Test3%20Master pcb

Test3%20Master pcb - PCB3134 - Test 3 Spring, 2008 YOU WILL...

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PCB3134 - Test 3 Spring, 2008 YOU WILL BE AWARDED 2 BONUS POINTS ON THE EXAM IF YOU FOLLOW THESE DIRECTIONS DIRECTIONS 1. Enter your name and UFID number on your answer sheet, BOTH PRINTED & FILL IN THE BUBBLES. 2. Enter the five-digit test code number in slots 76-80 of your answer sheet. The test code can be found at the bottom of each page on your test. IT IS IMPORTANT THAT THIS IS DONE CORRECTLY OR YOUR TEST CANNOT BE GRADED !!! 3. Answer each question with the ONE BEST answer. 4. Turn in your answer sheet when you have finished. 5. KEEP YOUR TEST SO THAT YOU WILL HAVE THE TEST CODE NUMBER. Grades will be posted by test code numbers. --------------------------------------------------------------------------------------------------------------------------------- READ EACH QUESTION CAREFULLY . Select the BEST ANSWER. If you do not understand the question, you may ask the instructor for clarification. --------------------------------------------------------------------------------------------------------------------------------- 1. Endoplasmic reticulum proteins are normally retained in the endoplasmic reticulum following their synthesis. When a endoplasmic reticulum protein is transferred to another compartment of the cell's endomembrane system, what is its retrieval mechanism? (*) A membrane receptor recognizes and binds the amino acid sequence KDEL (lysine-aspartic acid- glutamic acid-leucine) located near the carboxyl end of the ER protein. (2) It is bound by a COPII protein in the membrane and transferred back to the ER. (3) A glucose residue is added to a mannose in the oligosaccharide attached to the protein so the protein can be bound by calnixin and packaged into a vesicle. (4) The proteins are collected into clathrin-coated vesicles which are transferred to the ER. 2. Phospholipids are made by integral endoplasmic reticulum membrane enzymes whose active sites face the cytosol and the phospholipids are inserted into the outer (cytoplasmic) leaflet of the ER membrane. How then do lipids destined for the inner (luminal) leaflet of the ER membrane get there? (*) There are enzymes called phospholipid translocators or flipases that can transfer these lipids into the opposite leaflet. (2) The phospholipids diffuse freely from the cytoplasmic leaflet into the luminal leaflet. (3) The phospholipids are disassembled on the cytoplasmic side and reassembled on the luminal side of the membrane. (4) The phospholipids are bound to dolicol phosphate and transferred from the luminal leaflet into the cytoplasmic leaflet. 3. What kind(s) of modifications are made in proteins as they move through the Golgi complex? a. Part of the protein's length may be trimmed by proteolytic enzymes. b.
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This test prep was uploaded on 04/20/2008 for the course PCB 3134 taught by Professor Multiple during the Spring '08 term at University of Florida.

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Test3%20Master pcb - PCB3134 - Test 3 Spring, 2008 YOU WILL...

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