Exam 1 2006

Exam 1 2006 - Name _ Student number_ Bio 50 Cell and...

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Name ___________________________ Student number___________________________ Bio 50 Cell and Molecular Biology Exam I February 22, 2006 1. Put your name on the front page and your student number on all pages. 2. Write all your answers in the space provided. Do not use the back of pages. 3. Make sure you have all 8 pages and 10 questions . 4. Be concise and direct. Complete sentences are not necessary. 5. Diagrams are encouraged. 6. You have 3 hours to complete this exam. 7. Good luck to you! Mahhvelous membranes: (8 points total) Membranes are simply amazing and we would be goo without them. The plasma membrane, for example, has several different lipids asymmetrically distributed amongst its two membrane leaflets. This allows the cell to function in motility, and yet still compartmentalize well - the original cubical! a) Of the following molecules, which can diffuse freely across a lipid bilayer? Circle those that are freely diffusible across a membrane: Amino acids, ATP, Ethanol, ribosomes, oxygen, lipids, H + , pyruvate, transcription factors b) Name and draw the chemical structure of a lipid below. Describe the function of its key structural elements. Which part of the molecule functions as the great insulator of permeability? c) Animals that do not regulate their own temperature (cold-blooded, or ectothermic animals) are able to keep their membrane fluidity constant even in the face of changing temperatures. They do so by altering the molecular composition of their lipids. In the event of decreasing environmental temperatures , what 2 molecular changes in its membrane lipids might an animal make to keep its membrane fluidity constant (that is, as if it were a warmer temperature)? 1) 2) 1. 2 points 4 points 2 points
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Student number___________________________ 2 Transmembrane domains : (12 points total) Porin is an important protein in plant and animal cells. In plant cells it is in two different organelles, in animal cells it is in one organelle. First, describe what porin is, where porin is found specifically in a plant and an animal cell, and what its function is in a cell. What:
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This note was uploaded on 04/07/2008 for the course BIOL 50 taught by Professor Wiesel during the Spring '08 term at Brown.

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Exam 1 2006 - Name _ Student number_ Bio 50 Cell and...

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