Chapter 15 DVD questions PDF

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Essential Cell Biology, 3/e: Media DVD Quizzes Chapter 15 H: Eucaryotic Cells Contain a Basic Set of Membrane-enclosed Organelles N: 1 Q: The outer membrane of the nucleus is continuous with the membrane of which other organelle? A: A mitochondrion CA: The endoplasmic reticulum A: The Golgi apparatus A: A peroxisome N: 2 Q: Which organelle is the major site of new membrane synthesis in a cell? A: A mitochondrion CA: The endoplasmic reticulum A: The Golgi apparatus A: The nucleus N: 3 Q: Which organelle receives proteins and lipids from the endoplasmic reticulum, modifies them, and then dispatches them to other destinations in the cell? A: A mitochondrion A: An endosome CA: The Golgi apparatus A: The nucleus A: A peroxisome N: 4 Q: Which organelle is essentially a small sac of digestive enzymes that functions in degrading worn-out organelles, as well as macromolecules and particles taken into the cell by endocytosis? A: An endosome A: The Golgi apparatus CA: A lysosome A: The endoplasmic reticulum A: A peroxisome

N: 5 Q: Which organelle sorts ingested molecules and recycles some of them back to the plasma membrane? CA: An endosome A: The Golgi apparatus A: A lysosome A: The endoplasmic reticulum A: A peroxisome N: 6 Q: Which organelle contains enzymes used in a variety of oxidative reactions that break down lipids and destroy toxic molecules? A: A mitochondrion A: An endosome A: A lysosome A: The endoplasmic reticulum CA: A peroxisome N: 7 Q: Which of the following organelles is not surrounded by a double membrane? A: Mitochondrion A: Chloroplast CA: Golgi apparatus A: Nucleus H: Membrane-enclosed Organelles Evolved in Different Ways N: 8 Q: The interiors of the ER, Golgi apparatus, endosomes, and lysosomes communicate with each other in which of the following ways? CA: By small vesicles that bud off of one organelle and fuse with another A: By open pores that allow ions to exit and enter the organelles A: They do not communicate with one another. A: By excreting hormones and other small signaling molecules H: Proteins Are Imported into Organelles by Three Mechanisms N: 9 Q: Most mitochondrial and chloroplast proteins are made in which compartment of the cell? CA: In the cytosol A: In the endoplasmic reticulum A: Within the mitochondrion or chloroplast

N: 10 Q: Proteins that lack a sorting signal remain as permanent residents of which part of a eucaryotic cell? A: The nucleus CA: The cytosol A: The endoplasmic reticulum A: The Golgi apparatus A: A lysosome H: Signal Sequences Direct Proteins to the Correct Compartment N: 11 Q: If a signal sequence is removed from an ER protein: CA: the protein remains in the cytosol. A: the protein will enter an organelle other than the ER. A: the protein will be immediately degraded. A: the protein will be exported from the cell. H: Proteins Enter the Nucleus Through Nuclear Pores N: 12 Q: Proteins have to unfold during their transport across the membranes of all but one of the following organelles. Which one? CA: The nucleus A: Mitochondria A: Chloroplasts A: The endoplasmic reticulum N: 13 Q: Which proteins bind to nuclear localization signals on newly synthesized proteins? A: Nuclear pore proteins CA: Nuclear transport receptors A: Signal-recognition particles H: Proteins Unfold to Enter Mitochondria and Chloroplasts N: 14 Q: Which of the following statements is NOT true of mitochondrial proteins that are synthesized in the cytosol? A: The proteins are unfolded as they are transported into the mitochondria. A: The proteins cross both the inner and outer mitochondrial membranes as they are imported. CA: The proteins are transported across the mitochondrial membranes while being synthesized. A: Chaperone proteins help draw the proteins inside the mitochondrion.

A: The proteins usually have a signal sequence at their N-terminus. H: Proteins Enter the Endoplasmic Reticulum While Being Synthesized N: 15 Q: Proteins in the cytosol that are destined for other organelles must first enter the: A: the nucleus. A: the Golgi apparatus. CA: the endoplasmic reticulum. A: the lysosomes. N: 16 Q: Which of the following is true? A: A special class of ribosomes embedded in the ER translates the proteins destined for that organelle. CA: A common pool of ribosomes is used to synthesize both the proteins that stay in the cytosol and those that are destined for the ER. A: All ribosomes are attached to the ER when they are synthesizing a protein. H: Soluble Proteins Are Released into the ER Lumen N: 17 Q: The ER signal sequence on a growing polypeptide chain is recognized by a signal recognition particle (SRP) in the cytosol. This interaction: A: causes the polypeptide chain to dissociate from the ribosome. A: causes the ribosome to return to the pool of free ribosomes in the cytosol. CA: guides the ribosome and its polypeptide to the ER membrane. A: speeds the synthesis of the polypeptide chain. H: Start and Stop Signals Determine the Arrangement of a Transmembrane Protein in the Lipid Bilayer N: 18 Q: In the process of translocating a polypeptide across the membrane of the endoplasmic reticulum, a stop transfer sequence halts the process. What eventually becomes of the stop transfer sequence? CA: It forms an α-helical membrane-spanning segment of the protein. A: It is cleaved from the protein. A: It is translocated into the lumen of the endoplasmic reticulum. H: Transport Vesicles Carry Soluble Proteins and Membrane Between Compartments N: 19 Q: The movement of materials from the plasma membrane, through endosomes, and then to lysosomes describes which type of pathway?

