Cell Bio Exam Three

1. 1The plasma membrane is involved in which activities?

   1. AImport and export of nutrients and wastes
   2. BRNA interference
   3. CCell recognition
   4. DDNA replication and repair
   5. ECell signaling
   6. FCell growth and motility
2. 2Which characteristic describes the tails of phospholipids?

   1. AHydrophilic
   2. BStiff
   3. CCoated with sugars
   4. DHydrophobic
   5. EAmphipathic
3. 3Which term correctly describes the entire phospholipid molecule?

   1. AAmphipathic
   2. BHydrophobic
   3. CHydrophilic
   4. DHydropathic
   5. EApathic
4. 4Why do phospholipids form bilayers in water?

   1. AThe hydrophobic head is attracted to water, while the hydrophilic tail shuns water.
   2. BThe hydrophobic head shuns water, while the hydrophilic tail is attracted to water.
   3. CThe hydrophilic head is insoluble in water.
   4. DThe hydrophobic tail is attracted to water, while the hydrophilic head shuns water.
   5. EThe hydrophilic head is attracted to water, while the hydrophobic tail shuns water.
5. 5In a lipid bilayer, where do lipids rapidly diffuse?

   1. ABack and forth from one monolayer to the other in the bilayer
   2. BWithin the plane of their own monolayer
   3. CNot at all, because they remain in place within the bilayer
   4. DIn and out of the bilayer
   5. EWithin the plane of one monolayer and back and forth between the monolayers
6. 6Which of the following would produce the most fluid lipid bilayer?

   1. APhospholipids with tails of 20 carbon atoms and two double bonds
   2. BPhospholipids with fully saturated tails of 20 carbon atoms
   3. CLarge amounts of cholesterol
   4. DPhospholipids with tails of 18 carbon atoms and two double bonds
   5. EPhospholipids with fully saturated tails of 18 carbon atoms
7. 7How does the inclusion of cholesterol affect animal cell membranes?

   1. AIt tends to make the lipid bilayer less fluid.
   2. BIt makes the lipid bilayer more permeable.
   3. CIt has little effect on the properties of the lipid bilayer.
   4. DIt tends to make the lipid bilayer more fluid.
   5. EIt makes the lipid bilayer wider.
8. 8In eukaryotic cells, phospholipids are synthesized by enzymes bound to which of the following?

   1. AThe inside of the endoplasmic reticulum
   2. BThe cytosolic face of the Golgi apparatus
   3. CThe cytosolic face of the endoplasmic reticulum
   4. DThe cytosolic face of the plasma membrane
   5. EBoth monolayers of the endoplasmic reticulum
9. 9One of the grand challenges in biology is understanding how the first cells formed on Earth. Since all cells are bound by a cell membrane, origin of life researchers are interested in modeling what the first membranes may have been like. What types of molecules might these researchers consider to be the original building blocks of cell membranes?

   1. ACarbohydrate molecules
   2. BHydrophobic molecules
   3. CAmphipathic molecules
   4. DHydrophilic molecules
10. 10Which of the following would be most likely to disrupt lipid bilayer formation?

    1. AAddition of cholesterol to the membrane
    2. BAddition of a hydroxyl group to the head group of the lipid
    3. CAddition of a methyl group to the end of the lipid tail
    4. DAddition of a phosphate to the end of the lipid tail

11. 11Imagine you collected bacteria from the sediment in a frozen lake in Minnesota in January and compared the membranes to membranes from bacteria collected from a lake in Texas in June. Consider how the membranes would likely differ.
    
    The membranes in bacteria from the Minnesota lake would most likely have which of the following?

    1. AMore unsaturated lipid tails than membranes in Texas bacteria
    2. BFewer lipid tails with cis double bonds than membranes in Texas bacteria
    3. CMore saturated lipid tails than membranes in Texas bacteria
    4. DPhospholipids with more negatively charged phosphate groups than membranes in Texas bacteria
12. 12Which of the following is a function of proteins in the plasma membrane?

