213 Practice Exam 3 2017 S PDF

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BIOL 213, Spring 2017, Practice Exam 3

Choose the BEST answer to the following questions in 50 minutes or less: 1. Which of the following individuals are credited with developing early microscopy? a. Schleiden and Schwan b. Hooke and Leewenhoek c. Watson and Crick d. Washington and Hamilton e. Singer and Nicolson 2. Which of the following is a/are method(s) used to study subcellular structures and functions? a. transmission electron microscopy b. subcellular fractionation c. fluorescent microscopy d. A and B only e. All of the above 3. The surface area-to-volume ratio of a cell a. can be increased by increasing the volume of the cell. b. can be decreased by decreasing the surface area. c. explains why cells are small. d. is of little significance to maintaining cell homeostasis. e. none of the above 4. A prokaryotic cell does not have a _______ or _______. a. nucleus; membrane-bound organelles b. nucleus; DNA c. nucleus; ribosomes d. nucleus; membranes e. cell wall; membranes 5. Ribosomes are not visible under a light microscope, but they can be seen with an electron microscope because a. electron beams have more energy than light beams. b. electron microscopes focus light with magnets. c. electron microscopes have more resolving power than light microscopes. d. electrons have such high energy that they pass through biological samples. e. living cells can be observed under the electron microscope. 6. Which of the following statements about the nuclear envelope is true? a. It contains pores for the passage of large molecules. b. It is composed of two membranes (a double membrane). c. It contains ribosomes on the inner surface. d. Both a and b e. All of the above

7. A cell has the following molecules and structures: enzymes, nuclear envelope, ribosomes, plasma membrane, peroxisomes, and mitochondria. It could be a cell from a. a bacterium. b. an animal, but not a plant. c. a plant, but not an animal. d. a plant or an animal. e. none of the above. 8. Which of the following structures or organelles is directly involved in autophagy? a. smooth endoplasmic reticulum b. mitochondria c. central vacuole d. lysosome e. glyoxysome 9. Which structure-function pair is mismatched? a. nucleolus; production of ribosomal subunits b. ribosome; protein synthesis c. nuclear lamina; DNA replication and nuclear structure d. Golgi; protein modification and sorting e. central vacule; intracellular transport 10. One difference between plant and animal cells is that a. only animal cells have mitochondria. b. only animal cells contain centrioles. c. plant cells only have a cell wall, whereas animal cells have a plasma membrane. d. plant cells lack a cytoskeleton. e. only plant cells have peroxisomes. 11. Chromatin is a series of entangled threads composed of a. microtubules. b. DNA and protein. c. fibrous proteins. d. cytoskeleton. e. membranes. 12. Which of the following is not a component of the endomembrane system? a. Rough endoplasmic reticulum b. Smooth endoplasmic reticulum c. Golgi apparatus d. Lysosomes e. Plastids 13. Cells that perform little protein synthesis but produce a large amount of lipids and sterols would have more… a. rough endoplasmic reticulum b. mitochondria. c. ribosomes. d. smooth endoplasmic reticulum e. lysosomes.

14. Lysosomes are important to eukaryotic cells because they contain a. photosynthetic pigments. b. starch molecules for energy storage. c. their own DNA molecules. d. the cells’ waste materials. e. digestive (hydrolytic) enzymes. 15. Components of chloroplasts include a. grana and thylakoids. b. chromatin and nucleoplasm. c. cristae and matrix. d. a trans region and a cis region. e. lysosomes and phagosomes. 16. An organelle/structure with an internal cross-section showing a characteristic “9 + 2” morphology or tubulin is the a. mitochondrion. b. vacuole. c. Golgi apparatus. d. flagellum. e. cytoskeleton. 17. The cytoplasm of adjacent plants cells are connected by? a. desmosomes. b. membrane-lined channels called plasmodesmata. c. the semirigid cell wall. d. gap junctions. e. an internal cytoskeleton. 18. The type of cell that always lacks a cell wall is the _______ cell. a. bacterial b. plant c. animal d. fungal e. prokaryotic 19. Which of the following is not an argument for the endosymbiotic theory of organelle evolution? a. Mitochondria and chloroplasts are about the same size as prokaryotic cells. b. Mitochondria and chloroplasts cannot be grown in culture, free of a host cell. c. Mitochondria and chloroplasts have DNA and ribosomes. d. Mitochondrial ribosomes synthesize proteins similar to those synthesized by bacterial ribosomes. e. Mitochondria and chloroplasts divide by binary fission, similar to most bacteria.