A: Secretory pathway CA: Endocytic pathway A: Exocytic pathway H: Vesicle Budding Is Driven by the Assembly of a Protein Coat N: 20 Q: What protein can assemble into a basket-like network that gives budding vesicles their shape? A: Dynamin CA: Clathrin A: Actin A: Myosin N: 21 Q: Vesicle budding is driven by the assembly of a protein coat. CA: True A: False H: Vesicle Docking Depends on Tethers and SNAREs N: 22 Q: Which proteins play a central role in the fusion of a vesicle with a target membrane? A: Rab proteins A: Tethering proteins A: Adaptin proteins A: Clathrin proteins CA: SNARE proteins N: 23 Q: Which molecule is displaced when a vesicle and its target membrane fuse? A: SNARES CA: Water A: Phospholipids A: Cholesterol A: Tethering proteins H: Most Proteins Are Covalently Modified in the ER N: 24 Q: Many proteins are glycosylated in: A: the cytosol. A: mitochondria. CA: the endoplasmic reticulum. A: lysosomes. A: peroxisomes.

N: 25 Q: Which of the following is NOT a role for the oligosaccharides on glycosylated proteins? A: They can protect the protein from degradation and hold it in the ER until it is properly folded. A: They can guide the protein to the appropriate organelle by serving as a transport signal for packaging the protein into appropriate transport vesicles. CA: They can provide a source of energy for the cell. A: When displayed on the cell surface, oligosaccharides form part of the cell’s carbohydrate layer and can function in the recognition of one cell by another. H: Exit from the ER Is Controlled to Ensure Protein Quality N: 26 Q: Which type of protein binds to improperly folded or improperly assembled proteins in the ER, holding them there until proper folding occurs? A: Tethering proteins A: Glycosylating proteins CA: Chaperone proteins A: Antibody proteins H: The Size of the ER Is Controlled by the Amount of Protein that Flows Through It N: 27 Q: In the unfolded protein response, the accumulation of misfolded proteins in the ER serves as a signal for the cell to do which of the following? A: Glycosylate the misfolded protein A: Increase the transport of misfolded proteins to the Golgi apparatus A: Export the misfolded proteins to the cytosol CA: Produce more ER H: Proteins Are Further Modified and Sorted in the Golgi Apparatus N: 28 Q: How do proteins travel from one cisterna to the next in the Golgi apparatus? CA: By transport vesicles that bud off from one cisterna and fuse with the next cisterna A: By physical connections between two cisternae A: Through pores in the membranes of cisternae N: 29 Q: Proteins entering the cis Golgi network can do which of the following? CA: They can either move onward through the Golgi stack or be returned to the ER.

A: They can either move backward through the Golgi stack or be sent to the plasma membrane. A: They are sorted according to whether they are destined for lysosomes or for the cell surface.

H: Secretory Proteins Are Released from the Cell by Exocytosis N: 30 Q: The constitutive exocytosis pathway of the Golgi apparatus operates continually in all eucaryotic cells. CA: True A: False N: 31 Q: What distinguishes proteins destined for regulated secretion? CA: They have special surface properties that cause them to form aggregates that are packaged into secretory vesicles. A: They have a series of amino acids that act as a tag that marks them for packaging into secretory vesicles. A: They are cleaved from membrane domains in the Golgi apparatus prior to being packed into secretory vesicles. H: Endocytic Pathways N: 32 Q: Cells ingest large particles by: A: pinocytosis. CA: phagocytosis. A: megacytosis. H: Fluid and Macromolecules Are Taken Up by Pinocytosis N: 33 Q: Eucaryotic cells continually ingest bits of their plasma membrane, along with small amounts of extracellular fluid. The lost pieces of membrane are replaced by the process of: A: pinocytosis. A: phagocytosis. CA: exocytosis. A: endocytosis. H: Receptor-mediated Endocytosis Provides a Specific Route into Animal Cells N: 34 Q: Which of the following is NOT true of receptor-mediated endocytosis? A: In receptor-mediated endocytosis, extracellular substances are internalized in clathrincoated vesicles. A: Low-density lipoproteins (LDLs) are taken into cells by receptor mediated endocytosis. A: Some viruses are taken into the cell by receptor-mediated endocytosis.

CA: In receptor-mediated endocytosis, internalized vesicles fuse with lysosomes, which then mature into endosomes. H: Endocytosed Macromolecules Are Sorted in Endosomes N: 35 Q: The low pH inside endosomes: A: destroys internalized cargo proteins. A: destroy internalized receptors. CA: causes internalized receptors to release their cargo. A: causes cargo proteins to bind to their receptors. N: 36 Q: Which cellular compartment acts as the main sorting station for extracellular cargo molecules taken up by endocytosis? A: Transport vesicles A: The Golgi apparatus CA: Endosomes A: Lysosomes H: Lysosomes Are the Principal Sites of Intracellular Digestion N: 37 Q: Which of the following is true of lysosomes? A: The products of digestion in lysosomes leave the lysosome by transport vesicles. A: Most of the lysosomal membrane proteins have glycosylated regions on the cytosolic side of the membrane. CA: Lysosomal enzymes are optimally active in the acidic conditions maintained within lysosomes. A: Lysosomes form from vesicles that pinch off from the endoplasmic reticulum. N: 38 Q: Which mechanism is used for degrading obsolete parts of a cell, such as a defective mitochondrion? A: Phagocytosis A: The unfolded protein response A: Apoptosis CA: Autophagy...