    1. Atransport molecules across the membrane
    2. Bgenerate the energy required for lipids to diffuse within the membrane
    3. Ctransmit extracellular signals to the cell interior
    4. Dallow specific ions to cross the plasma membrane, thereby controlling its electrical properties
    5. Eserve as anchors to attach the cell to the extracellular matrix
13. 13In the α helices of transmembrane proteins, the hydrophobic side chains face which direction?

    1. Athe cytosolic side of the membrane
    2. Bthe external or lumenal side of the membrane
    3. Cthe outside of the membrane-spanning helix
    4. Dthe inside of the membrane-spanning helix
14. 14Porin proteins—which form large, water-filled pores in mitochondrial and bacterial outer membranes—fold into β-barrel structures. The amino acids that face the outside of the barrel have what kind of side chains?

    1. AHydrophilic
    2. BPolar
    3. CCharged
    4. DHydrophobic
    5. EAmphipathic
15. 15The shape of a cell and the mechanical properties of its plasma membrane are determined by a meshwork of fibrous proteins called what?

    1. ATight junction
    2. BCell cortex
    3. CGlycocalyx
    4. DLamellipdoium
    5. EBasal lamina
16. 16On what side of the plasma membrane are the carbohydrate chains of glycoproteins, proteoglycans, and glycolipids located?

    1. ABoth sides
    2. BThe cytosolic side
    3. CThe extracellular side
    4. DThe underside
    5. EThe inside
17. 17How thick is the plasma membrane?

    1. A50 atoms
    2. B50 mm
    3. C50 nm
    4. D50 um
    5. E50 meters
18. 18What is a functionally specialized region of a cell membrane, typically characterized by the presence of specific proteins, called?

    1. ACell cortex
    2. BCarbohydrate layer
    3. CSpingomyelin domain
    4. DMembrane domain
    5. EGlycocalyx
19. 19Multipass transmembrane proteins can form pores across the lipid bilayer. The structure of one such channel is shown in the diagram. In this figure, what do the areas shown in red represent?

    

    1. Athe hydrophilic side chains of the transmembrane β barrel
    2. Bthe hydrophobic side chains of the transmembrane β barrel
    3. Cthe hydrophobic side chains of the transmembrane α helices
    4. Dthe amphipathic side chains of the transmembrane α helices
    5. Ethe hydrophobic lipid tails of the bilayer
    6. Fthe hydrophilic side chains of the transmembrane α helices
20. 20How does the cortex of a typical animal cell differ from that of a mature red blood cell?

    1. AIt gives the animal cell a distinctive biconcave shape.
    2. BIt allows the cell to move.
    3. CIt is richer in actin and in the motor protein myosin.
    4. DIt is simpler than that of a red blood cell.
    5. EIt allows the cell to selectively take up material from the environment.
21. 21Why would a cell express the aquaporin protein if water can cross the membrane in the absence of aquaporin?

    1. AAquaporin moves a positively charged ion along with water across the membrane.
    2. BAquaporin limits the movement of water molecules so they do not move too quickly across the membrane.
    3. CAquaporin facilitates the faster movement of water molecules across the membrane.
    4. DWater molecules cannot cross the membrane in the absence of a pore like aquaporin.
22. 22Which of the following characteristics of aquaporins ensure that the channel selectively transports only water molecules and not other solutes?

    1. AThe channel undergoes conformational changes to push water through the channel.
    2. BTwo asparagines in the center of the pore prevent protons from passing through the channel.
    3. CThe channel has a narrow pore that is only wide enough for a single water molecule to pass through.
    4. DA glutamate at the entrance to the channel prevents positive ions from entering the channel.
23. 23Lipid bilayers are highly impermeable to which molecule(s)?

    1. ANa+ and Cl–
    2. BOxygen
    3. CCarbon dioxide
    4. DSteroid hormones
    5. EWater
24. 24What is the voltage difference across a membrane of a cell called?

    1. APotential balance
    2. BElectrical current
    3. CGradient establishment
    4. DMembrane potential
25. 25The movement of an ion against its concentration gradient is called what?

    1. AFacilitated diffusion
    2. BOsmosis
    3. CPassive transport
    4. DActive transport
26. 26Which of the following mechanisms prevents osmotic swelling in plant cells?

