Practice Questions

d. Ezrin needs to link actin to the membrane 16. Which of the following is true about nuclear lamina? a. Nuclear lamina has no links to the cytoplasmic cytoskeleton b. Nuclear lamina is a three-dimensional network of microfilaments c. Nuclear lamina supports the inner nuclear membrane d. Nuclear lamina covers the cell nucleus 17. The apical area of many epithelial cells contain circumferential belts that can facilitate a change in shape in these cells such that the shape of an entire sheet of cells is altered. Such a shape change facilitate by circumferential belts is due to a. Integrin links to the ECM b. Cadherin links to actin c. Cadherin links to keratin d. Integrin links to actin 18. The cytoskeleton can generate a variety of movements in cells, two of which are cytokinesis are the propulsive forces generated by flagella. Which components of the cytoskeleton are linked with these movements, respectively? a. Microtubles and intermediate filaments, respectively b. Intermediate filamenets and microtubules, respectively c. Microfilaments and microtubules, respectively d. Microfilaments and intermediate filaments, respectively 19. The cell cortex is an actin-based structure that underlies the membrane of most cells. How many of these proteins contribute to this cortical actin network a. Ankyrin b. Arp2/3 c. Spectrin d. Filamin 20. In a scratch wound closure assay, cells are treated with inhibitors Rho kinase. Would would be observed a. Rho inhibited cells would close the wound faster as there are more stress fibers b. An increase in cdc42 in Rac would result in cells of unusual shapes that would quickly close the wound c. Rho inhibition would reduce wound closure d. Rho inhibition would interefore with Arp2/3 thus only actin bundle protrusions would close the wound 21. Tubulin has many isoforms and the amount of each many vary between cell-types. You are aware that there are at least three tubulin isoforms and would like to purify one to make a monoclonal antibody (mAb) that specifically recognizes only the y-isoform. Where would be the best place to collect y tubulin to use for mAb production. a. Astral microtubules b. Centromere c. Axoneme d. Pericentriolar matrix

f. Binding of glucocorticoid to the LBD of the glucocorticoid receptor 5. In the intrinsic apoptic pathway, a mitochondrion’s outer membrane is permeabilized by which protein a. Bim b. Bad c. Bax d. Bcl-12 6. A cell line was transfected with plasmids in order to express both Bcl-2 fused to CFP, and Bax fused to YFP. This cell line also expresses the TNFa receptor. What would you expect to see if you treated the transfected cells with TNFa? a. No change in the FRET signal before or after the TNFa exposure b. Decrease in the FRET signal at the plasma membrane c. An increase in the FRET signal in the mitochondrial outer membrane d. A decrease in the FRET signal in the mitochondrial outer membrane 7. What are the arrows pointing to in the picture below? a. Apoptic cells in a C. elegans worm visualized by DIC microscopy b. Undead cells in a TEM image of webbed toes c. Lysosomes in a live C. elegans worm visualized by phase contrast microscopy d. Autophagic vesicles captured by SEM in an immature C. elegans worm 8. Why would taking viagra and a drug that acts as an agonist (activator) of muscarinic acetylcholine receptors possibly be bad? a. Viagra will cause increased blood flow to the penis will the agonist will cause less blood flow to the heart which would promote a heart attack b. Viagra will promote increased PKG activity and relaxation of vascular smooth muscles while the agonist will open Ca2+ channels and deplete cardigan myocytes of the necessary ion for muscle contraction, possibly leading to a heart attack

c. Because they promote the destruction of transcription factors in a controlled manner at each stage of the cell cycle d. Because they promote the destruction of cdks in a controlled manner at each stage of the cell cycle 22. After transfecting a cDNA library into a cell line you find that some of the transfected cells now respond to a growth factor that they previously didn’t respond to. PCR amplification using plasmic-specific primers results in the amplification of a unique cDNA in the responding cells. How would you confirm that this cDNA encodes for the growth factor receptor? a. Make a monoclonal antibody that recognizes the receptor then use FACS to isolate the cDNA expressing cells b. Express a GFP-tagged version of the putative receptor in cells, then add a YFP-tagged growth factor and try to detect a FRET signal c. Mutate certain sequences in putative ligand binding domains and see if cells expressing the mutant protein no longer respond to the growth factor d. None of the above 23. What would be the effect of deleting the COP1 gene in a cell line? a. Cells that direct secreted proteins to the lysosome b. One of the cells from a four stage embryo c. Cells with increased secretion of ER resident proteins d. Cells incapable of secreting proteins 24. What sequence of events are required for PKC activation? a. Binding of a ligand to a GPCR, activation of adenyl cyclase, activation of NO synthase, increased cGMP production, release of Ca2+ from the ER b. Binding of a ligand to a GPCR, activation of Gas, activation of phospholipase C, production of IP3 and DAG, release of Ca2+ from the ER c. Binding of a growth factor to a RTK, autophosphorylation of the RTK, activation of Ras, activation of Raf, phosphorylation of PKC d. Binding of a ligand to a GPCR, associated with the trimeric G-protein complex, dissociation of GDP, binding and hydrolysis of GTP, activation of adenyl cyclase, activation of calmodulin 25. You engineer a cell to express both the HER2 receptor and EGF. these cells can now grow in culture without the addition of serum. What type of signalling does this engineered cell exemplify? a. Autocrine signalling b. Endocrine signalling c. GPCR signalling d. Retrograde signalling 26. What would happen if you overexpressed a MAPK that constitutively phosphorylates and activates Wee1 in yeast cells a. The cells would prematurely enter mitosis b. The cells would arrest in G2 phase c. The cells would become very small d. The cells would arrest in G1 phase

b. The cell free extract contained a virus which produced a version of the HER2 receptor lacking the extracellular ligand binding protein c. The cell free extracts contained a virus which produced a constituvely active version of GRB2 d. The cell free extracts contained a virus containing a gene which encoded a constantly active version of Ras 34. Amplification of HER2 gene is detected in ~25% breast cancer patients. What is NOT TRUE about the signaling mechanism responsible for aggressiveness of HER2 positive breast cancers? a. HER2 can form heterodimers with other receptor tyrosine kinases b. HER2 functions as a receptor tyrosine kinase c. HER-2 positive cancer cells trigger apoptosis of adjacent immune cells d. HER2 is involved in the signal transduction leading to cell growth 35. How many of the following molecules are required to open the K+ channel in heart muscle cells (4) a. Acetylcholine b. Gbd subunit c. Adenylil cyclase d. ATP e. GTP f. cAMP g. Muscarinic acetylcholine receptor h. Epinephrine 36. COPII is always a. Cytosolic b. Lumenal c. Lysosomal d. Exoplasmic 37. A hypothetical cell exists in which there are high levels of glucose on the exoplasmic side of a lysosomal membrane. There is also a functioning GLUT1 uniporter present in this lysosomal membrane. As a result a. Glucose will leave the lysosome through active transport b. Glucose will enter the lysosomal through active transport c. Glucose will enter the lysosomal through facilitated transport d. Glucose will leave the lysosomal through faciliated transport e. Glucose and Na+ will enter the lysosome via secondary active transport f. Glucose and Na+ will leave the lysosome via secondary active transport 38. Why is a P-class pump required during muscle contraction? a. To faciliate contraction b. To prevent tropomodulin from binding to actin c. To terminate the contraction d. It allows entry of glucose into the sarcomere e. It faciliates entry of ATP into the cell 39. What is not a feature/structure associated with this cell?

