Some drugs modulate the activity of ion channels. For example, Novocain somewhat inhibits the opening of sodium channels. What happens to the threshold of a sensory neuron if this drug is used?
A) It will take less stimulation to reach threshold.
B) It will take more stimulation to reach threshold.
C) Threshold will not change.
D) The nerve will not function and will die off.
B
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A scientist evaluates cellular mRNA and finds a population of transcripts that do not have a 3' poly(A) tail. However, these transcripts are translated into protein. What would these proteins most likely be?
A. ribosomal proteins B. RNA binding proteins C. DNA binding proteins D. transport proteins.
Approximately 3.5 million years ago the Isthmus of Panama formed. This new landmass severed the connection between the Pacific Ocean and the Caribbean Sea. An ancestral fish population (porkfish) was split in two by this event; the two populations no longer interbreed and are two distinct species. This type of speciation is called
A. allopatric speciation. B. parapatric speciation. C. hybridization. D. sympatric speciation. E. sexual selection due to ecological variation.
In what mitotic stage does the cytoplasm divide?
A. prophase B. metaphase C. anaphase D. telophase
A child has a sore throat, headache, high fever, and a cough. A couple of days later there are white spots with a red margin on the mucous membranes of the mouth. These signs and symptoms are consistent with infection with
A. rhinovirus. B. measles virus (rubeola). C. rubella virus. D. parainfluenza virus. E. mumps virus.