    1. Athe collection of water in contractile vacuoles
    2. Bthe activity of Na+ pumps
    3. Cthe expulsion of water from contractile vacuoles
    4. Dtough cell walls
    5. Eturgor pressure
27. 27What determines the direction that glucose is transported across the membrane, through a glucose transporter?

    1. AA molecule's charge
    2. BA molecule's size
    3. CConcentration gradient
    4. DMembrane potential
28. 28Which of the following is supported by the information in the figure?

    

    1. AGlucose enters the cell by simple diffusion.
    2. BNucleotides enter the cell by facilitated diffusion.
    3. CSodium and potassium are involved in co-transport.
29. 29Glucose enters the cell by which process?

    

    1. AOsmosis
    2. BFacilitated diffusion
    3. CSimple diffusion
    4. DActive transport
30. 30Which organelle is important for controlling the concentration of calcium ions in the cytosol?

    1. AGolgi apparatus
    2. BLysosome
    3. CNucleus
    4. DEndoplasmic reticulum
31. 31Within the image of membrane transport proteins, identify the correct type of transport by dragging the labels to their targets.

    

    1. AUniport
    2. BSymport
    3. CAntiport
32. 32Which of the following characteristics of K+ channels are important for the selectivity for K+ rather than other ions?

    1. ABasic side chains line the wall of the pore.
    2. BAcidic side chains line the wall of the pore.
    3. CCarbonyl groups line the wall of the pore.
    4. DFour rigid protein loops line the narrowest part of the pore.
33. 33Ions in solution are found in a hydration shell of water. This shell must be removed for an ion to pass through the channel. How does the K+ channel accomplish removal of the water from the shell around the ion?

    1. AThe K+ channel uses the energy in ATP hydrolysis to remove the hydration shell from the K+ ion.
    2. BCarbonyl groups lining the wall of the pore can interact with the unsolvated K+ ion, balancing the energy needed to remove the hydration shell.
    3. CRigid protein loops strip the hydration shell from the potassium so that the ion is the right diameter to pass through the pore.
    4. DThe K+ channel has four subunits; one subunit removes the hydration shell as the ion passes through the pore formed by the three other subunits.
34. 34What is typically true of ion channels?

    1. AThey hydrolyze ATP.
    2. BThey are nonselective.
    3. CThey are open all the time.
    4. DThey operate by active transport.
    5. EThey are gated.
35. 35For voltage-gated channels, a change in the membrane potential has what effect on the channel?

    1. AIt changes which ions can pass through the channel.
    2. BIt changes the width of the channel opening.
    3. CIt alters the probability that the channel will be found in its open conformation.
    4. DIt either opens the channel or closes it, depending on the voltage.
    5. EIt makes the channel more sensitive to the binding of neurotransmitters.
36. 36In most animal cells, which ion can move through “leak” channels?

    1. AH+
    2. BCa2+
    3. CK+
    4. DCl-
    5. ENa+
37. 37To pass through the pore of an ion channel, what must be true of an ion?

    

    1. AIt must interact with polar groups in the narrowest part of the channel.
    2. BIt must be positively charged.
    3. CIt must surround itself with water molecules.
    4. DIt must avoid contact with the channel wall.
    5. EIt must interact with nonpolar groups in the selectivity filter.
38. 38During the activation of a neuron, the action potential propagates in only one direction. How is this achieved in the neuron?

    1. AThe Na+ channel remains open during the action potential and then rapidly returns to the closed state after the action potential passes.
    2. BThe Na+ channel becomes permanently inactivated after the action potential passes.
    3. CThe Na+ channel becomes inactivated and refractory to reopening for a short time after the action potential passes.
    4. DThe Na+ channel closes during the action potential and then rapidly returns to the open state after the action potential passes.
39. 39Tetrodotoxin is a potent toxin found in a variety of organisms including the pufferfish. The toxin binds to the extracellular side of the Na+ channel and prevents channel opening. This leads to paralysis of muscles, including the diaphragm. Death from respiratory failure can occur after ingestion of as little as 1 mg of the toxin. Why does this toxin cause paralysis?