b. Basal microvili c. Basal ECM d. Lateral desmosomes e. Lateral tight junctions 45. In this diagram of a functioning sarcomere, how many of the following can be at the location indicated by the arrow? (2) a. Capz b. Minus end of actin c. Z-disk d. I-band e. Tropomodulin f. Pahlloidin g. Titin 46. Which of the following molecules are common to both desmosomes and hemidesmosomes a. Integrins b. Microtubules c. Microfilaments d. Intermediate filaments e. Two of the above 47. Which of the following is not true regarding a symporter? a. One molecule moves with the gradient one against the gradient b. It’s ATPase activity is contained in its cytoplasmic domain c. It is secondary active transport d. It is a transmembrane protein 48. How many of the following require ATP hydrolysis in their function a. Kinesin-13 b. Kinesin-5 c. Active transport d. Muscle contraction e. Mitosis 49. A drosophila gene called Ten-a is a type II transmembrane protein. While its precise function is not known, it binds to a protein called tenascin. Tenascin is an ECM molecule. From this we can deduce taht a. The C-terminal domain of Ten-a and the tenascin molecule could both be in the ER at the same time b. Ten-a and tenascin both have anchor sequences c. Ten-a and tenascin both have STA sequences d. The N-terminal domain of Ten-a is uncharged e. Neither Ten-a nor tenascin needs a translocon during their translation 50. Membrane melting point ____ with ____ chain length, as melting point _____ with _____ unsaturation a. Increases increasing increases increasing b. Decreases increasing increases increasing

63. How many of the following directly involve the cytoskeleton? (3) a. Karyokinesis b. potassium resting channel c. ABC pump d. Hemidesmosome e. Microvilli 64. V-snare is a tail anchored protein. Accordingly, a. ATP is required to cleave its C-terminal tail b. Its N-terminal signal is recognized by Get3 c. It has a hydrophobic C-terminus d. Its exoplasmic domain is crucial to its function of facilitating membrane fusion 65. What is not a property of an integral membrane protein? a. A signal sequence b. Glycosylated beta barrel c. A hydrophobic domain d. A hydrophilic domain e. A transmembrane domain 66. Decoration of cytoskeletal components with myosin S1 is commonly used to: a. Attach actin filaments to cell membranes b. Disassemble microfilaments c. Reveal the polarity of microtubules d. Drive (+) end directed motion e. None of the above 67. In the nomenclature of fatty acids of Cx:y a. Y=number of polysaturations b. X=number of H+ c. X= number of carbons d. Y=number of oxygens 68. Lamin B is prenylated to the nuclear membrane, from that we know a. It has an N-terminal glycine b. Lamin B is cytosolic c. Its n terminal is free within the cell membrane d. It is attached via a GPI 69. Gut epithelial cells essential role in nutrient uptake depends on their polarity. Which is not required for glucose uptake at the apical surface? a. Symporter transport b. Tight junctions c. Potassium resting chanel d. Canal junctions 70. Which statement is incorrect? a. The mitotic apparatus is made up of asters and a spindle b. Microtubule binding to the kinetochore occurs before metaphase c. Spindle organization and function depends on motor proteins d. Asters are not associated with motor proteins

i. Would not happen. Dimers always stay together, this is the best answer as it was mentioned in class several times 10. In this image of a cell that has its MT network labeled fluorescent green, the cytoplasmic MT radiates out from a central MTOC. What is not present in the black cellular space between the green structures? a. Augmin b. Cytoplasm c. Golgi d. Lysosomes 11. How many protofilaments does a typical centriole MT have? a. 3 b. 2 c. 23 d. 33 12. What occurs during the process indicated by the unlabelled red arrow?

a. Reenergizing of the beta subunit b. The alpha subunit utilizes ATP c. Gamma-tubulin nucleating d. Protofilament nucleation leading to cap formation 13. Which domain is always present in different types of kinesins? a. GTPase domain b. Light chain c. Tail domain d. Head domain 14. The assembly of functionally active conventional kinesin-2 for anterograde transport needs a. Two heavy chains and two heterocomplexees b. Two identical heavy chains and two light chains c. One heavy chain and one light chain d. Two different heavy chains and one light chain 15. What is the functional significance of alpha tubulin subunit acetylation at a lysine residue? a. It blocks the activity of motor proteins b. It activates the anterograde polymerization of microtubules c. It facilitates binding of MAPs to microtubules d. It stabilizes the microtubules and promotes kinesin-1 movement

16. Kinesin 1 is not bound to a microtubule a. When there is excess dynein b. When it is supporting the membrane in cilia c. When its variable light chains have not yet bound to cargo d. When it is playing an active role in microtubule depolymerization 17. The (+) end of microtubules, which are attached to the kinetochore complex, a. Covalently binds to kinetochore proteins b. Are phosphorylated by Ndc80 c. Are completely protected from polymerization d. Can grow or shrink 18. What is the key molecular mechanism of Anaphase A in terms of chromosome movements? a. Microtubule sliding facilitate by motor proteins b. Microtubule polymerization at the (+) end c. Microtubule depolymerization at both ends d. Pulling of microtubules by the centrosome 19. You analyze the cross-section of a cilium-like structure and notice that the axonemal dynein is missing while nine microtubule doublets are present. What does it tell you? a. The structure is most likely a basal body b. This structure is most likely a flagellum c. This structure is most likely a primary cilium d. This structure is most likely half of a centriole 20. A mutation occurs in Ndc80 such that once phosphorylated, it can not be dephosphorylated a. This would affect signalling in the primary cilium b. Axonemes would not bend as doublet microtubules would slide freely c. Thus, anaphase cannot begin as chromosomes could not separate d. As a result, bound microtubules would be released by the kinetochore 21. Which of the following correctly matches a mitotic motor protein with its function? a. Kinesin-2 interacts with polar microtubules to pull the chromosomes toward the center of the spindle b. Kinesin-13 enhances microtubule (+) end growth, promoting kinetochore attachment c. Kinesin-5 facilitates microtubule sliding d. Membrane-bound dyneins facilitate bi-direction pushing that aids in kinetochore-microtubule shortening 22. What is happening with the microtubule cytoskeleton when cells enter mitosis? a. Singlet microtubules transform into doublets and triplets b. MAP levels increase while kinesin levels decrease c. Microtubules become more stable d. Microtubules become less stable 23. What is happening with the transition zone of cilia or flagella during axonemal transformation? a. Polymerization of microtubules switches from triplets to doublets

b. Polymerization of microtubules switches from singlets to doublets c. Polymerization of microtubules switches from doublets to singlets d. Polymerization of microtubules switches from doublets to triplets 24. Sperm cells travel very fast using flagellar movements. What induces wave-like movements of flagella? a. Dynein-mediated local sliding of microtubule doublets in the axoneme b. Dynamic local instability of axonemal microtubules that is restricted by nexin c. Kinesin-mediated local sliding of parallel microtubule in the axoneme d. Sequential proteolytic degradation of nexin proteins connecting microtubule doublets 2018 1. During polymerization of actin or tubulin a “nucleus” is fundamental to early events. Such a nucleus plays an important role a. To ensure growth at times when we lower our body temperatures to 4 degrees celsius, as that can negatively impact polymerization b. In guaranteeing that the + end polymerizes faster than the - end c. In linking structural actin and microtubule filaments such that vesicles can be transported between them d. None of the above 2. In the diagram below, what is represented by the *? a. Empty space b. Mitotic pole c. Cytoplasm d. Focal junction 3. How many of the following are true regarding microtubule triplets a. Found in centrosomes b. Found in basal bodies c. Contains 23 microfilaments d. Composed of a and B and y tubules e. Found in the Z-disk f. Are bound to membrane by ezrin

4. A gamma tubulin antibody is added to a dendrite, and when detected immunologically the antibody reveals multiple spots along the length of the dendrite. This demonstrates that a. Both ends of each microtubule are capped b. The microtubules are not continuous down the length of the dendrite c. Augmin is present in the dendrite d. Gamma tubulin is being transported by dynein 5. Fraying of microtubule ends during depolymerization occurs due to a. Loss of lateral binding abilities between GDP-beta tubulin in adjacent protofilaments b. Loss of binding between GDP-beta tubulin within the dimer c. Gain in ability of the dimer to attract MAPs d. 2 of the above are true 6. An in vitro experiment is set up such that all components (including templates that can act as nucleators) needed for actin polymerization are present. Monomers are added such that the amont of available ATP-actin is kept at 0.72 µM. After polymerization begins CapZ, taxol, and Rho-GTP are then also added. What is likely to happen? a. Treadmilling b. There will be no polymerized microfilament present c. Growth only at the + end d. Growth only at the - end 7. A kinesin-1 motor protein that is migrating along a microtubule is treated in such a way that both its head domains stick as they contact the microtubule. The heads are thus frozen mid-stride and both remain in contact with the microtubule a. The 2 heads are thus 8 µM apart b. The 2 heads are thus 16 µM apart c. The 2 heads are bound to the same dimer d. The motor protein would release its cargo 8. A cell undergoing mitosis is being observed. While the cell elongates, the chromosomes fail to move closer to the mitotic poles. Why might this have occurred? a. Motor proteins have been inhibited b. Microtubules have been capped by gamma-tubulin c. There is excess kinesin-12 d. Kinetochore proteins have released kinetochore microtubules 9. Dynein and kinesin motor protein complexes are isolated and each complex is separated on SDS-page gels and stained to visual proteins. Analysis suggests that more proteins are found in the dynein motor complex than kinesins. This is due to the fact that a. There are more dynein than kinesin family members b. Recognition of cargo for retrograde transport involves a complex of proteins c. Dynein also transports kinesin d. Anterograde transport only moves simple cargo 10. In the above diagram, how many of the following can be at the location indicated by the arrow?

