BIO 465 - CH 23

1. 1Which of the following does not play an important role in the establishment of axon tracts and in growth cone navigation?

   1. ACell adhesion molecules
   2. BThe establishment of cell polarity
   3. CCytoskeletal proteins
   4. DSecond messenger systems
   5. EAll of the above do play an important role
2. 2The first step in developing the adult morphology of a neuron is....

   1. Ainsertion of voltage-gated ion channels into the cell membrane.
   2. Bestablishment of an apical/basal cytoskeletal polarity.
   3. Cthe appearance of an axon as the first protrusion from the cell body.
   4. Dthe appearance of an apical dendrite as the first protrusion from the cell body.
   5. ENone of the above are observed during morphological development.
3. 3If one followed a growth cone through a "decision point" at which it made a large, abrupt turn (e.g. 90 degrees), one would observe the growth cone....

   1. Afiring barrages of action potentials to help it electrically burrow into the new tissue.
   2. Bbundling numerous filopodia into a battering-ram shape in order to penetrate the tissue in the new direction.
   3. Cgenerating a large semi-circular lamellipodium to chemically sample the environment.
   4. Dextending numerous filopodia, as if searching for a new direction.
   5. Eforming a right-angle, with its forward neurotic pointing in the direction toward which the following axon will grow.
4. 4Elongation of the axon proper (as it trails the growth cone) is most directly a consequence of....

   1. Aactin polymerization.
   2. Btubulin polymerization.
   3. Ctubulin depolymerization.
   4. Dfilopodia withdrawal.
   5. Eactin depolymerization.
5. 5Actin and tubulin dynamics in growth cones are influenced or regulated by...

   1. Aintracellular calcium.
   2. Bvoltage-gated calcium channels.
   3. Cintracellular calcium stores.
   4. DTRP channels.
   5. EAll of the above.
6. 6Which of the following does not contribute to the laterality of retinal ganglion cell central projections?

   1. AExpression of the Zic2 transcription factor
   2. BExpression of EphB1 receptors in temporal retinal axons
   3. CExpression of ephrin B2 ligand on midline glial cells
   4. DAttraction of EphB1 axons to the ephrin B2 ligand
   5. EAll of the above contribute to the establishment of visual laterality.
7. 7Axon guidance cues can affect...

   1. Aactin and tubulin dynamics.
   2. Bthe complement of receptors and channels at the surface of the plasma membrane.
   3. Cthe expression of different neural genes.
   4. DAll of the above.
   5. ENone of the above
8. 8Extracellular matrix molecules serve as ligands for....

   1. Aintegrin receptors.
   2. Bunc5 and robo.
   3. CL1.
   4. Dcadherin.
   5. Eplexin.
9. 9The chemoattractant signaling molecule netrin...

   1. Ais present only in birds and mammals.
   2. Bis named for nectar, because it has been equated to a nectar of the gods for its trophic effects.
   3. Ccan signal by binding to the DCC ("deleted in colorectal cancer") receptor.
   4. Dis present in very high quantities and thus attracts many axons.
   5. Eis an integral, or fixed, component of the extracellular matrix.
10. 10Semaphoring bound to cell surfaces or the extracellular matrix...

    1. Abind to robo and slit to prevent decussation of axons.
    2. Bcause growth cones to collapse and axons to stop growing.
    3. Cproduce elevated potassium levels in most growth cones.
    4. DAll of the above.
    5. ENone of the above.

11. 11Roger Sperry's chemoaffinity hypothesis....

    1. Aarises from the fact that frog axons are able to regenerate.
    2. Bis supported by the orderly rein nervation of the frog optic tectum by regenerating retinal ganglion cells.
    3. Ccorrectly predicted that each optic tectal neuron-retinal axon pair would have a unique molecular lock-and-key recognition signal.
    4. Dwas based upon his discovery of cell adhesion molecules in the optic tectum.
    5. EAll of the above.
12. 12The two molecules that aid the molecular construction of most CNS synapses by recruiting pre- and post-synaptic machinery are.....and........