    1. AThe axon membranes become over-depolarized.
    2. BThe Na+ channels remain in the inactive, refractory state.
    3. CThe membrane depolarization is not amplified along the axon.
    4. DThe Na+ channel does not open wide enough to allow enough Na+ through the channel.
40. 40When a neuron has been stimulated by a signal, the change in membrane potential first spreads locally to adjoining regions of the plasma membrane by what means?

    1. AOpening of ligand-gated ion channels
    2. BActive transport
    3. CAction potential
    4. DOpening of voltage-gated ion channels
    5. EPassive spread
41. 41What is the name of the specialized junction between a neuron and a target cell?

    1. ADendrite
    2. BSynapse
    3. CAxon
    4. DNerve terminal
    5. ESynaptic vesicle
42. 42Inhibitory neurotransmitters such as glycine and GABA make a postsynaptic cell harder to depolarize by allowing what?

    1. Aan influx of K+
    2. Ban influx of Na+
    3. Can influx of Cl–
    4. Dthe escape of Na+
43. 43Which is not true about the acetylcholine receptor on vertebrate muscle cells?

    1. AIt is a voltage-gated cation channel.
    2. BIts pore includes negatively charged amino acid side chains at both ends.
    3. CEven with acetylcholine bound, it flickers randomly between open and closed states.
    4. DIt depolarizes the muscle cell membrane when bound to acetylcholine.
    5. EIt does not discriminate between Na+, K+, and Ca2+.
44. 44Most of the energy released by oxidizing glucose is saved in the high-energy bonds of what molecules?

    1. AH20 and CO2
    2. BADP and other activated carriers
    3. CATP and other activated carriers
    4. DO2
    5. EGDP and other activated carriers
45. 45Useful energy is obtained by cells when sugars derived from food are broken down by which processes?

    1. Aglycolysis, the Calvin cycle, and oxidative phosphorylation
    2. Bglycolysis, the citric acid cycle, and oxidative phosphorylation
    3. Cgluconeogenesis, the citric acid cycle, and oxidative phosphorylation
    4. Dgluconeogenesis, fermentation, and oxidative phosphorylation
    5. Eglycolysis, the citric acid cycle, and gluconeogenesis
46. 46Where does the oxidative (oxygen-dependent) stage of the breakdown of food molecules occur in a eukaryotic cell?

    1. ACytosol
    2. BGolgi apparatus
    3. CMitochondria
    4. DEndoplasmic reticulum
47. 47Which of the following processes generates the largest number of ATP molecules?

    1. AElectron transport chain
    2. BGluconeogenesis
    3. CFermentation
    4. DCitric acid cycle
    5. EGlycolysis
48. 48Under anaerobic conditions, which metabolic pathway regenerates the supply of NAD+ needed for glycolysis?

    1. Aformation of acetyl CoA
    2. Bcitric acid cycle
    3. Cbreakdown of amino acids
    4. Dfermentation
    5. Ebreakdown of fats
49. 49Although the citric acid cycle itself does not use O2, it requires a functioning electron transport chain (which uses O2) in order to regenerate which molecule for further use in the citric acid cycle?

    1. AATP
    2. BNADH
    3. CFADH2
    4. DNAD+
    5. EADP
50. 50The NADH generated during glycolysis and the citric acid cycle feeds its high-energy electrons to which of the following?

    1. AFAD
    2. BThe electron transport chain
    3. CThe citric acid cycle
    4. DADP
    5. EH2O
51. 51In eukaryotic cells, what is the final electron acceptor in the electron transport chain?

    1. AATP
    2. BCO2
    3. CO2
    4. DFADH2
    5. ENAD+
52. 52In the electron transport chain, the oxygen atoms in O2 become part of which of the following molecules?

    1. AATP
    2. BH2O
    3. CNADH
    4. DCO2
    5. EGlucose (C6H12O6)
53. 53Which two-carbon molecule enters the citric acid cycle?

    1. Aoxaloacetate
    2. Bcarbon dioxide
    3. Cpyruvate
    4. Dacetyl CoA
    5. Ecitrate
54. 54What occurs in the first step of the citric acid cycle?

    1. ATwo molecules of acetyl CoA combine to form oxaloacetate.
    2. BCO2 is released.
    3. CATP is consumed.
    4. DNADH is produced.
    5. EA two-carbon molecule is combined with a four-carbon molecule to form citrate.
55. 55CO2 is released in which steps of the citric acid cycle, as shown below?

