Explain how neuron action potential propagation rate can be increased
What will be an ideal response?
ANSWER: Neuron action potential propagation can be increased in two ways: (1) by increasing axonal
diameter, and (2) myelinating the axon. Increased axonal diameter reduces electrical
resistance to current flow. Myelination causes an electrical current to "jump" from one
node of Ranvier to the next by saltatory conduction, which is more rapid than conduction
in an unmyelinated neuron.
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A scientist is studying a population of feral cats in his city. After ten years, he notes that—for the population of feral cats he is studying—(K–N)/K = 0
Based on this information, what can he deduce about the logistic growth curve for the population at this point in time (recall Figure 46.5)? A. The curve resembles an exponential growth curve. B. The curve is at its inflection point (i.e., the rate of growth has started to slow). C. The curve has plateaued at K. D. The curve is at its steepest point.
Populations that exhibit logistic growth still exhibit exponential growth. This statement is
a) true; populations exhibiting logistic growth go through a period of exponential growth before growth rates level off around zero b) true; logistic growth is another term for exponential growth c) false; populations exhibiting logistic show exponential growth when the population size is greater than the environment's carrying capacity d) false; exponential growth and logistic growth are characteristics of different species e) true; however this can only occur in different populations of the same organism because one population cannot exhibit both types of growth
To begin transcription, eukaryotic RNA polymerase recognizes nucleotide sequences in what region of the DNA?
a. promoter region b. initiator region c. replication origin d. terminator region e. G-C-rich region
The atria of the heart
A. are separated from each other by the interventricular septum. B. function primarily as reservoirs for blood collection. C. function primarily as the pumps of the heart. D. receive blood from the aorta and pulmonary trunk. E. have all of these characteristics