a. Capz b. + end of actin c. Z-disk d. A-band e. Trpomodilin (- end) f. Colchicine g. Vimentin 11. What is needed for branching to occur during actin polymerization? a. Formin needs to be activated by arp2/3 b. An NPF such as WASp needs to be activated c. Ezrin need to link actin to the membrane d. A pathogen needs to activate WAVE 12. Which protein is expressed in a cell-specific manner and binds to the tripeptide sequence Arg-Gly-Asp? a. Integrin b. Collagen c. Proteoglycan d. Fibronectin 13. Which is not required for anaphase A to occur? a. De-phosphorylation of ndc80 b. Depolymerization of the + end of the kinetochore-microtubule c. - end movement of the chromosome by dynein d. + end contact of the kinetochore-microtubule to the kinetochore protein 14. During axonemal bending a. Nerve axon flexing is limited by MAPs to prevent damage b. Microtubules slide as bi-polar myosin moves to the + end c. Microtubule sliding is limited d. Localized proteases function to bend microtubule doublets 15. During the polymerization of actin as seen in the above graph, what does the arrow represent? a. The mass of the growing protofilament b. The mass of free-monomers c. The mass of polymerized actin d. The mass of free dimers 16. xMAP215 activity is related to a. Spindle stability

b. Axonemal stability c. Centriole stability d. Doublet stability 17. Actin microfilament treadmilling a. Occurs any time when CapZ and tropomodulin are absent b. Requires actin monomers in the ATP form c. Is accelerated by kinesin-13 activity at the + end d. Drivers cytokinesis 18. Which is NOT associated with arp2/3 function? a. Vesicle transport b. Lamelliopodia formation c. ECM recognition d. Pathogen phagocytosis 19. You are examining a cell with a microscope and you note 10nm thick filaments extending from a structure that links the membranes of two cells. You are looking at a. Ankyrin b. A desmosome c. Formin-capped actin d. Cytoplasmic streaming through gap junctions 20. Epithelial cells have many functions, including nutrient uptake. To maximize nutrient uptake some cells utilize microvili. And to maximize strength and barrier function, several modes of adhesion are used, including a. Hemidesmosomes to ensure tight focal adhesion binding to the apical ECM b. JAM proteins near the apical surface to prevent passage of materials between cells c. GAP junctions to enable cytoskeletal fibers to pass between cells d. Integrins activated by selectins to glue apical surfaces to prevent passage of materials between cells 21. During mitosis many changes occur as a cell separates its replicated DNA. which does NOT occur? a. Intermediate filament associated LINC support is reduced? b. A serine in the N-terminal domain of lamin A is phosphorylated c. The centrioles replicate d. Kinesin V aids karyokinesis via microtubule-dependent movement of the nucleus towards the division plate 22. During cell migration, what is happening at the leading edge of the cell a. Cdc42 led stress fiber formation is followed by membrane extension b. Cdc42 polarity guides microtubule anterograde transport c. Dominant active cdc42 results in excess actin branching d. Dominant active cdc42 results in integrin activation 23. How many of the following are characteristics of fibronectin? a. It is an ECM protein b. It contains an RGD motif c. It is recognized by a5B1 integrin

d. It facilitates cell migration 24. During extravasation a. A red blood cell leaves the artery to fight infection b. PAF binds to the PAF receptor c. ICAM sugar residues are recognized by integrins d. Bacterial toxins directly activate integrins 25. Which of the following is NOT a function of myosin-powered movements? a. Skeletal muscle contraction b. Cytoplasmic streaming c. Cytokinesis d. Flagellum-mediated cell motility 26. If the binding activity of thymosin was inhibited in a migrating cell, the overall effect would be: a. A decrease in cell locomotion because less actin would be recruited to the leading edge b. An increase in cell locomotion because there would be a higher concentration of actin available c. No change in cell locomotion because thymosin doesn’t interact with Rho, Rac, or Cdc42 d. No change in cell locomotion because the actin is still trapped within the ER 27. Which of the following does NOT belong to the intermediate filament protein family? a. Vimentin b. Keratin c. Laminin d. Desmin 28. The functions of the extracellular matrix include: a. Engulfing and anchoring the nucleus b. Facilitating cell migration c. Regulating the metaphase plate d. 2 of the above are correct answers 29. The major families of cell surface adhesion molecules does NOT include: a. Cadherins and selectins b. Integrins c. The Ig-superfamily d. Fibronectin 30. A mutation occurs in a striated muscle such that the myosin head does not bind to the actin. Which of the following could NOT cause such an event? a. Calcium channel release problems b. Failure of the myosin to release Pi after ATP hydrolysis c. Removal of the transverse-tubules d. A troponin mutation 31. Which statements best describe the structure of integrins? a. Integrins cluster in groups of 6 on either side of the junction b. Integrins are homodimers of subunits expressed in a cell-type specific manner

c. A single integrin subunit forms heterophilic interactions with the ECM d. Integrins are heterodimers composed of a and B subunits 32. The head domain of kinesin-5 is mutated such that it can associate with microtubules but cannot hydrolyze ATP. what stage of mitosis would be affected by this mutation? a. Metaphase b. Anaphase A c. Anaphase B d. Both b and c 33. In which of these structures would you NOT expect to find fimbrin? a. Microvili b. Cilia c. Filopedia d. All of the above 34. What do Tau, EB1, and plectin share? a. They are responsible for the retrograde transport of vesicles in nerves b. They utilize taxol to stabilize the cytoskeleton c. The ability to bind to microtubules d. They form protein aggregates that disrupt nerve function 35. What do focal adhesions and hemidesmosomes share? a. Both involve ECM binding b. Both involve homophilic cell adhesion molecules c. Both involve intermediate filament binding d. Both involved NCAM binding 2017 1. A mutation occurs in ndc80 such that it can not be dephosphorylated a. Thus, the chromosomes could not condense b. This would not affect mitosis c. This would eliminate all polar microtubules as they are released by the kintochore d. This could result in aneuploidy 2. In the investigation of microtubule dynamics, a reagent called a “flagella nucleus” is often used. Its use is rational because a. Flagellar nuclei encode all genes needed for axonemal function b. These nuclei express dimer subunits that facilitate polymerization c. Doublet microtubules are stable d. Axonemes contain gamma tubulin 3. Why are some components of the microtubule cytoskeleton stable, while others are not a. Centrioles are stable as they never need to replicate b. Axonemal microtubules are not stable as they require depolymerization to facilitate bending c. Basal bodies are not coated with MAPs and therefore stable d. Acetylation of tubulin augments intraflagellar transport, but also promotes stability