    1. Aneurexin; neuroligin
    2. Bcadherin; protocadherin
    3. CSynCAM; cadherin
    4. Dephrin; the Eph receptor
    5. Enetrin; ephrin
13. 13Neurotrophic factors...

    1. Adeliver glucose to sustain cells.
    2. Bprovide hundreds of directional cues to guide axons to correct target locations.
    3. Callow the CNS to produce and maintain a large number of excess neurons.
    4. Ddeliver ATP to sustain cells.
    5. Eplay a role in adjusting the size of neuronal populations to an appropriate number.
14. 14Neurotrophic factors...

    1. Aensure that the correct numbers of axons innervate each target cell.
    2. Bensure that each axon innervates the correct number of target cells.
    3. Care involved in the elimination of excess synaptic connections.
    4. Dinfluence the degree of divergence and conference in synaptic innervation.
    5. EAll of the above.
15. 15Which statement about competitive interactions during the innervation of the neuromuscular junction is false?

    1. AThe eventual mononeuronal innervation results from a "winner-take-all" process in which the losing axon's input begins to lose strength, resulting in receptor loss and then further weakening.
    2. BPolyneuronal innervation can be visualized with stains that reveal the presynaptic terminal and postsynaptic receptors.
    3. CBlocking action potentials with TTX prevents the reduction of polyneuronal innervation.
    4. DBlocking acetylcholine receptors with curare leads to the loss of all synaptic inputs.
    5. EReduction of polyneuronal innervation does not result from active displacement of the "losing" input by the eventual "winner"
16. 16The reported correlation between the number of dendrites and the number of innervating axons in adult rabbit ciliary ganglion cells....

    1. Awas based upon a behavioral read out of ciliary ganglion function.
    2. Bserved mainly to confirm similar findings established for CNS neurons.
    3. Cdemonstrated that neurons cannot make more postsynaptic sites than they have dendrites.
    4. Dsuggested that local competition between two nearby synapses results in the elimination of one of them.
    5. EAll of the above.
17. 17A key observation leading to the discovery of trophic factors was....

    1. Athat all neurons appeared to release a self-stimulating trophic factor.
    2. Bthe effect of mouse tumor cells on axon growth in mice.
    3. Cthe chance observation of neurons with extremely fat axons growing at remarkable speeds.
    4. Dthat neurons do not require trophic factors if hey receive sufficient glucose and oxygen.
    5. Ea mouse tumor that rapidly killed neurons, the effect of which was blocked by an activity later identified as NGF.
18. 18After the discovery of NGF, the next discovery of a neurotrophic factor (BDNF) did not occur for a number of decades because....

    1. ABDNF is not a protein and was undetectable in the assays being used.
    2. BBDNF is virtually indistinguishable from NGF.
    3. CBDNF is present in vanishingly small amounts in normal tissues.
    4. DBDNF affects only a very small subset of neurons in cortex.
    5. Eit was assumed that there were no other neurotrophic factors.
19. 19Which of the following statements about neurotrophin activation of tyrosine kinase (Trk) receptors is true? [use textbook description here]

    1. ABDNF and NT-4/5 both activate TrkA.
    2. BNT-3 activates TrkC and co-activates TrkA.
    3. CNeural growth factor activates TrkA and TrkC.
    4. DBDNF and NT-4/5 both activate TrkB.
    5. EAll four neurotrophins activate all three Trk receptors.
20. 20Which of the following statements about the p75 receptor is false?

    1. AIt can initiate the c-jun transcriptional activation pathway.
    2. BIt is identical to the Trk receptors in terms of molecular structure and signaling pathways.
    3. CIt is best activated by "unprocessed" neurotrophins.
    4. DIt can act through Rho GTPases to regulate neurite outgrowth.
    5. EIt can be activated by the same neurotrophins that activate Trk receptors.

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BIO 465 Quiz on BIO 465 - CH 23, created by Olivia Feagles on 03/05/2015.

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