The transition from the closed to the open complex involves structural changes in the enzyme and the opening of the DNA double helix to reveal the template and nontemplate strands. This “melting” involves

A. Isomerization reaction and it does not require energy derived from ATP hydrolysis

B. Isomerization is essentially irreversible and, once complete, typically guarantees that transcription will subsequently initiate

C. Positions –11 and -2, with respect to the transcription start site.

#Question id: 11216

#Unit 7. System Physiology – Animal

When two excitatory postsynaptic potentials (EPSPs) occur at a single synapse so rapidly in succession that the postsynaptic neuron's membrane potential has not returned to the resting potential before the second EPSP arrives, the EPSPs add together producing ________.

#Question id: 11215

#Unit 7. System Physiology – Animal

If excitatory postsynaptic potentials (EPSPs) are produced nearly simultaneously through two different synapses on the same postsynaptic neuron, the EPSPs can also add together creating ________.

#Question id: 11214

#Unit 7. System Physiology – Animal

Neurotransmitters categorized as inhibitory are expected to ________.

#Question id: 11213

#Unit 7. System Physiology – Animal

An example of ligand-gated ion channels is ________.

#Question id: 11212

#Unit 7. System Physiology – Animal

The activity of acetylcholine in a synapse is terminated by its ________.

#Question id: 11211

#Unit 7. System Physiology – Animal

The following steps refer to various stages in transmission at a chemical synapse.

1. Neurotransmitter binds with receptors associated with the postsynaptic membrane.

2. Calcium ions rush into neuron's cytoplasm.

3. An action potential depolarizes the membrane of the presynaptic axon terminal.

4. The ligand-gated ion channels open.

5. The synaptic vesicles release neurotransmitter into the synaptic cleft.

Which sequence of events is correct?