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BIOL 1000A F2013 test 2 - version B -.pdf

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Department
Biology
Course
BIOL 1000
Professor
Paula Wilson
Semester
Fall

Description
Biol1000 Fall 2013 – Test 2   BIOL  1000  3.0  Section  A   Test  2  November  8,  2013     This  ENTIRE  test  package  and  scantron  MUST  be  submitted  to  receive  a  grade     Your  STUDENT  NUMBER  and  NAME  must  be  clearly  indicated  on  this  package  and   scantron  sheet  to  receive  a  grade     Your  STUDENT  NUMBER  must  also  be  BUBBLED  CORRECTLY  in  the  scantron  sheet   to  receive  a  grade     There  are  35  Multiple  Choice  Questions  (1  mark  each).    Choose  the  BEST  answer   for  each  question.       ELECTRONIC  AIDS  (e.g.  calculators,  phones  iPods  etc.)  are  NOT  PERMITTED.     ONLY  THE  SCANTRON  WILL  BE  GRADED  SO  MAKE  SURE  YOU  FILL  IN  THE   ANSWER  TO  EACH  QUESTION  ON  THE  SCANTRON  BEFORE  THE  ALLOTTED  TIME   FOR  THE  TEST  IS  UP.     YOU  WILL NOT  BE  PROVIDED  EXTRA  TIME  TO  DO  SO.   HAND  IN  QUESTION  BOOKLET  WITH  SCANTRON.     If  you  finish  the  test  before  the  allotted  time  then  please  raise  your  hand  and  an   invigilator  will  come  and  collect  your  test   GOOD  LUCK!!!!   Last name: Section First name: Student number: A Page 1 of 11 Biol1000 Fall 2013 – Test 2 1. How does the fluid mosaic model fit our understanding of membrane structure? A. Fluid mosaic refers to the different types of lipid within the membrane and the tendency for the membrane to melt given a high enough temperature. B. The fluid refers to the ability of lipid to move freely within a flexible membrane and mosaic refers the presence of a variety of different types of protein and other components within the membrane. C. The fluid refers to the presence of water surrounding the membrane and mosaic refers to the presence of both saturated and unsaturated fats. D. The fluid refers to the ability of ions and other molecules to flow across the membrane and mosaic refers to the diversity of molecules that can cross. 2. Which of the following statements about membrane structure is true? A. Cholesterol molecules extend across the lipid bilayer, so that their charged ends can interact with water. B. Glycolipids are only found on the cytoplasmic side. C. Lipids move readily within one side of the bilayer, but rarely flip from one side to the other. D. Peripheral proteins are usually found only on the cell surface, not the cytoplasmic side of the membrane. 3. You are a scientist and are studying the plasma membrane of bacteria. You leave the bacteria growing in a water bath overnight at 23 C but the electricity goes out after you leave and the temperature drops to 15 C . When you get back several hours later, what will you expect to see when you analyze the bacterial membrane? A. The loss of sterols from the membrane. B. Lower levels of saturated fats. C. Higher levels of saturated fats. D. Higher levels of trans fats. 4. Which of the following molecules is likely to move most quickly across the membrane by simple diffusion and why? A. O -ecause it is non polar B. Cl because it is negatively charged. C. Na because it is small. D. Glucose because it is polar E. There would be no difference in the rate of diffusion across the membrane for these molecules. Page 2 of 11 Biol1000 Fall 2013 – Test 2 5. Side A of a membrane contains 0.05 µM of sodium. Side B of this membrane contains 0.05 µM of sodium. Diffusion of sodium across the membrane occurs via an open channel. Based on this information predict the direction of movement of sodium. A. Sodium will move from Side A to Side B B. Sodium will move from Side B to Side A C. There will be no movement of sodium across the membrane. D. Sodium will move in both directions at equal rates. 6. You are working with two artificial membranes in the lab. They are both identical in terms of lipid content except that lipid A has three times more cholesterol content than lipid B. As you increase the temperature, which of the two will melt first? A. Lipid A will melt first as the cholesterol will tend to prevent the fatty acid tails from aligning and packing tightly. B. Lipid A will melt first as the cholesterol will align with the unsaturated fats but not the saturated fats. C. Lipid A will melt last as the cholesterol will interact with the fatty acid tails and restrict phospholipid movement. D. Lipid A and Lipid B will melt at about the same temperature as cholesterol content does not affect membrane fluidity. 7. A cell is placed in a solution of growth medium that has a solute concentration of 3.0 mM. The internal solute concentration of the cell is 0.2 mM. Which of the following statements is true? A. The growth medium is hypertonic compared to the cytoplasm and the cell will shrink. B. The growth medium is hypotonic compared to the cytoplasm and the cell will swell. C. The growth medium is isotonic compared to the cytoplasm and the cell will shrink. D. The growth medium is hypertonic compared to the cytoplasm and the cell will swell. E. None of the above. 8. Which of the following includes all others presented below? A. Osmosis B. Passive Transport C. Facilitated Diffusion D. Movement of a solute through a channel protein. Page 3 of 11 Biol1000 Fall 2013 – Test 2 9. Through the process of endocytosis, some cells internalize (engulf) about 100% of their plasma membrane in approximately 30 minutes. The cell surface to volume ratio of these cells never change. How is this possible? A. The plasma membrane is not included in cell surface to volume measurements. B. Exocytosis replaces the internalized plasma membrane at a rate equal to membrane removal. C. Phospholipids are removed from the plasma membrane to maintain surface area to volume ratios. D. Expansion of the endomembrane area, due to fusing of endocytotic vesicles, makes up for the reduction in plasma membrane surface area. + 10. Lactose is moved into E. coli using a H /lactos+ symporter. Based on your knowledge of symporters, what is the role of H ? A. It is moving into the cell against its concentration gradient. B. It is binding to the transport protein to open the gated lactose channel. C. It is moving out of the cell against its concentration gradient. D. It is moving into the cell along its concentration gradient. E. It is binding to lactose and changing its conformation. The lactose/H + complex then binds the receptor site on the transport protein. 11. In question #10 above, what type of transport is this? A. primary active transport B. secondary active transport C. facilitated diffusion D. transport via a gated ion channel 12. Some viruses inject their DNA into cells, but others are taken in whole by cells. How are they likely to be transported into the cell? A. endocytosis B. exocytosis C. active transport D. pinocytosis Page 4 of 11 Biol1000 Fall 2013 – Test 2 13. You are studying the movement of solute X across a cell membrane and want to know how it is moving across. You run an experiment measuring the rate of movement (called diffusion rate in the graph) at different concentration gradients of solute X across the membrane. You obtain the following curve: What is the best conclusion given these data? A. The solute is crossing by simple diffusion. B. The solute is crossing by facilitated diffusion. C. The solute could be crossing by simple or facilitated diffusion. D. The solute must be using active transport. 14. Is the follo
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