TEST BANK – BECKER’S WORLD OF THE CELL

TEST BANK – BECKER’S WORLD OF THE CELL Smooth ER is responsible for all of these functions EXCEPT __________. A. steroid synthesis B. protein synthesis C. drug detoxification D. hydroxylation reactions - CORRECT ANSWER-B. protein synthesis Which of the following statements about autophagy is FALSE? A. Lysosomes are involved in the process of autophagy. B. Macrophagy involves the formation of a vacuole surrounded by a single phospholipid bilayer. C. Old organelles can be destroyed by macrophagy. D. Cells that undergo starvation demonstrate an increase in autophagy. - CORRECT ANSWER-B. Macrophagy involves the formation of a vacuole surrounded by a single phospholipid bilayer. Which of the following experimental treatments would NOT compromise the ability of a liver cell culture to metabolize and detoxify a nonpolar drug? A. administration of specific inhibitors for cytochromes P-450 B. disruption of smooth ER structure and function C. depletion of cellular NADH/NADPH D. disruption of lysosomal structure and function - CORRECT ANSWER-D. disruption of lysosomal structure and function A novel and highly virulent virus is discovered that promotes cell death by producing a protein toxin that inhibits the folding of newly synthesized glycoproteins. Which of the following would NOT be a target for this viral protein? A. calreticulin B. flippase C. UGGT D. calnexin - CORRECT ANSWER-B. flippase Sugars (mannose, sialic acid, glucose, and N-acetylglucosamine) that compose the oligosaccharide of glycoproteins are added sequentially to dolichol phosphate on the ER membrane in the initial steps of protein glycosylation. What is the purpose of conjugating the sugars to UDP prior to their addition to the growing oligosaccharide chain? A. Conjugating UDP to the sugar activates it for reaction. B. UDP prevents the sugars from being metabolized by glycolysis in the ER. C. UDP is toxic to the ER, and conjugating it to the sugar detoxifies the UDP. D. The UDP sugar is smaller than the isolated sugar, making it easier to add to the growing oligosaccharide. - CORRECT ANSWER-A. Conjugating UDP to the sugar activates it for reaction. Which of these events is NOT involved in exocytosis? A. internalization of cell surface receptors B. phagosome formation C. a transient increase in intracellular Ca2+ D. activity of a second messenger - CORRECT ANSWER-B. phagosome formation The term flippase __________. A. describes the class of enzymes that mix the phospholipids during vesicle fusion as the vesicle flips inside out B. refers to the class of enzymes that rearrange the sugars on oligosaccharides C. refers to the protein that regulates the assembly and disassembly of clathrin-coated vesicles D. describes two kinds of enzymes: One moves an oligosaccharide carrier, and the other moves phospholipids - CORRECT ANSWER-D. describes two kinds of enzymes: One moves an oligosaccharide carrier, and the other moves phospholipids Endosomes are formed from __________. Endosomes differ from lysosomes in that they have __________ and inactive __________. A. rough ER; two membranes; ribosomes B. the plasma membrane; lower pH; KDEL receptors C. LDL particles; neutral pH; clathrin D. the Golgi complex; higher pH; acid hydrolases - CORRECT ANSWER-D. the Golgi complex; higher pH; acid hydrolases v-SNARES and t-SNARES __________. A. are the first proteins that interact as a vesicle fuses with a target membrane B. interact with COP proteins C. are the only proteins that control the specificity of vesicle-target interactions D. bind to each other on their own but require cofactors to lock together and then release from each other - CORRECT ANSWER-D. bind to each other on their own but require cofactors to lock together and then release from each other Peroxins are __________ required for peroxisome __________. A. carbohydrates; energy production B. lipids; membranes C. enzymes; detoxification D. proteins; biogenesis - CORRECT ANSWER-D. proteins; biogenesis Which pairing of vesicle type with coat protein is correct? A. endosome/clathrin B. shuttle vesicle/COPII C. transition vesicle/clathrin D. secretory vesicle/COPI - CORRECT ANSWER-B. shuttle vesicle/COPII