part of RER membranes but not golgi membranes?A. Transmembrane cargo receptorsB. SRP receptorsC. Integral membrane proteinsD. COPIE. Glycolipids16. A nascent protein in the RER that is destined to be a soluble enzyme inside of lysosomes should have:A. No NLS, signal sequence or stop transfer sequence, just a mannose-6-phosphateB. A low pH optimum and clathrin on the outside of the vesicle as it leaves the RERC. Problems getting there because it should be made on free polysomes, not on RERD. A signal sequence and the ability to accept a mannose-6-phosphate modification but no NLS or stop transfer sequencesE. An LLS (lysosome localization sequence) but no stop transfer sequence or signal sequence7. Which of the following is most likely to be made by co-translational translocation?A. A soluble, prokaryotic enzymeB. A soluble enzyme secreted from a eukaryotic cellC. TubulinD. HistonesE. Condensin8. The role of the translocon in RER protein synthesis is:A. To move the ribosomes along the mRNA so that translation can continue aftera pause.B. To bind to the SRP/mRNA complex and anchor the translation machinery on the RERC. To provide a channel in the membrane for the nascent polypeptide to pass throughD. To move the polysomes from the cytoplasm to the RERE. To move the core complex carbohydrate onto the protein 9. The core complex carbohydrate that is attached to proteins to make glycoproteins canface any of the following aqueous areas except:A. The outside of the cellB. The lumen of VTCs (vesicular tubular clusters)C. The cytoplasmic side of the RERD. The lumen of the medial golgiE. The lumen of the RER10. In the radioactive amino acid metabolic labeling experiments with pancreatic cells, the reason that the curve for the golgi vesicles is transient over time (goes up and then comes down) is:A. The secreted proteins don’t go through the golgiB. When the pulse of radioactive proteins arrived in the golgi it increased the amount of autoradiographic grains exposed but the chase made it decreaseC. The volume of the golgi is so much less than that of the RER that the radioactivity was dilutedD. The radioactivity went up because proteins were moving into the golgi but then it went down because of the exponential radioactive decay of the labelE. The autoradiographic exposure hit its maximum and bleached the film211. Do soluble proteins that are destined for secretion from pancreatic cells pass throughthe golgi after they are translated?A. No. Only membrane glycoproteins go to golgi for further glycosylationsB. No. They don’t pass through the endomembrane system because they are in vesiclesC. Yes, because that is where the enzymes are that cut them off of their membrane anchors to make them solubleD. No, because they are packaged for vesicular exocytosis in the SER.E. Yes, the radioactive amino acid pulse-chase experiments proved it12. Which of the following are seen primarily between the trans golgi and the plasma membranes?A. COPII vesiclesB. Vesicular tubular clustersC. ERGICD. Clathrin coated vesiclesE. Autophagosomes13. A transmembrane cargo receptor (like the ones described in BIO201B) can:A. Bind to both soluble cargo inside a vesicle and coat proteins B. Only bind soluble proteins on the inside of vesicles, not the outsideC. Bind to V-SNAREs but not to adapter proteins or COPIID. Be made in RER without a stop transfer sequenceE. Bind to cytoplasmic microtubules for intercellular transport14. The receptor part of mannose-6-phosphate receptors can face any of the following areas except:A. The lumen of the RERB. The outside of the cellC. The lumen of the lysosomeD. The cytoplasmE. The lumen of the trans golgi15. Receptor mediated endocytosis is:A. A way to degrade dead mitochondriaB. The process by which phagolysosomes are generatedC. The same thing as exocytosisD. A way to bring extracellular ligands into the cellE. Not dependent upon fusion with lysosomes16. In the original Meselson-Stahl experiments with bacterial DNA, they were first grown on 15N and then switched to 14N. If, instead, they were grown first on 14N and then switched to 15N for one generation:A. The experiment wouldn’t work because the radioactive DNA would kill the bacteriaB. The density of the DNA would be between (hybrid) the density expected for DNA that is all 14N and DNA