    

    1. ASteps 1 and 5
    2. BSteps 2 and 4
    3. CSteps 3 and 4
    4. DSteps 2, 3, and 4
    5. ESteps 1 and 8
56. 56The ethanol in wine and beer is produced from metabolic reactions carried out by the yeast Saccharomyces cerevisiae. Since it is of great commercial value, researchers have studied factors that influence ethanol production. To maximize ethanol yield, which environmental factor should be limiting?

    1. ASunlight
    2. BOxygen
    3. CGlucose
    4. DCarbon dioxide
57. 57How do enzymes maximize the energy harvested from the oxidation of food molecules?

    1. AThey allow the stepwise oxidation of food molecules, which releases energy in small amounts.
    2. BThey guarantee that each reaction involved in the oxidation of food molecules proceeds in just one direction.
    3. CThey allow a larger amount of energy to be released from food molecules such as glucose.
    4. DThey allow what would otherwise be an energetically unfavorable oxidation reaction to occur.
    5. EThey allow oxidation reactions to take place without an input of activation energy.
58. 58What happens to the energy captured during glycolysis and the citric acid cycle by the activated carriers NADH and FADH2.

    1. AIt is passed to an electron transport chain that uses it to oxidize food molecules.
    2. BIt is used to drive biosynthetic reactions.
    3. CIt is passed to an electron transport chain that uses it to generate a proton gradient across the inner mitochondrial membrane.
    4. DIt is passed to ADP to form ATP.
    5. EIt is passed to an electron transport chain that uses it to produce oxygen.
59. 59What does the term "gluconeogenesis" refer to?

    1. Athe synthesis of glucose from small organic molecules such as pyruvate
    2. Bthe breakdown of glucose during glycolysis
    3. Cthe breakdown of glucose during fermentation
    4. Dthe release of glucose from molecules such as glycogen
    5. Ethe transport of glucose across a cell membrane
60. 60When food is plentiful, animals can store glucose as what?

    1. Aglucose 6-phosphate
    2. Bacetyl CoA
    3. Cglycogen or starch
    4. Dglycogen
    5. Estarch
61. 61When nutrients are plentiful, plants can store glucose as what?

    1. Afats
    2. Bglucose 6-phosphate
    3. Cglycogen
    4. Dstarch
    5. Eglycogen and starch
62. 62In what form do plant and animal cells store fat?

    1. Atriacylglycerol
    2. Bnitroglycerin
    3. Cstarch
    4. Dglycogen
    5. Ephospholipids
63. 63You are packing for a hiking trip during which you’ll be burning a lot of calories with physical activity. You want to pack as efficiently as possible since you need to carry a tent and all your food. You can get the most calories out of 5kg of food if it is in the form [blank_start]of[blank_end]

    1. AStarch
    2. BFat
64. 64The outer membrane of the nucleus is continuous with the membrane of which other organelle?

    1. Aendoplasmic reticulum
    2. BGolgi apparatus
    3. Cperoxisome
    4. Dendosome
    5. Emitochondrion
65. 65Shown here is a drawing of a cell from the lining of the mammalian intestine. Label its organelles by dragging the labels on the right to the targets in the image.

    

    1. ATrue
    2. BFalse
66. 66Which of these strategies do prokaryotic cells use to isolate and organize their chemical reactions?

    1. Aconfining proteins required for different metabolic processes within different membrane-enclosed compartments
    2. BNone; prokaryotes do not regulate their metabolic processes.
    3. Caggregating proteins into multicomponent complexes that form biochemical subcompartments with distinct functions
    4. DNone; these strategies are used only by eukaryotic cells.
    5. Econfining the proteins required for different metabolic processes within the plasma membrane
67. 67How do the interiors of the ER, Golgi apparatus, endosomes, and lysosomes communicate with each other?

    1. AThey do not communicate with one another.
    2. Bby open pores that allow ions to exit and enter the organelles
    3. Cby fusing with one another
    4. Dby excreting hormones and other small signaling molecules
    5. Eby small vesicles that bud off of one organelle and fuse with another
68. 68Most mitochondrial and chloroplast proteins are made within which part of the cell?