4. An invitro experiment is being carried out, and one can observe a myosin S1 coated element where there is polymerization only at the end pointed by the arrowheads. Fom this one can deduce a. The concentration of actin monomers in the ATP form is below 0.4 µM b. capZ is present c. Myosin is moving to the plus end d. Cofilin is present 5. What is happening as indicated by the question mark (?) on the above graph? a. As material is added, the mass of protein accumulates b. All added dimers above Cc are added to the growing microtubule c. The Cc changes with mass d. The mass of the system has reached a steady-state 6. An important regulator of actin function is Arp2/3 a. Its regulation of actin dynamics plays important role in endocytosis and phagocytosis b. By binding the gamma-actin subunits at the minus end it facilitates plus end growth c. Arp2/3 needs to be first phosphorylated by RacGTP or Cdc2GTP d. Its key role is its ability to energize G-actin monomers from an ADP to an ATP form 7. Which is not associated with the above diagram a. Stathmin

b. Kinesin 13 c. Beta tubulin in the GDP form d. A Cc of less than 0.12 µM 8. Which of the following is true regarding Cdc42, Rac, or Rho? a. All are small ATPases b. Cdc42 coordinates actin and tubulin dynamics c. Rac and Rho are MAPs d. Cdc42 regulates nuclear membrane dynamics 9. During mitosis, XMAP215 a. Is depolymerized by kinesin-13 b. Is degraded by CDK c. Activity decreases d. More than one of the above answers is true 10. Cytoskeletal elements support membranes. As cells often need to change their shape - particularly during processes such as cytokinesis - such membrane interactions need to be mofidable. For example a. Our red blood cells need to alter their ankryin links during mitosis b. In response to CDK, lamin A aids in nuclear envelop breakdown c. The phosphorylation of beta-tubulin destabilizes all microtubule supported membranes d. Dystrophin bound LINC complexes release muscle membranes during mitosis 11. Which is NOT true regarding intermediate filament polymerization and function? a. Tetramer subunits are polar b. No ATP or GTP are needed c. No known motor proteins d. Great tensile strength 12. What would the consequence be of degrading and removing nexin from within the axoneme? a. There would be no intraflagellar transport b. Axonemal dynein would also be released c. The microtubules could still slide d. The microtubles would depolymerize 13. How many of the following are true regarding desmosomes? a. Are cell-cell adhesion junctions b. Utilize intermediate filaments c. Support the sarcomere d. Are present in migrating cells e. Bind to the ECM 14. During the chemotactic response of a specific cell, cAMP is used to attract the cell in a given direction. This chemotaxis would require: a. The cAMP receptor to be present throughout the membrane of the cell b. The activation of Cdc42 to occur on all cell surfaces of the cell c. The transcription of cAMP genes to direct the formation of focal adhesion d. The transcription of cAMP genes to direct the polymerization of Arp2/3

15. How many of the following are shared by intermediate filaments and tubulin? a. Can branch b. Are stabilized by caps c. Found in hemidesmosomes d. Have polarized filaments 16. Kinesin-1 is the prototypical anterograde transport motor and uses the hydrolysis of ATP to move the microtubule plus end a. This ATP hydrolysis is linked to polymerization b. The step size of this movement is dependent on tail length c. A kinesin head moves 16 nm per ATP hydrolysis d. The step size of this movement is dependent on the number of light chains bound 17. Cytoplasmic streaming a. Is beneficial in cells with a large volume b. Is driven by sarcomere contraction of actin and myosin c. Results after listeria infection d. Results due to actin polymerizaiton 18. With regards to the spindle, which of the following is NOT true? a. It is cytoskeletal b. It is composed of polar, kinetochore, and astral microtubules c. It provides the forces needed for chromosome movement d. It is not present during interphase 19. In the sarcomere figure above, identify the three items (A, B, and C respectively) a. Tropomodulin, titin, thick filament b. CapZ, desmin, thick filament c. Tropomodulin, nebulin, myosin light chain d. CapZ, titin, myosin light chain

20. Cytokinesis, one of the final processes of mitosis, must be complete with extreme fidelity so as to not interfere with the segregation of chromosomes. To ensure this a. The contraction of the actin ring is solely regulated by one molecule, cofilin b. The contractile ring is precisely placed accordingly to the location of the metaphase plate c. The astral microtubules prevent the ring from closing prematurely d. The contractile ring’s stability is tightly regulated by Arp2/3 21. A cell that contains vimentin would also be expected to contain a. Keratin b. Focal adhesions c. Desmin d. Axonemes 22. Which of the following is NOT a property of a basal body? a. It is considered a centrosome b. Is stable c. Is composed of protofilaments d. Is polar 23. Which mechanism in our body regulates function associated with all components of the cytoskeleton - tubulin, actin, and intermediate filaments? a. Temperature b. Kinase activity c. Acetylation d. ATPase activity 24. How can one distinguish if the transport is associated with actin or tubulin? a. Adding capping proteins will prevent actin-transport but not tubulin transport b. Adding taxol will prevent tubulin transport but not acin transport c. Adding cytochalasin will prevent actin transport but not tubulin transport d. Adding an ATPase inhibitor will prevent actin transport but not tubulin transport 25. What is the trigger of skeletal muscle contraction a. Nerve degeneration b. ATP binding c. Cytoplasmic calcium d. Actin stabilizaiton 26. Because actin is cortical a. It can rapidly respond to extracellular signals b. It can easily interact with MTOCs c. It is well-positioned to interact with the sarcoplasmic reticulum d. It plays important roles in flagellar movement 27. brefeldin-A is a drug used in cell studies that inhibits transport from the ER to the golgi. Accordingly, we know that this drug is actin upon a. Microfilament depolymerization b. Retrograde transport c. Myosin I function d. None of the above

28. During cell migration actin and myosin work together to alter cell shape as part of this process. A mutation occurs where thymosin within this cell is no longer function. As a result a. Actin would polymerize everywhere b. Stress fibers would form everywhere c. Focal adhesions would form everywhere d. Microvilin would form everywhere 29. Human red blood cells are specialized, and while relatively short-lived, are quite resilient. This strength and resilience is a result a. Transmembrane proteins and band 4.1 proteins b. Spectrin’s ability to bundle parallel actin c. Filamin’s ability to cross-link actin d. Actin’s high tensile strength 30. Kinesin-1 is not bound to a microtubule a. When it is playing an active role in microtubule depolymerization b. When its variable light chains have not yet bound to cargo c. When there is excess dynein d. When it is supporting the membrane in cilia 31. What is the state of the myosin heads in a skeletal muscle cell as calcium is about to be released from the sarcoplasmic reticulim a. The myosin is bound to actin b. The myosin is bound to ATP c. The myosin is bound to ADP+Pi d. The myosin is bound to ADP 32. Dynein release of cargo can be triggered by a. P150glued b. Dynamitin c. Competition with kinesin02 d. Taxol 33. Dozens of different cell types in your body carry out extremely complex processes. Liver cells produce a variety of metabolic enzymes. Neuronal cells in your brain are responsible for movement and memories. Skin afford protection and sensation. All cells are many components - including cytoskeletal elements. However a. Spem cells do not contain any cytoskeletal elements as their size has been greatly reduced b. Red blood cells have no cytoskeletal as they have no nucleus c. Muscle cells have specialized intermediate filaments to handle tension stressed d. Nerve cells have extensive microtubule structures, but no motor proteins as the cytoskeleton is stable 34. At which stage during mitosis is a kinesin-5 function critical? a. DNA replication b. Anaphase B c. Cytokinesis

d. Anaphase A 35. During metaphsae, all chromosomes are aligned. This is achieved by a. Motor proteins associated with the outer kinetochore ring b. Dynein at the mitotic apparatus poles pulling on the chromosomes c. Kinesin-13 activity shortening all spindle microtubules d. Polar microtubules overlapping equally, thus centering the chromosomes 2015 1. How many of the following would prevent the growth of, and/or addition of G-actin in the ATP form to, the minus end of a microfilament? a. A G-actin concentration of 0.07 µM b. CAPZ c. Profilin d. Cytochalasin e. Titin f. SI myosin g. Excess formin h. Excess LAP2 2. Myosin II and kinesin 5 are similar in that they a. Are both minus end directed motors b. Both are polar c. Both are ATPases d. Are both involved in axonal transport 3. Muscular dystrophy arises in part due to the damage sustained by muscle cells that contract while their cytoskeleton is not properly tethered to the extracellular matrix. Such a tether requires a. Dynamic vimentin polymerization b. A transmembrane receptor c. Dystrophin secretion d. A change in membrane polarity 4. A leucocyte responding to an immunological cue is in the process of phagocytosis an invading foreign body. During phagocytosis the cell is exposed to cytochalasin, and phagocytosis stops. Phagocytosis stopped due to: a. Membrane division b. Inability of Arp2/3 to carry out its function c. Integrin activation d. Inhibition of Rac 5. In a striated muscle cell in the absence of calcium, a myosin head had just moved towards the actin plus end, but remains unbound from actin. That myosin head has most recently a. Hydrolyzed ATP b. Bound Ca 2+ c. Released ADP