20. Centrifugation of a cell results in the rupture of the cell membrane and the compacting of the contents into a pellet in the bottom of the centrifuge tube. Bathing this pellet with a glucose solution yields metabolic activity, including the production of large amounts of ATP. One of the contents of this pellet is most likely which of the following? a. Cytosol b. Mitochondria c. Lysosomes d. Golgi bodies e. Thylakoids 21. A cell produces, modifies, and secretes a protein hormone. Which of the following are necessary for the cell to accomplish this? a. Rough endoplasmic reticulum b. Golgi c. Dynein/kinesin (molecular motors) d. Answers A and B are correct e. All of the above are correct 22. The extracellular matrix of animal cells a. holds cells together. b. contains collagen. c. contains proteoglycans. d. is involved in chemical signaling between cells. e. All of the above 23. An individual who is unable to produce one or more of the hydrolytic enzymes normally found in lysosomes could be described as having… a. Type II diabetes. b. Tay-Sachs disease. c. Multiple Sclerosis. d. Cancer. e. All of the above 24. Biological membranes are composed of a. nucleotides and nucleosides. b. enzymes, electron acceptors, and electron donors. c. fatty acids. d. monosaccharides. e. lipids, proteins, and carbohydrates. 25. Which of the following statements about cholesterol molecules is true? a. They are insoluble in hydrophobic membranes. b. They transport ions across membranes. c. They attach to carbohydrates. d. They disrupt membrane function. e. They alter the fluidity of the membrane.

For questions 26-29, match the labeled component of the cell membrane (Figure 1) with its description. 26. cholesterol 27. glycolipid 28. extracellular matrix 29. peripheral protein

30. The hydrophilic regions of a transmembrane (integral) protein are most likely to be found? a. only in muscle cell membranes. b. associated with the fatty acid region of the lipids. c. in the interior of the membrane. d. exposed on the surface of the membrane. e. either on the surface or inserted into the interior of the membrane. 31. The difference between tight junctions, desmosomes, and gap junctions is that a. desmosomes and gap junctions contain keratin, whereas tight junctions have collagen. b. gap junctions and tight junctions have specialized protein channels called connexons, whereas desmosomes do not. c. tight junctions and desmosomes have mechanical roles, whereas gap junctions facilitate communication between cells. d. desmosomes and gap junctions are found in epithelial tissue, whereas tight junctions are found in nerve cells. e. they all have different functions, even though their structure is the same. 32. Which of the following is an example of passive transport? a. Facilitated diffusion b. The sodium–potassium pump c. Phagocytosis d. Exocytosis e. Pinocytosis 33. One result of the movement of ions through ion channels is the creation of a membrane potential. The membrane potential is a. a charge imbalance across the plasma membrane. b. the difference in protein concentrations on either side of the plasma membrane. c. the difference in ATP concentrations on either side of the plasma membrane. d. a component of the extracellular matrix. e. the ability of macromolecules to recognize and adhere to one another.

34. For each molecule of ATP consumed during active transport of sodium and potassium, there is an import of _______ ion(s) and an export of _______ ion(s). a. two Na+; three K+ b. two Na+; one K+ c. one K+; three Na+ d. two K+; three Na+ e. three K+; two Na+ 35. A nonpolar molecule such as a steroid hormone usually binds to a a. cytoplasmic (intracellular) receptor. b. protein kinase. c. ion channel. d. phospholipid. e. second messenger. 36. Which of the following is false? a. Cells are bombarded with numerous signals, but they respond to only a few. b. A cell’s receptors determine whether or not the cell will respond to a signal. c. Receptor proteins are very specific. d. Cells usually only express one class or type of signal receptor proteins. e. Receptors usually undergo conformational change when bound to a signal/ligand 37. The insulin receptor is a protein (tyrosine) kinase receptor. Which of the following statements about the insulin receptor is false? a. It autophosphorylates. b. It requires binding by two insulin molecules to be activated. c. It catalyzes the phosphorylation of insulin response substrates. d. It is located entirely within the cytoplasm. e. None of the above 38. A benefit of the many steps involved in protein kinase cascades is that they allow for a. multiple signals to intersect. b. amplification of the signal. c. information to be communicated to multiple compartments within the cell. d. variation in the response from one cell type to another. e. all of the above 39. Which of the following does NOT happen when a ligand (signal) binds to a G-protein linked receptor? a. The receptor autophosphorylates. b. An associated G-protein complex is activated and dissociates c. GTP is hydrolyzed to GDP d. A primary signaling response could be produced/activated e. A secondary signaling response could be produced/activated 40. Which of the following adds/transfers phosphate groups to a protein substrate? a. Adenylyl cyclase b. Phosphatase c. Kinase d. Phosphodiesterase e. None of the above

Answer Key 1 B 2 E 3 C 4 A 5 C 6 D 7 D 8 D 9 E 10 B 11 B 12 E 13 D 14 E 15 A 16 D 17 B 18 C 19 B 20 B 21 E 22 E 23 B 24 E 25 E 26 E 27 B 28 A 29 D 30 D 31 C 32 A 33 A 34 D 35 A 36 D 37 D 38 E 39 A 40 C...