Bis 104 etzler Q - Page 1

Bis 104 etzler Q - Page 1 - Review Questions from Previous...

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Unformatted text preview: Review Questions from Previous Exams: Note: These questions provide examples of the types of quest ions asked in previous exams o f Dr. Etzler in this course. It is reco mmended that you first try to answer these questions on your own as you would do in the normal procedure. Note that the questions range in degree of difficult y. If you have trouble with the questions or wish to check your answers, the answers are provided in the Answers to Review Quest ions Sect ion on this web site. If you continue to have difficult y understanding them, your TA’s and Dr. Etzler are willing to go over them with you during their office hours or in a review session. 1. You are attempt ing to view a cell using a light microscope. The limit of resolut ion you can achieve using visible light of 550 nm wavelength is 0.6 mm. If you use the same lenses of this microscope in fluorescence microscopy using an ultravio let wavelength of 365 nm, will the reso lution be improved, made worse, or stay the same? Why? 2. Protein X is an integral membrane protein of the plasma membrane of pancreat ic cells. Previous experiments have established that the NH2­terminal end of this protein is exposed on the cytosolic side of the endoplasmic r eticulum. The protein has been found to have two transmembrane segments. On which side of the plasma membrane would you expect to find the COOH­terminal end of this protein? Why? 3. You have ant ibodies (called anti­PL) that can specifically recognize the head group of a phospho lipid that is present on the outer leaflet of the plasma membrane bilayer of a particular cell t ype. You also have antibodies (called ant i­X) that can specifically recognize an integral membrane protein (protein X) in the plasma membrane of the same cells. You prepare Fab fragments of both antibodies. You label the Fab fragments of anti­PL wit h a blue fluorescent dye. You label the fragments of anti­X with a yellow fluorescent dye. You then treat the above cells wit h both of the labeled Fab fragments and view them with a fluorescence microscope. You see a uniform green fluorescence covering the ent ire membrane surface. This fluorescence is due to the combination o f the blue and yellow dyes. You then proceed to use a laser to bleach a small patch in the membrane. You view this patch over a period of time and note any co lor changes that occur. For the purposes of this experiment you can assume that protein X is not anchored to the cytoskeleton. Describe any co lor changes you would expect to see by observing the bleached membrane patch with t ime. Briefly justify your answer. 4. It is possible to separate rough fro m smooth microsomes by sedimentation equilibrium centrifugation. Which fract ion, rough or smooth microsomes, would you expect to be closest to the bottom of the tube? Why? 5. Na+ K ATPase is a component of the erythrocyte membrane. Is this protein a + peripheral membrane protein or an integral membrane protein? De mo ...
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This note was uploaded on 05/24/2010 for the course BIS 104 taught by Professor Scholey during the Spring '08 term at UC Davis.

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