d. Released a phosphate 6. During mitosis, an ATPase inhibitor is added that results in the inhibition of movements during anaphase. What mitotic process is being impacted by this ATPase inhibition? a. The action of axonemal dynein b. The replication of the centrosomes c. Microtubule sliding d. The shortening of kinetochore microtubules 7. In the above experiment of axonal transport described in class, different bands in lane 2 represent a. An anterograde traveling motor protein complex b. Proteins traveling at different speeds c. Different lengths of polymerized microtubules d. An actin/myosin complex 8. In the same axonal transport experiment above (Q7), proteins can be visualized because a. They were run on an SDS-PAGE gel b. Of the use of radiolabelled amino acids c. Of the use of protein-specific antibodies d. They are very abundant 9. How many of the following features are shared by dynein, kinesin, and myosin? (1) a. GTPase activity b. Required during mitosis c. Are unstable d. Are secreted e. Are nuclear f. Are axonemal

10. What is the role of Ndc80 if a chromosome is capture by a microtubule from only one pole? a. To permanently stabilize the microtubule b. To release the microtubule if there is no tension c. To polymerize microtubules from the opposite kinetochore d. To recruit kinesin 5, and help transport the chromosome to the metaphase plate 11. During mitosis XMAP215 is a. Phosphorylated b. Localized with myosin II c. Highly active d. Responsible for nuclear lamin disassembly 12. What will happen if colchicine is added during anaphase-A? a. The kinetochore end of the microtubules will be protected by gamman-tubulin b. The poles will be pulled closer together c. The chromosomes will no longer move away from the metaphase plate d. anaphase-A completes normally, but cytokinesis does not occur 13. How many of the following are shared by polymerized microtubules, actin, and intermediate filaments? a. Polarity b. Use of motor proteins c. Secreted d. DNA binding e. Are transmembrane 14. Which representsthe free dimers in solution in the above graph? a. A b. B c. C d. D 15. Referring to the same above graph (Q14) to the Cc a. Refers to only the (+) end of the growing actin filament

b. Only refers to G-actin in the ATP form c. Depends on temperature d. Alters with the addition of polymerizing enzymes 16. During the vesicular transport seen with yeast budding a. Actin is capped by CAPZ b. Actin is capped by tropomodulin c. myosin-V aids in positioning of the nucleus d. Cytokinesis is responsible for bud constriction 17. During chemotaxis a. The chemotactic receptor is found only on the leading edge of the cell b. Formin activation occurs around the entire surface of the cell c. Actin is assembled at the cell end near the chemotactic signal d. Stress fibers support the nuclear membrane 18. As the migrating cell in the above picture is extending a lamellipodium a. Integrins are found in this lamellipodium b. RDG sequences are found in this lamellipodium c. ECM proteins are found in this lamellipodium d. All of the above 19. The same migrating cell in the above (Q18) diagram a. Contains no intermediate filaments b. Currently has 5 adherens junctions c. Is activating Arp2/3 d. Cannot undergo anterograde transport 20. During mitosis centrioles replicate and become components of the mitotic apparatus. A difference between a centriole found in a mitotic, from that in a non-mitotic cell is that a. In non-mitotic cells centrioles are not associated with a MTOC b. Only in mitotic cells are centrioles made of triplet microtubules c. In mitotic cells centrioles move during anaphase d. In mititic cells centrioels are dynamic 21. You express augmin protein conjugated to GFP in a population of animal cells. What fluorescence pattern do you expect to see? a. Many points of fluorescence that delineate the cell membrane b. One bright point of fluorescence near the nucleus c. A ring of fluorescence, but only in mitotic cells d. Many points of fluorescence in between the trans golgi and cell membrane

22. Epithelial cels in your trachea use cilia to constantly “sweep” dust and other particulates out of your respiratory system. This clearing function is dependent on a. Parallel microtubules b. Proper axonal organization by 9 MTOCs c. Proper cargo recognition by the dynactin heterocomplex d. Cleavage of nexin to facilitate sliding 23. The myosin II thick filaments and their organization with parallel actin thin filaments in striated muscle requires a. Myosin positioning by titin b. Actin capping at the Z-disk by tropomodulin c. Dystrophin capping actin at the Z-disk d. Sarcoplasmic reticulum coating and stabilizaion of the myosin thick filaments 24. A cell expressing a5B1 integrin is migrating in one tissue, but stops migrating when it reaches a new tissue. Migration stopped because a. There is no laminin substrate in the new tissue b. There is no fibronectin substrate in the new tissue c. Cells in the new tissue do not express a5B1 integrin d. The new tissue does not contain any integrins 25. The extracellular matrix can regulate a. Cell survival b. Ciliary beating c. Microvili function d. All of the above 26. Epithelial cell function depends on difference in the cell’s apical and basal surfaces. If such a sheet of cells is treated such that they lost all of their homophilic cell adhesion molecules, but these cells still maintained their apical and basal difference, such differences could have been sustained by a. Actin circumferential belts b. Cell-cell integrin adhesion c. JAM and occludin function d. ECM adhesion 27. A mesenchymal cell migrating on a collagen substrate a. Requires actin polymerization and depolymerization b. Is utilizing hemidesmosomes linked to the ECM c. Is maintaining its shape using adherens junctions d. Requires intermediate filament motors 28. Which of the following molecules are common to BOTH desmosomes and hemidesmosomes? a. Integrins b. Microtubules c. Microfilaments d. Intermediate filaments 29. With regards to a skeletal muscle sarcomere, which of the following is not correct? a. The A band represents the actin thick filament

b. Z disks are brought closer during contraction c. The sarcomere is a repeating unit d. The actin (+) end is at the Z-disk 30. Karyokinesin and cytokinesis a. Make up the mitotic apparatus b. Together make up mitosis c. Occur only in gonads d. Occur during interphase prior to the replication of the centrosome 31. During extravasation much must occur to allow a cell to leave the bloodstream and enter the surrounding tissue. Which of the following is NOT required for extravasation to occur? a. The activation of heterophilic cadherin adhesion molecules b. Cell polarization c. Endothelial cell exocytosis d. Recognition of leucocyte cell-surface sugars by endothelial cell selectins 32. With regards to the above diagram, what is the arrow pointing to? a. Tropomodulin b. Myosin - binding site c. Ca2+ - binding site d. Troponin 33. The presence or absence of calcium in the above diagram is regulated by a. Anterograde neuronal transport b. Retrograde neuronal transport c. Changes in t-tubule membrane polarity d. Rapid golgi exocytosis

34. Cadherin is a transmembrane protein, one of its protein domains can a. Bind to laminin b. Bind to cytoplasmic celsius c. Interact with its N-CAM partner on another cell d. Be linked with the cytoskeleton 35. Which of the following facts about centroles is true a. Are composed of 3 barrels of microtubules b. Are found in plant centrosomes c. Directly polymerize microtubules d. Are made of triplet microtubules 2013 1. In which of the following do ECM proteins NOT play a role? a. Binding of cells in tissues b. Cell movement c. Modulation of ligand receptor interaction d. External fluid pressure e. Cadherin dimerization 2. During dilopodia extension, addition of palloidincytochalasin would directly impact a. Fibronectin localization b. The localization of integrins to the leading edge of the cell c. The ability of the nucleus and locomotor signals d. The extension of cilia e. Tau localization 3. Identify the structure below a. Microvili b. Desmosome c. Focal adhesion d. Hemidesmosome e. Stress fiber 4. A cell is migrating from the left to the right due to a local cAMP source (consider the “right” the front of the cell). Chemotaxis is driving this directionally and is likely related to a. Localized cAMP receptor only at the front of the cell b. Cdc42 activated on the right side of the cell

