K+ leak channels are found in the plasma membrane. These channels open and close in an unregulated, random fashion. What do they accomplish in a resting cell?
Answer:
They set the K+ concentration gradient to zero.
They set the membrane potential to zero.
They disrupt the resting membrane potential.
They keep the electrochemical gradient for K+ at zero. 

Water molecules readily form hydrogen bonds with other polar molecules, and when they encounter nonpolar molecules they must form hydrogen-bonding networks with neighboring water molecules. Which of the following molecules will cause a "cage" of water to form?
Answer:
2-methylpropane
acetone
methanol
urea