Lodish 8e Ch04 Test Bank PDF

4-9 4 Culturing and Visualizing Cells Section 4.1 1. A myeloma cell is best described as: a. a precursor cell that gives rise to gametes. b. an immortal immune cell that cannot produc...

4-9 4 Culturing and Visualizing Cells Section 4.1 1. A myeloma cell is best described as: a. a precursor cell that gives rise to gametes. b. an immortal immune cell that cannot produce antibodies. c. a self-renewing stem cell. d. The first and third answers are correct. Ans: b Question Type: Multiple Choice Chapter: 4 Blooms: Remembering Difficulty: Easy 2. What factors necessary for growth of animal cells in culture are provided by serum? a. amino acids b. precursors of DNA synthesis c. growth factors d. vitamins Ans: c Question Type: Multiple Choice Chapter: 4 Blooms: Remembering Difficulty: Easy 3. Which one of the following is the best technique/approach to allow you to localize catalase in peroxisomes? a. a catalase monoclonal antibody and transmission electron microscopy b. platinum or gold and scanning electron microscopy c. FRAP and FRET d. all of the above Ans: a Question Type: Multiple Choice Chapter: 4 Application Difficulty: Moderate 4. All of the following are produced by animal cells in culture and help the cells adhere to the culture dish EXCEPT: a. glycoproteins. b. collagen. c. phospholipase A. d. hyaluronic acid. Ans: c Question Type: Multiple Choice Chapter: 4 Blooms: Remembering Difficulty: Moderate 5. Characteristics of transformed cells can include all of the following EXCEPT: a. aneuploidy. b. ability to differentiate into different cell types. c. tight junctions. d. presence of integrated viral genes. Ans: c Question Type: Multiple Choice Chapter: 4 Blooms: Remembering Difficulty: Easy 6. Separation of most blood cells is difficult, if not impossible, to achieve because they have similar properties and/or densities. What procedure is used to separate T-cells of the immune system from the many other different types of white blood cells or spleen cells? What feature of the T-cell facilitates the isolation protocol? Ans: Flow cytometry and fluorescence-activated cell sorting is used to select and isolate T cells from numerous other cell types. Briefly, T cells, unlike other cells, express CD3 and Thy1.2 proteins on their cell surface. Antibodies specific to these markers are linked to a fluorescent dye and incubated with the pool of cells. The antibodies bind the cell-surface markers on the T-cell surface, and when all cells are placed in the FACS machine, a laser is used to excite the dye, causing it to fluoresce. Fluorescing T cells selectively sorted from the non- fluorescing cells can be cultured in vitro. Question Type: Essay Chapter: 4 Application Difficulty: Moderate 7. The purpose of treating tissue from an embryonic chick with trypsin and EDTA when generating a primary cell culture is to: a. break down proteins present in the serum so the cells can use the amino acids for energy. b. cleave any cell surface proteins so you can grow the chick cells as a suspension culture for Difficulty: Easy use in an experiment. c. break the protein–protein interactions that hold cells together in a tissue. d. prevent cell senescence. Ans: c Question Type: Multiple Choice Chapter: 4 Blooms: Understanding Difficulty: Moderate 8. Primary cultures contain _____ (this cell type) which quickly predominate over the other cell types. Given the proper space and nutrients needed to grow, these cells can divide about 50 times, such that after 50 doublings, an original culture of 100 cells would become _____ cells. a. fibroblasts; 2500 17 b. fibroblasts; 1.1 × 10 c. epithelial cells; 2500 15 d. epithelial cells; 4.5 × 10 Ans: b Question Type: Multiple Choice Chapter: 4 Blooms: Analyzing Difficulty: Moderate 9. In your cell biology laboratory class, you are given a sample of blood. Which of the following results are NOT possible from your analysis of this blood using flow cytometry? a. isolation of the largest and most dense cells from the smaller blood cells b. measurement of the amount of DNA in white blood cells c. relative quantitation of the sizes and shapes of the cells in the blood sample d. after the addition of fluorescent antibodies specific to T cells, the analysis of T cell abundance and size relative to other cells in the sample Ans: a Question Type: Multiple Choice Chapter: 4 Application Difficulty: Moderate 10. Epithelial cells have distinct surfaces. Which of these surfaces tends to be involved in secreting proteins out of the cell and into the bloodstream? a. apical b. basal c. lateral d. all of the above Ans: a Question Type: Multiple Choice Chapter: 4 Blooms: Remembering Difficulty: Easy 11. When studying a new protein, it is useful to generate an antibody against it to tag it in experiments designed to study its function and localization. Which of the following is NOT a step needed to generate this new antibody? a. Mouse spleen cells are fused with myeloma cells. b. Cells are selected for their ability to divide and grow in the absence of purines in the medium. c. Mice are injected with the antibody that will tag the new protein. d. The spleen is isolated from a laboratory mouse. Ans: c Question Type: Multiple Choice Chapter: 4 Blooms: Understanding Difficulty: Easy 12. Why are cells cultured in the lab such a useful model system for studying human disease? a. Cells only function when they are not organized into tissues. b. Humans are a varied population and extrapolating from physiological studies yields mixed results. c. Cells