    1. Aendoplasmic reticulum
    2. BGolgi apparatus
    3. Ccytosol
    4. Dperoxisome
    5. Emitochondrion or chloroplast itself
69. 69What happens to proteins with no signal sequence that are made in the cytosol?

    1. AThey are taken up by lysosomes.
    2. BThey remain in the cytosol.
    3. CThey are returned to their organelle of origin.
    4. DThey are secreted.
    5. EThey are degraded by proteases.
70. 70Which proteins bind to nuclear localization signals on newly synthesized proteins?

    1. ANuclear import receptors
    2. BNuclear pore proteins
    3. CSignal-recognition particles (SRPs)
    4. DCytosolic fibrils
    5. ENuclear export receptors
71. 71Proteins destined for the Golgi apparatus, endosomes, lysosomes, and even the cell surface must pass through which organelle?

    1. AMitochondrion
    2. BPeroxisome
    3. CNucleus
    4. DER
72. 72As a polypeptide is being translocated across the membrane of the endoplasmic reticulum, a stop-transfer sequence can halt the process. What eventually becomes of this stop-transfer sequence?

    1. AIt remains in the cytosol.
    2. BIt is translocated into the lumen of the endoplasmic reticulum.
    3. CIt stops protein synthesis and causes the ribosome to be released back to the cytosol.
    4. DIt forms an α-helical membrane-spanning segment of the protein.
    5. EIt is cleaved from the protein.
73. 73The movement of materials from the plasma membrane, through endosomes, and then to lysosomes describes which type of pathway?

    1. Aendolytic pathway
    2. Bendosomal pathway
    3. Csecretory pathway
    4. Dexocytic pathway
    5. Eendocytic pathway
74. 74Which proteins play a central role in the fusion of a vesicle with a target membrane?

    1. ASNAREs
    2. BAdaptin
    3. CRab proteins
    4. DTethering proteins
    5. EClathrin
75. 75Through which of the following do proteins travel from one cisterna to the next in the Golgi apparatus?

    1. Atransporters in the cisternal membranes
    2. Bbridges that link the cisternae
    3. Cmembranes via osmosis
    4. Dpores in the cisternal membranes
    5. Etransport vesicles that bud from one cisterna and fuse with the next
76. 76The drug vinblastine disrupts microtubule polymerization. How would adding vinblastine to a cell affect the constitutive secretory pathway?

    1. ATransport vesicles will only be brought to the Golgi apparatus, not to the plasma membrane.
    2. BVinblastine will not affect the pathway because microtubules are not involved in secretion.
    3. CTransport vesicles will only be brought to the plasma membrane, not to the Golgi apparatus.
    4. DTransport vesicles will not be brought to either the Golgi apparatus or the plasma membrane.
77. 77During a pulse-chase experiment with secreted proteins, the proteins are synthesized for a short “pulse” time with radioactive or fluorescent amino acids to label the proteins. During the “chase” period, unlabeled amino acids are added, so any additional proteins synthesized are not labeled. The labeled proteins can then be monitored over time. You complete a pulse-chase experiment to monitor the secretion of a protein from the cell. Which of the following correctly lists the order of locations of the protein during the chase period?

    1. AGolgi → transport vesicle → endoplasmic reticulum → transport vesicle → secreted
    2. Bnucleus → endoplasmic reticulum → cytosol → Golgi → transport vesicle → secreted
    3. Cendoplasmic reticulum → transport vesicle → Golgi → cytosol → secreted
    4. Dendoplasmic reticulum → transport vesicle → Golgi → transport vesicle → secreted
78. 78How are newly made lipids supplied to the plasma membrane?

    1. Avia vesicles that bud from the ER and fuse with the plasma membrane
    2. Bvia the constitutive pathway of exocytosis
    3. Cvia enzymes that synthesize phospholipids, which are attached to the plasma membrane
    4. Dvia lysosomes
    5. Evia secretory vesicles produced by the regulated exocytosis pathway
79. 79What is true of protein glycosylation in the ER?

