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TLS Online TPP Program

#Question id: 1244

Which type of experimental evidence shows that the intrinsic GTPase activity of the Gα subunit is important for terminating effector activation?

#Unit 4. Cell Communication and Cell Signaling

  1. A nonhydrolyzable GTP analog that can bind to the Gα subunit but cannot be hydrolyzed by the intrinsic GTPase, thereby activating the effector protein longer upon ligand-induced activation of the receptor. 

  2. A nonhydrolyzable GTP analog causes displacement of GDP with the modified GTP resulting in continuous activation of the receptor because the bound GTP analog cannot be hydrolyzed to GDP.

  3. A dominant active (constant activity) GEF causes stimulation of the effector protein for longer upon ligand-induced activation of the receptor.

  4. A dominant negative (no activity) GEF causes stimulation of the effector protein for longer upon ligand-induced activation of the receptor.

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TLS Online TPP Program

#Question id: 11224

#Unit 7. System Physiology – Animal

How could you increase the magnitude of excitatory postsynaptic potentials (EPSPs) generated at a synapse?
TLS Online TPP Program

#Question id: 11225

#Unit 7. System Physiology – Animal

What happens if twice as many inhibitory postsynaptic potentials (IPSPs) as excitatory postsynaptic potentials (EPSPs) arrive in close proximity at a postsynaptic neuron?
TLS Online TPP Program

#Question id: 11226

#Unit 7. System Physiology – Animal

At the neuromuscular junction, the neurotransmitter acetylcholine (ACh) is degraded by acetylcholinesterase. If a neurophysiologist applies the naturally occurring acetylcholinesterase inhibitor, onchidal (produced by the mollusc Onchidella binneyi), to a synapse, what would you expect to happen?
TLS Online TPP Program

#Question id: 11227

#Unit 9. Diversity of Life Forms

Mycoplasmas are bacteria that lack cell walls. Based on this structural feature, which statement concerning mycoplasmas should be true.
TLS Online TPP Program

#Question id: 11228

#Unit 9. Diversity of Life Forms

Though plants, fungi, and prokaryotes all have cell walls, we place them in different taxa. Which of these observations comes closest to explaining the basis for placing these organisms in different taxa, well before relevant data from molecular systematics became available?
TLS Online TPP Program

#Question id: 11229

#Unit 9. Diversity of Life Forms

Which is the bacterial structure that acts as a selective barrier, allowing nutrients to enter the cell and wastes to leave the cell.