cultured in the lab behave exactly the same as cells in the human body. d. Cells are very inexpensive to grow. Ans: b Question Type: Multiple Choice Chapter: 4 Application Difficulty: Difficult 13. Drugs used to inhibit which molecules would reduce the amount of antibody produced by hybridomas? a. proteasome inhibitors b. protease inhibitors c. transcription inhibitors d. antibiotics Ans: c Question Type: Multiple Choice Chapter: 4 Application Difficulty: Difficult Section 4.2 14. The phenomenon in which a chemical absorbs light at one wavelength and emits it at a specific and longer wavelength is called: a. differential interference contrast. b. fluorescence. c. deconvolution. d. shadowing. Ans: b Question Type: Multiple Choice Chapter: 4 Blooms: Understanding Difficulty: Easy 15. Which of the following could be used to visualize subcellular structure in living cells? a. transmission electron microscopy b. scanning electron microscopy c. bright-field microscopy d. differential interference light microscopy Ans: d Question Type: Multiple Choice Chapter: 4 Blooms: Understanding Difficulty: Easy 16. To visualize cells by immunofluorescence microscopy, the cells must be: a. placed in a vacuum. b. living. c. sectioned. d. permeabilized. Ans: d Question Type: Multiple Choice Chapter: 4 Blooms: Understanding Difficulty: Moderate 17. The fluorescent properties of dyes such as SNARF-1 can provide information on the: a. location of specific proteins. + b. concentration of H ions in specific regions of the cell. c. the amount of RNA in a cell. d. volume of a cell. Ans: b Question Type: Multiple Choice Chapter: 4 Blooms: Understanding Difficulty: Easy 18. How does the wavelength of the light used to illuminate a specimen affect the ability to resolve objects within the specimen? l Ans: Because the limit of resolution is given by D = (0.61 /(N sin a), shorter wavelength light (e.g., blue) will provide better resolution than longer wavelength light (e.g., red). Question Type: Essay Chapter: 4 Blooms: Understanding Difficulty: Moderate 19. Fixatives such as formaldehyde are routinely used in certain types of electron microscopy and light microscopy. However, fixatives may introduce complications in the analysis of the resulting images. What problems may result from using fixatives? Ans: Most fixatives are cross-linking agents that immobilize proteins and other cellular molecules. As part of the fixation process, samples are often also dehydrated. Such chemical changes may alter the normal structure and spatial relationship of cellular components, and this must be taken into account when interpreting images of fixed specimens. Question Type: Essay Chapter: 4 Blooms: Analyzing Difficulty: Moderate 20. Which of the following allows one to circumvent the theoretical resolution of the microscope? a. total internal reflection fluorescence microcopy b. photo-activated localization microscopy c. indirect immunofluorescence microscopy d. double-label fluorescence microscopy Ans: b Question Type: Multiple Choice Chapter: 4 Blooms: Understanding Difficulty: Moderate 21. A small tumor is excised from a patient’s body. The pathologist wants to examine the number, size, and arrangement of cells within the tumor. The best technique to use would be: a. DIC microscopy. b. phase contrast microscopy. c. bright-field microscopy after fixation, sectioning, and staining. d. fluorescence microscopy. Ans: c Question Type: Multiple Choice Chapter: 4 Blooms: Understanding Difficulty: Moderate 22. Fluorescence microscopy of cells that are labeled with a green fluorescent antibody against microtubules (a cytoskeletal component) differs from cells expressing green fluorescent protein (GFP) tagged to beta tubulin (a component of microtubules) in all the following ways EXCEPT: a. the antibody labeled cells need to be permeabilized before visualization, while the GFP cells do not. b. the microtubules could change their localization over time in the GFP cells, but not in the antibody labeled cells. c. the GFP cells do not need to be treated with fixatives, but the antibody labeled cells do. d. the antibody labeled cells will identify the microtubule structures, while the GFP will be observed in other places in the cell because it is not as specific as an antibody. Ans: d Question Type: Multiple Choice Chapter: 4 Application Difficulty: Difficult 23. Fluorescence microscopy of intact organisms or large cells results in the generation of blurred images. Which of the following is NOT a technique that reduces the out-of-focus signal that causes blurring? a. two-photon excitation microscopy b. confocal microscopy c. fluorescence recovery after photobleaching (FRAP) d. deconvolution microscopy Ans: c Question Type: Multiple Choice Chapter: 4 Blooms: Remembering Difficulty: Easy Section 4.3 24. Describe how a Förster resonance energy-transfer (FRET) biosensor like cameleon, which consists of CFP linked to YFP by the protein calmodulin, can detect local changes in calcium ion concentration. For your information, CFP excites at 440 nm and emits at 480 nm, whereas YFP emits at 535 nm. Ans: Basically, if calcium is absent and the cameleon construct is excited by UV light at 440 nm, there is emission of energy at 480 nm, but because the distance between CFP and YFP is greater than 10 nm, the energy cannot be transferred to YFP and hence there is no detection of light at 535 nm. In the presence of calcium ions, however, calmodulin undergoes a conformational change, which brings CFP in close proximity to YFP. When CFP is excited with UV light at 440 nm, the energy is transferred to YFP, allowing it to fluoresce and be detected at 535 nm. Question Type: Essay Chapter: 4 Blooms: Analyzing Hard 25. Osmium tetroxide is commonly used to: a. stain specimens for light microscopy. b. coat specimens for metal shadowing electron microscopy. c. stain specimens for transmission electron microscopy. 