    1. AA block of sugar residues is added to the N-terminal signal sequence, creating a common, N-linked oligosaccharide.
    2. BOnly proteins phosphorylated on an asparagine residue become glycosylated.
    3. COligosaccharides are added by an enzyme that has its active site on the lumenal side of the ER membrane.
    4. DSugar residues are added one at a time by a series of enzymes attached to the ER membrane.
    5. EOnly proteins bearing a dolichol residue become glycosylated.
80. 80Phagocytosis is a process by which cells do which of the following?

    1. Aingest extracellular fluid and macromolecules
    2. Bdigest their own worn-out organelles
    3. Cconsume large particles, such as microbes and cell debris
    4. Dsecrete hormones and neurotransmitters
    5. Eengage in receptor-mediated endocytosis
81. 81Which of the following is true of lysosomes?

    1. AMost of the lysosomal membrane proteins have glycosylated regions on the cytosolic side of the membrane.
    2. BThe products of digestion in lysosomes leave the lysosome by transport vesicles.
    3. CAn ATP-driven H+ pump in the lysosomal membrane maintains the organelle's pH.
    4. DLysosomes contain around 40 types of hydrolytic enzymes, which are optimally active at pH 7.2.
    5. ELysosomes have a pH that is higher than that of the cytosol.
82. 82Which cellular compartment acts as the main sorting station for extracellular cargo molecules taken up by endocytosis?

    1. ATransport vesicles
    2. BGolgi apparatus
    3. CLysosomes
    4. DClathrin-coated vesicles
    5. EEndosome
83. 83Match the following structures used in receptor-mediated endocytosis with their functions.

    

    1. ATrue
    2. BFalse
84. 84Organisms that live in cold climates adapt to low temperatures by doing which of the following?

    1. Adecreasing the amounts of unsaturated fatty acids in their membranes to help keep their membranes fluid
    2. Bincreasing the amounts of saturated fatty acids in their membranes to help decrease the fluidity of their membranes
    3. Cincreasing the amounts of unsaturated fatty acids in their membranes to help keep their membranes fluid
    4. Dincreasing the amounts of unsaturated fatty acids in their membranes to help decrease the fluidity of their membranes
    5. Eincreasing the amounts of saturated fatty acids in their membranes to help keep their membranes fluid
85. 85When the transport vesicle shown below fuses with the plasma membrane, which monolayer will face the cell cytosol?

    

    1. AThe orange monolayer will face the cytosol
    2. BThe blue monolayer will face the cytosol
    3. CIt depends on whether the vesicle is coming from the endoplasmic reticulum or the Golgi apparatus
    4. DHalf the time the orange monolayer will face the cytosol, and half the time the blue monolayer will face the cytosol
    5. EIt depends on the cargo the vesicle is carrying
86. 86Animals exploit the phospholipid asymmetry of their plasma membrane to distinguish between live cells and dead ones. When animal cells undergo a form of programmed cell death called apoptosis, phosphatidylserine—a phospholipid that is normally confined to the cytosolic monolayer of the plasma membrane—rapidly translocates to the extracellular, outer monolayer. The presence of phosphatidylserine on the cell surface serves as a signal that helps direct the rapid removal of the dead cell.
    
    How might a cell actively engineer this phospholipid redistribution?

    1. Aby activating a scramblase and inactivating a flippase in the plasma membrane
    2. Bby inverting the existing plasma membrane
    3. Cby inactivating a scramblase in the plasma membrane
    4. Dby inactivating both a flippase and a scramblase in the plasma membrane
    5. Eby boosting the activity of a flippase in the plasma membrane
87. 87All of the carbohydrates in the plasma membrane face the cell exterior. Which direction do the carbohydrates on internal cell membranes face?

    1. AThe cell exterior
    2. BThe cytosol
    3. CThe lumen of the vesicle or organelle
    4. DThe glycocalyx
    5. EThe plasma membrane
88. 88Shown is a schematic diagram of a membrane phospholipid. Which segment could carry a positive charge?

    

    1. AA
    2. BB
    3. CC
    4. DD
    5. EE
89. 89In general, which of the following will diffuse across a lipid bilayer most rapidly?

