Sodium and potassium ion channels have several negatively charged residues at the entry to the channel. On what basis do K+ channels specifically select for K+ ions? (In other words, why dont K+ channels enable Na+ ions to cross the membrane?)

A. ionic radius, Na+ is to small
B. energy cost, it is to energetically costly to dehydrate Na+
C. charge, Na is slightly more electronegative than K and does not interact with the channel carbonyl groups
D. charge, Na is slightly less electronegative than K and does not interact with the channel carbonyl groups
E. ionic radius, Na+ is too big

Which way do the nitrogenous bases in dna pair up? a. a and g; t and c b. a and c; t and g c. a and t; g and c d. a and a; t and t; g and g; c and c

Clues to ecological principles are given in numerous passages of the bible. a bible study of ecology actually opens the doors to better understanding of god's love and concern for the earth. use a concordance to locate bible passages associated with words concerning our stewardship of the earth. you may use a dictionary to find synonyms for these words: dominion replenish subdue judgment stewardship find each of the passages using these words related to principles of ecology. list all passages by quote, book, chapter, and verse under each word. use your own interpretation to rewrite what you think each verse is saying. after your discussion of each of these words, ask one other person to explain his understanding of the word and a related verse without any hints. summarize what he tells you. a concluding paragraph for each of the words should be written noting similarities and differences between your interpretation and that of each person consulted.

First described the system of fingerprint ridges and spirals, which eventually were used for fingerprinting. a.) fare and fidelis’s pathology b.) dr. calvin goddard c.) hans gross d.) marcelo malpighi e.) leeuvenhoek’s microscope