2+ d. measure the Ca concentration inside living cells. Ans: c Question Type: Multiple Choice Chapter: 4 Blooms: Understanding Difficulty: Easy 26. You are studying lamins and use an antibody method to follow their expression and subcellular localization at the electron microscope level. What process would you use to find these proteins in the bacteria E. coli? Ans: Normally, antibody labeling can be used in tandem with electron microscopy to visualize proteins in thin sections. Cells are lightly fixed to avoid denaturing the epitopes on the desired protein and, after freezing, the tissue is sectioned at very low temperature. The tissue is thawed and a specific antibody to the desired protein is applied as in immunofluorescence microscopy. To detect the antibody, however, the tissue is incubated with electron-dense gold particles attached to protein A, a bacterial protein that binds the Fc segment of all antibodies. These gold particles are seen at the level of the electron microscope; however, you would not be able to see lamins in E. coli because bacteria do not contain membrane-bounded organelles and lamins are a component of the nuclear envelope. Question Type: Essay Chapter: 4 Application Hard 27. The best 3-D images of cellular organelles come from: a. cryoelectron microscopy. b. immunoelectron microscopy. c. thin-section electron microscopy. d. low-angle rotary shadowing with TEM. Ans: a Question Type: Multiple Choice Chapter: 4 Blooms: Remembering Difficulty: Moderate Section 4.4 28. If a cellular homogenate were subjected to differential centrifugation, which of the following would be expected to pellet first? a. the endoplasmic reticulum b. mitochondria c. the cytosol d. nuclei Ans: d Question Type: Multiple Choice Chapter: 4 Application Difficulty: Moderate 29. The disruption of a cell is necessary to release its organelles and contents for subsequent isolation. One method, called _____, uses ultrahigh-frequency sound to disrupt the cell plasma membrane. a. tomography b. epitope tagging c. sonication d. centrifugation Ans: c Question Type: Multiple Choice Chapter: 4 Blooms: Remembering Difficulty: Easy 30. Although many types of vesicles are similar in size and density, it is possible to isolate specific types of vesicles through the use of: a. a fluorescent-activated cell sorting machine. b. antibodies attached to bacterial carriers and low speed centrifugation. c. ultracentrifugation. d. light microscopy. Ans: b Question Type: Multiple Choice Chapter: 4 Blooms: Understanding Difficulty: Easy 31. Ultracentrifuges allow cell biologists to isolate mitochondria from lysosomes based on organelle differences in: a. isoelectric point. b. ionic composition. c. equilibrium density. d. size. Ans: c Question Type: Multiple Choice Chapter: 4 Application Difficulty: Moderate 32. Rough endoplasmic reticulum can be separated from smooth endoplasmic reticulum by differential centrifugation. What is the basis for this fractionation? Ans: During cell disruption, the endoplasmic reticulum fragments and reseals into small vesicle-like compartments termed microsomes. Microsomes derived from the rough endoplasmic reticulum contain ribosomes and these ribosomes provide additional mass, which allows separation from microsomes derived from the smooth endoplasmic reticulum. Question Type: Essay Chapter: 4 Blooms: Understanding Difficulty: Moderate 33. The enzymatic functions of specific organelles can best be examined: a. in intact cells where the organelles are working as they normally would. b. in cells that have been prepared for SEM (scanning electron microscopy). c. in fractions taken from cell homogenates that have been separated by differential centrifugation. d. in fractions taken from differential centrifugation of cellular homogenates that are further incubated with antibodies specific to the organelle under study, which can be used to precipitate the organelles away from contaminates. Ans: d Question Type: Multiple Choice Chapter: 4 Blooms: Understanding Difficulty: Moderate 34. Centrifugation of homogenized tissue from a mouse liver at 15,000 × g for 5 minutes will pellet: a. mitochondria b. nuclei c. plasma membrane d. mitochondria and nuclei Ans: d Question Type: Multiple Choice Chapter: 4 Blooms: Remembering Difficulty: Easy 35. Rank the following organelles in terms of most dense to least dense: I. mitochondria II. peroxisomes III. lysosomes a. I, II, III b. II, I, III c. III, II, I d. III, I, II Ans: b Question Type: Multiple Choice Chapter: 4 Blooms: Remembering Difficulty: Moderate 36. Proteomic studies allow for the identification of all proteins within an organelle, assuming the organelle can be purified sufficiently well. Proteomic analyses of mitochondria from different cell types revealed what interesting finding? a. Mitochondrial proteins have all been identified over the years. b. Mitochondria contain less than 40 different proteins. c. Mitochondria in different cell types can contain different proteins. d. Mitochondrial proteins cannot be examined using proteomic approaches. Ans: c Question Type: Multiple Choice Chapter: 4 Blooms: Remembering Difficulty: Moderate