    1. Aa large hydrophobic molecule
    2. Ba small hydrophilic molecule
    3. Ca large hydrophilic molecule
    4. Da small hydrophobic molecule
    5. Ewater
90. 90Which type of membrane transport protein can perform either passive or active transport?

    1. ANeither type of membrane transport protein can perform both passive and active transport.
    2. BChannels
    3. CBoth channels and transporters
    4. DTransporters
91. 91Which of the following correctly describes osmosis?

    1. Athe movement of water from an area of low solvent concentration to an area of high solvent concentration
    2. Bthe movement of water from an area of low solute concentration to an area of high solute concentration
    3. Cthe movement of water from an area of high solute concentration to an area of low solute concentration
    4. Dthe movement of water from an area of low water concentration to an area of high water concentration
92. 92Why do cells lack membrane transport proteins that are specific for the movement of O2?

    1. Abecause oxygen dissolves readily in lipid bilayers
    2. Bbecause oxygen is transported in and out of the cell by special oxygen-binding proteins such as hemoglobin
    3. Cbecause oxygen concentrations must be kept low inside cells to avoid creating reactive superoxide radicals that can damage DNA and proteins
    4. Dbecause oxygen, dissolved in water, can enter cells via aquaporins
    5. Ebecause transport of oxygen across cell membranes is energetically unfavorable
93. 93What are the end products of glycolysis?

    1. AATP
    2. BH2O + CO2
    3. CNADPH
    4. DNADH
    5. EAcetyl CoA
    6. FADP
    7. GPyruvate
94. 94In cells that cannot carry out fermentation, which products derived from glycolysis will accumulate under anaerobic conditions?

    1. Apyruvate and NADH
    2. Bpyruvate and NAD+
    3. Clactate and NAD+
    4. Dglucose and NADH
    5. Eglucose 6-phosphate and NADH
95. 95Determine whether the following statement is true or false: The oxygen consumed during the oxidation of glucose in animal cells is returned to the atmosphere as CO2.

    1. ATrue
    2. BFalse
96. 96Which is true about electrons as they move through the electron-transport chain?

    1. AElectrons start out at very high energy and lose energy at each transfer step along the electron-transport chain.
    2. BElectrons neither gain nor lose energy as they move along the electron-transport chain.
    3. CElectrons start out at very low energy and gain energy at each transfer step.
    4. DElectrons can gain or lose energy, depending on where they enter along the electron-transport chain.
    5. EElectrons are pumped across the mitochondrial membrane as they move along the electron-transport chain.
97. 97The electron-transport chain pumps protons in which direction?

    1. Afrom the matrix to the intermembrane space
    2. Bfrom the intermembrane space to the matrix
    3. Cfrom the matrix to the cytosol
    4. Dfrom the cytosol to the intermembrane space
    5. Efrom the intermembrane space to the cytosol
98. 98During oxidative phosphorylation, why does a single molecule of NADH result in the production of more ATP molecules than a single molecule of FADH2?

    1. AFADH2 is less likely than NADH to participate in the electron-transport chain.
    2. BFADH2 has a lower electron affinity than does NADH.
    3. CNADH donates more electrons to the electron-transport chain than does FADH2.
    4. DFADH2 and NADH feed their electrons to different carriers in the electron-transport chain.
    5. EFADH2 promotes the pumping of more protons than does NADH.
99. 99In muscle cells, which organelle sequesters Ca2+ from the cytosol?

    1. ARough ER
    2. BLysosome
    3. CMitochondrion
    4. DSmooth ER
    5. EEndosome
100. 100Which molecule is displaced when a vesicle and its target membrane fuse?

     1. ASNAREs
     2. BTethering proteins
     3. CPhospholipids
     4. DWater
     5. EClathrin
101. 101A single-pass transmembrane protein destined for one of the organelles in the endomembrane system would be marked by what type of signal sequence?

     1. Aan internal ER signal sequence
     2. Ban internal ER signal sequence and an internal stop-transfer sequence
     3. Ca cleaved N-terminal ER signal sequence and an internal stop-transfer sequence
     4. Da cleaved N-terminal ER signal sequence

Description

Quiz on Cell Bio Exam Three, created by Kealy L on 17/10/2019.

Author

Kealy L

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