c. Rho activated on the right side of the cell d. Both a and b e. Both b and c 5. During mitosis in budding yeast one observes that sister chromatids do not move towards the poles during anaphase A. this lack of movement could be due to a. Inhibition of myosin V function b. Inhibition of kinesin function c. Stabilizaiton of microtubules d. Laminin miss-localization e. Centrosome activation 6. As the nerve cell sends a depolarization signal to the t-tubule in a skeletal muscle cell, the myosin in the thick filaments of that muscle cell are likely a. Phosphorylated b. In the rigor state c. Bound to the plasma membrane d. Forming a bipolar structure e. Forming an arrowhead shape that point to the minus end of the actin 7. Which is a feature of intermediate filaments? a. About 10 mm in diameter b. Are very elastic c. Support membranes d. Very dynamic e. Involved in organelle transport 8. Which features are shared by both microvili and filopedia a. Are composed of microtubule bundles b. Are membrane projections c. Are involved in cell migration d. Form focal adhesions e. Forms desmosomes 9. During mitosis Xmap215 a. Activity increases b. Activity decreases c. Is found localized to the centrosome d. Is bound to the kinetochore e. Both A and D 10. Intermediate filaments a. Are regulated by phosphorylation b. Are composed of polar tetramers c. Require active transport for their polymerization d. Play an important role in ER to golgi anterograde transport e. Stabilize the spindle during anaphase A 11. Axoneme bending requires a. Tau function b. Microtubule dynamics

c. Nervous depolymerization d. Prevention of microtubule sliding e. Lysis of dynein 12. During mitosis many checkpoints ensure that crucial steps are carried out properly. Phosphorylation and de-phosphorylation of proteins ensure that events such as DNA replication and sister chromatid segregation occur with extremely high fidelity. While karyokinesis and cytokinesis share many characteristics. What is one difference between them? a. Karyokinesis requires motor proteins while cytokinesis does not b. Karyokinesis utilizes cytoskeletal components that have polarity while cytokinesis does not c. Cytokinesis can be inhibited by drugs while karyokinesis cannot d. Cytokinesis requires cytoskeletal element depolymerization while karyokinesis does not e. Karyokinesis involves two cytoskeletal organizing centers while cytokinesis does not 13. Epithelial sheets require many junctional and adhesion structures to function together. Which of the following would not impact epithelial cell function a. Excess cytoplasmic calcium b. Removal of cadherins c. Prevention of focal adhesion formation d. Removal of integrins e. Both b and d 14. During a study using cultured neuronal cells a student discovers that the cells grow and form a tight sheet with each other in vitro. Upon further investigation, it is discovered that the addition of EDTA, which removes free calcium from the media, did not affect the integrity of the epithelial sheet. From this study, we can deduce a. The cells have no functioning gap junctions b. The cells are held together by Ig-superfamily CAMs c. Calcium inhibits cell migration d. Calcium inhibits cadherin function e. Neurons do not contain claudin 15. A common feature of actin filament growth in both non-migrating and migrating cells is a. Activation of formin b. The need of cAMP receptor on all areas of the plasma membrane c. The regulation of Arp2/3 by coffin d. Microvili extension e. Cortical LAP2 16. Selectin recognition of oligosaccharides during extravasation requires a. Carbohydrates on the leucocyte cell b. Migration on the endothelial cell c. Cadherin binding between the leucocyte and the endothelial cell d. Cadherin binding between leucocytes e. Integrin binding between leucocytes

17. How many of the following play a role in sarcomere function and/or muscle contraction a. Troponin b. Titin c. Actin d. Myosin e. CapZ f. Desmoglein g. NFL h. Vimentin i. Dystrophin 18. A cell is treated such that thymosin could no longer function. As a result a. The microtubule network would grow uncontrollably b. The centrosome would be inhibited but basal bodies would continue to function c. Actin would likely polymerize at both its minus and plus ends d. Actin could not branch e. The sarcoplasmic reticulum could not release its calcium 19. A cell produces many filopodia. This could be due to a. Dominant active Cdc42 b. G-actin concentration above 0.12 µM c. Treadmilling d. Increased absorptive needs of the epithelial cell e. Inhibition of Arp2/3 20. A migrating cell expressing a1B1 stops its movement. This could result due to a. The absence of collagen on the cell’s surface b. Lack of integrin in the ECM in the path of the cell c. Lack of RGD peptides on the cell surface d. No laminin in the ECM e. None of the above 21. Cytoplasmic streaming a. Is common in large cells b. Often utilizes myosin-V c. Does not require actin polarity d. Both a and b e. Both b and c 22. During the contraction of a muscle cell a mutation occurs such that calcium pumps no longer function as a result high levels of calcium remain in the cytoplasm and bathe all parts of the sarcomere. With this persistent availability of calcium a. Myosin’s binding site on actin is continuously available for myosin binding b. The muscle would remain in the rigor state c. Myosin would take one power stroke then remain waiting for ATP hydrolysis d. The distance between the Z-disks would expxand e. Troponin would continue to stabilize the minus end on actin

23. The arrow in the below graph points to the line that represents a. The length of the growing tubule b. Tubulin dimers c. GDP bound B-tubulin d. GTP bound-B-tubulin e. Tubulin monomers 24. How many of the following are shared between basal bodies and centrioles? a. Stability b. Triplet microtubules c. Are found in the centrosome d. Contain gamma-tubulin e. Found in plasma 25. With respect to the two microtubule severing proteins described in lecture, stathmin and kinesin-13 both a. Require ATP hydrolysis to function b. Are motor protein family members c. Can contribute to the destabilization of microtubule ends d. Both a and c e. A b and c 26. During microtubule retrograde transport a. Dynein is utilizing the dynactin heterocomplex to bind cargo b. Stem domains are hydrolyzing ATP c. Stem domains are hydrolyzing GTP d. The minus end of the microtubule is depolymerizing e. myosin-V can transport a variety of cargo 27. Cell-cell adhesion complexes are associated with specific cytoskeleton systems/ which of these adhesive complexes are linked to intermediate filaments? a. Focal adhesions b. Adheres junctions c. Desmosomes d. Gap junctions

e. Tight junctions 28. Seperation of spindle poles during anaphase B utilizes which of the following? a. (+) end directed microtubules motors at the cell membrane b. (+) end-directed microtubule motors at the kinetochore c. (-) end directed microtubule motors on overlapping polar microtubules d. (+) end-directed microtubules motors on overlapping polar microtubules e. Both a and c 29. Which cell-surface protein binds to the tripepetide sequence Arg-Gly-Asp? a. Integrin b. Collagen c. Lamin d. Fibronectin e. Both b and d 30. The plasma membrane of eukaryotic cells is supported by a. Actin filaments b. Microtubules c. Lamins d. Clathrin e. Myosin II 31. With respect to cell migration, which is the correct sequence of events? a. Rac activation at the front of a cell allows Rho activation of Arp2/3 and subsequent Cdc42 activation and myosin activation b. Cdc42 activation at the front of a cell allows Rac activation of Arp2/3 and subsequent Rho activation and myosin activation c. Rho activation at the front of a cell allows Rac activation of Arp2/3 and subsequent myosin activation by Arp2/3 d. Cdc42 activation at the front of a cell allows WASp activation of Rho and subsequent actin activation e. Rac activation at the front of a cell allows WASp activation of Arp2/3 and subsequent Rho activation 32. With respect to actin polymeriation, when there is ample G-actin in the ATP form, the presence of nuclei (short F-actin polymers) will a. Decrease the time needed to reach steady state b. Increase the time needed to reach steady state c. Decrease the critical concentration of the plus d. Increase the critical concentration of the plus e. Inhibit polymerization 33. A group of epithelial cells that contain circumferential belts constrict at their apical (top) surface during early development to help form the central nervous system. How would treatment of these cells with calchine affect this constriction? a. The cells would dissociate b. The cells would constrict normally c. The cells cells would constrict basally (at their bottom) d. The cells would not constrict

e. The cells would begin to migrate 34. Microtubules within a dendrite are composed of ______ protofilaments a. 10 b. 13 c. 23 d. 33 e. 9+2 35. The contractile ring is centered between which of the following? a. The leading and trialing and cilia b. The mitotic poles c. Myosin I and myosin V d. Opposite + TIP MAPS e. The Z-disks 2012 1. In the above diagram of microtubule dynamics, how many of the following events could have occurred at point A to result in the above effect? a. Addition of cofilin b. Addition of colchicine c. Addition of EB1 d. Addition of MAP2 e. Decrease in temperature 2. Anterograde transport within plant cells a. Cannot occur as plants do not have membrane bound organelles b. Cannot occur as plants do not have centrosomes c. Cannot occur as plants do not have axons d. Occurs in a microtubules dependent fashion e. Can only occur in cells that chloroplasts

