How do myelin sheaths increase the speed with which action potentials are propagated along an axon?
A) They increase the permeability of Na+ ions in the plasma membrane.
B) They amplify the action potential by increasing sodium influx along the entire distance of the neuron.
C) They cause action potentials to "jump" down the axon rather than travel in a continuous path along every site on the axon.
Answer: C
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The coding regions of a gene are known as ________.
Fill in the blank(s) with the appropriate word(s).
So far, the only disease that has been globally eradicated is
A. polio. B. smallpox. C. measles. D. diphtheria.
In pea plants, round pea texture is dominant over wrinkled texture. How can you obtain true-breeding pea plants
having round peas with the least amount of work?
a. Cross plants having round peas with plants having wrinkled peas. Select round pea plants from the progeny because they are now true-breeding. b. Cross plants having round peas with other plants having round peas. Do this for multiple generations. c. Cross plants having round peas with plants having wrinkled peas. Select round pea plants from the progeny and do a testcross to determine which parental plants were homozygous dominant. d. Cross plants having round peas with plants having wrinkled peas. This will tell you which round pea plants are homozygous dominant and are thus true-breeding. e. It's not possible. You can only get true-breeding plants that have wrinkled peas.
While the transports dissolved organic nutrition molecules, such as sugars, from the leaves after photosynthesis, the transports water and dissolved minerals from the soil to the shoots and leaves.
A. tracheids; vessel elements B. phloem; xylem C. ground tissue; dermal tissue D. wood; meristem E. xylem; phloem