3. Cohesion has just released chromosomes and allowed their separation. From this we know that a. The cell is just entering mitosis b. The yeast nucleus is being transported to the growing bud c. The kinetochore microtubules are beginning to depolymerize d. MAP phosphorylation is causing actin instability e. The chromosomes can now shift forward towards the leading edge of the migrating cell 4. A sliding filament assay is being used to investigate cytoskeletal protein dynamics. A protein of interest is bound to the glass slide, and cytoskeletal polymers added. Experiments reveals that the movement of these cytoskeletal elements require the hydrolysis ATP, but not GTP. from the possibilities listed below, we can conclude that the protein bound to the slide is a. An alpha-beta tubulin dimer b. Kinesin c. Rho d. Formin e. Actin 5. As you sit writing this midterm your muscle cels are a. All in rigor b. Actively migrating to facilitate finger movement c. Utilizing Capz to stabilize actin d. Decreasing the size of their A-bands to facilitate finger movement e. None of the above 6. Scientists are studying the dynamics of microtubule polymerization. Their polymerization conditions always provide the energy (GTP) requirements that are needed. They determine the critical concentration of purified tubulin dimers that is required to form polymers at room temperature. With the dimers at this Cc they then lower the temperature to 4 degrees celsius and add gamma-TuRC. They then begin to slowly raise the temperature. As the temperature increases a. The gamma-TuRC will form a centrosome b. Microtubules will polymerize at a temperature below room temperature c. The dimers, with gamma-TuRC at their (-) end will only form polymers once 37 degrees celsius is reached d. Growth will occur at both the (+) and (-) ends, with the (+) end growing faster e. The stabilized microtubule polymers that were present at 4 degrees celsius would elongate by attaching end to end 7. The role of dystrophin in muscle cells is to a. Stabilize the sarcomere b. Link the cytoskeleton to cell surface transmembrane proteins c. Stabilize the plasma membrane d. Crosslink the actin network e. Link spectrin to ankyrin

8. From the diagram of the above cell, we know that the cell a. Is undergoing extravasation b. Has formed 6 hemidesmosomes c. Has formed tight junctions d. Contains stress fibers e. Is expressing P-selectin 9. Which does NOT occur during muscle contraction? a. The size of each Z-disk deceases b. The I-band decreases in size c. Calcium is released from the sarcoplasmic reticulum in response to membrane depolarizaiton d. myosin-II binding to actin is regulated by tropomyosin e. Microfilaments are stabilized by nebulin 10. Myosin-5 plays a pivotal role in a. Contractile rings function b. The localization of formin during yeast budding c. The transport of formin during yeast budding d. Organelle movement in plant cells e. DNA replication during yeast budding 11. A mutation in Cdc42 will effect a. Dynein function at the rear of a migrating cell b. Membrane extension at the front of a migrating cell c. Hemidesmosome function at the rear of a migrating cell d. Lamin stability at the nuclear envelope e. Desmosome function at the front of a migrating cell 12. Which is not a characteristic of cytoskeletal motor proteins? a. Require energy for movement along the cytoskeleton b. Multi-directional movement c. Contain head domain structures that bind the cytoskeleton d. Can exist as dimers e. Are translated in the cytoplasm 13. Spectrin a. Can bind ankyrin b. Aids in forming cortical networks c. Can crosslink actin fibers in a similar way as filamin

d. Is found in red blood cells e. All of the above 14. Removal of JAM from a keratin expressing cell sheet would result in a. Decreased cell migration b. Increased epithelial permeability c. Decreased ciliary beating d. Increased adherens junction binding e. Decreased focal adhesion binding 15. Examination of a cell revealed that it contained NFH, tau, and lamin. We can conclude that this cell a. Can produce hair b. Can respond to cAMP and migrate c. Is undergoing karyokinesis d. Has bundles of microtubules e. Contains microvili 16. Which is not a proprety of cadherin molecules? a. Contain a transmembrane domain b. Contain a cytoplasmic domain c. Can be linked to intermediate filaments d. Can bind RGD e. Can be linked to actin 17. Proteoglycans a. Are very elastic b. Are covalently linked to NCAM molecules c. Are hydrophilic d. Increases nuclear volume e. Have homophilic binding that is mediated via serina phosphorylation 18. Which of the following statements is true regarding mesenchymal cells? a. They can use a5B1 integrin to bind to RGD sequences on laminin b. Their integrin can be found to GFAP c. Their integrins may be bound to actin d. They always form hemidesmosomes e. Both a and d 19. Which of the following does NOT occur during mitosis? a. MAPs are phosphorylated b. lamin is phosphorylated c. A contractile ring is formed d. I-bands decrease in size during anaphase A e. myosin-I plays an important role in anchoring the actin cytoskeleton to the plasma membrane 20. Dominant active cdc42 will result in a. Excess filopodia b. Excess focal adhesions c. Reduced actin bundles

d. Reduced focal adhesions e. Reduced myosin-5 transport 21. What is a key difference between kinesin-1 and -13? a. Only kinesin-1 utilizes ATP b. Only kinesin-1 utilizes GTP c. Kinesin-13 does not have head domains d. Kinesin-13 does not bind cargo e. Kinesin-1 does not have light chains 22. Fraying of the microtubule (+) end is associated with a. Lack of GTP cap b. Excess taxol c. Lack of stathmin d. Axon signalling e. Lack of CapZ 23. Axoneme bending is dependent on a. Tau protein stability b. Anti-parallel microtubules c. Retrograde motor movement d. Basal body depolymerizaiton e. None of the above 24. Microtubules a. Have polarity b. Can be 100s of µM long c. Are not found in plants d. Both a and b e. Both a and c 25. Which is NOT true of centrioles? a. Are found in centrosomes b. Are composed of triplet microtubules c. Can replicate d. Are stable e. Facilitate polymer growth through dimer addition to their (+) end 26. During normal mitosis all of the following have to occur prior to and during metaphase, except: a. Microtubule polymerization and depolymerization b. The utilization of motor proteins c. Capture of the centromere by centromere microtubules d. Capture of all chromosomes e. Established of 2 poles 27. An epithelial sheet of sheets is treated with a chemical that raises free calcium levels in the cytoplasm. As a result these cells will a. Have impaired gap junction function b. Have impaired N-Cad function c. Have increased E-Cad binding

d. Shorten their sarcomeres e. Increase their apical/basal height 28. A short piece of F-actin that is coated with S1 myosin a. Can act as a nucleating centre b. Will depolymerize with the addition of taxol c. Can still be cleaved by katanin d. Is required during cytokinesis e. Has no polarity 29. During extravasation a. P-selectin binds to a specific carbohydrate b. Red blood cell migration is triggered c. Epithalial cell migration is triggered d. Integrins are used as homophilic adhesion molecules e. Cadherin binding facilitates cell recognition 30. The extracellular matrix a. Is made up of many types of secreted proteins b. Is found on the basal side of epithelial cells c. Can be bound by specific transmembrane proteins d. Is found outside of cells e. All of the above 31. A characteristic of a mesenchymal cell is the a. Lack of lamin intermediate filaments b. Presence of stress fibres c. Lack of integrin d. Presence of vimentin e. 2 of the above 32. How many of the following are required for adheres junction function? a. Cadherin b. Actin c. Calcium d. Selectin e. Keratin f. Lamimin 33. A cell is migrating on a collagen substrate. From this we can deduce that the cell a. Is expressing a1B1 integrin b. Is expressing RGD c. Contains NFM d. Contains hemidesmosomes e. Contains laminin 34. As actin is cortical it a. Plays a key role in nuclear localization b. Is repsonsible for positioning the centrosome c. Can mediate cell shape d. Regulates axoneme stability

e. Cannot interact with the membrane 35. Flagella and cilia differ in a. Cytoskeletal components b. Motor protein usage c. Size d. A and b e. A and c 2011 1. Tight junctions a. Are typical of epithelial cells b. Are typical of axons c. Link nerves and muscles together d. Link the axoneme to the basal body e. Contains desmoglein 2. A migrating cell expression a6B1 integrins on its surface suddenly stops migrating. This end of migration could be due to a. The presence of laminin b. the presence of ECM c. The activation of Rac by Cdc42 d. The inhibition of kinesin 5 function e. The overexpression of thymosin 3. Which of the following occur during prophose? a. All chromosomes are caught by one pole b. All chromosomes are caught by both poles c. Nuclear envelope breaks down d. Centrosomes replicate e. Polar microtubules depolymerize 4. XMAP215 activity is related to a. Axonemal stability b. Centriole stability c. Doublet stability d. Spindle stability e. Triplet stability 5. Which of the following is a typical function of the actin cytoskeleton? a. Nuclear transport b. Chromosome transport c. Retrograde transport d. Cortical transport e. Axonemal transport 6. You are performing an in vitro experiment with actin filaments in which you are trying to identify an unknown protein by measuring its effect on actin polymerization. You add ATP-bound G-actin subunits at a concentration of 0.8 µM together with your unknown

protein. When you observe your filament you see growth only at the end to which S1 arrowheads are pointing. From this you conclude that your unknown protein is a. CAPZ b. Cofilin c. Taxol d. Filamin e. Troponin 7. In the same experiment in question 6 above, you then add active formin to the mix. As a result, you now expect to see a. No change b. Growth at both ends c. Growth at the end away from where the S1 arrowheads are pointing d. Depolymerization at the end away from where the S1 arrowheads are pointing e. Depolymerization at both ends 8. Epithelial cells grown using appropriate media in vitro form cell adhesions similar to those they form in tissues. If the media that these cells were grown in was changed such that the calcium it contained was now removed, how would these cells react to the lack of calcium in the media? a. The functions of their desmosomes would be altered b. The functions of their gap functions would be altered c. The function of their tight junctions would be altered d. The functions of their focal adhesions would be altered e. The functions of their microvili would be altered 9. With respect to cell-cell and cell-ECM adhesions which of the following is true? a. They both use homophilic adhesions b. They both require ATP hydrolysis c. Both require membrane fusion d. Both require cell microvili interactions e. Both can have links to the cytoskeleton 10. A mitotic cell will NOT have which of the following? a. Dynamic microtubules b. Stress fibers c. Phosphorylated lamin A d. Membrane associated myosin-1 e. Membrane associated dynein 11. During cell migration, polymerization of actin drives the cell membrane forward, while at the same time the opposite end of the same microfilament is being depolymerized. From these facts we know that a. The + end is capped b. The filament is treadmilling c. Cofilin is acting at the + end d. Rho is active at the - end e. The troponin on the actin filament has shifted 12. How many of the following can directly influence microtubule polymerization?

a. Dimer concentration b. Temperature c. MAP polymerase d. dynein e. Profilin f. Rho 13. In the above diagram, how many of the following are true of the structure indicated by ii? a. It is extracellular b. It prevents passage of molecules c. It forms part of a desmosome d. It is directly bound to tubulin e. It contains cadherins 14. In the same diagram above, we know that these cells a. Have cilia b. Lack microtubules c. Are polar d. Are migrating e. Lack keratin 15. In the same diagram above, how many of the following are shared by i and ii? a. They are composed of microtubules b. They are basal c. They facilitate migration d. Their function is calcium dependent e. They are poes 16. What is common to microfilaments, microtubules, and intermediate filaments? a. They are dynamic

b. They require nucleotides c. They form networks d. They are motor proteins e. They are polarized 17. A mutation is discovered in red blood cells where their form is unusual and not their typical bi-concave shape. One reason for their altered shape may be a. Non-functional ankyrin b. The presence of profilin c. Non-functional tropomyosin d. The presence of Tau e. Non-functional dynactin heterocomplex 18. A polymerization assay for the Cc+ of actin is graphed above. Relative to the above Cc+ position, where would you find the Cc-? a. A b. B c. C d. D e. The Cc- will be the same as the Cc+ 19. In the same graph above, the line indicated by the question mark (?) represents what? a. The pool of free dimers b. The length of the microfilament c. The free nuclei d. S1 concentration e. None of the above 20. gamma-TuRC a. Is found in all MTOCs b. Often associated with the + end c. Identical to CAPZ

d. Pericentriolar e. Cortical 21. A common feature of cytoskeletal associated proteins is to help maintain cell shape and the integrity of the cell membrane. Accordingly which of the following statements is false? a. Dystrophin binds to a transmembrane protein complex b. Ankyrin functions exclusively through filamin c. Integrins are common in migrating and non-migrating cells d. Adaptor proteins link intermediate filaments and microfilaments to cadherin e. Microtubules, intermediate filaments, and microfilaments all play a role in maintaining cell shape 22. How many of the following will directly disrupt cell migration if their function is inhibited? a. Integrins b. Myosin c. Lamin d. Rho e. Connexin 23. Which of the following is not a property of a basal body? a. Contains triplet microtubules b. Is considered a centrosome c. Is stable d. Is composed of protofilaments e. Is polar 24. How many of the following are characteristics of myosin II? a. 2 heavy chains b. Bi-polar c. Found in I-band d. Vesicle transport e. Retrograde transport 25. With regards to the mitotic apparatus, which of the following is NOT true a. It is cytoskeletal b. It is composed of polar, kinetochore, and astral microtubules c. It is organized by polar, kinetochore and astral MTOCs d. It provides the forces needed for chromosome movement e. It is not present during interphase 26. During mitosis, an ATPase inhibitor is added for a brief period that results in the inhibition of movements during anaphase B. what process is being impacted by this ATPase inhibition? a. The action of astral dynein b. The replication of the centrosomes c. Microtubule sliding d. A change in Cc e. Both a and c 27. A cell that contains vimentin would also be expected to contain

a. Keratin b. Desmosomes c. Focal adhesions d. Desmin e. Axonemes 28. During microtubule fraying of the + end, instability results due to the a. Absence of gamma-tubulin b. GTPase activity of beta-tubulin c. Hydrolysis of the dimer d. Action of dynactin e. Inhibition of fimbrin 29. In a muscle cell, what is the state of the myosin head when calcium is first released from the sarcoplasmic reticulum to start a contraction? a. It is in the rigor state b. It is finishing the power stroke c. It is bound to ATP and tropomyosin d. It has hydrolyzed its bound ATP e. It has released its phosphate and awaits binding to actin 30. Brefledin-A is a drug used in cell studies that inhibits transport from the ER to the golgi. Accordingly we know that this drug is actin upon a. Microfilament depolymerization b. Anterograde transport c. +TIP localization d. Centrosome replication e. Myosin I function 31. Arp2/3 in non-migrating cells a. Cross-links existing microfilaments b. Caps the + end of a growing microfilament c. Is directly regulated by Rho d. Helps form a branched actin network e. Cross-links existing lamin filaments 32. GEF and GAP are proteins involved in facilitating signalling pathways that utilize GTP in many cells. If GTP function is inhibited in a migrating cell, cell movement would be inhibited because a. The G-actin would not be in the correct state b. Thymosin would not be correctly localized to the leading membrane c. Formin function would be inhibited d. Myosin within contractile bundles would not be able to function e. The trailing tail would not be able to release its focal adhesion 33. What is not common to cadherin and NCAM? a. Transmembrane domain b. They are homophilic c. Cytoskeletal association d. Extracellular domain

e. All of the above are common to both 34. A migrating cell does not require a. Microtubule dynamic instability b. Integrin adhesion c. Intermediate filament + end stability d. Actin and cofilin activity e. ATP bound G actin 35. Which is true with respect to the sliding that occurs with both axonemal and polar microtubules a. They both involve motors that have a bi-polar structure b. They both require microtubule depolymerization c. They both require ATP hydrolysis d. They both involve parallel microtubules e. None of the above are true