Question: If a lipid bilayer does not form in a test tube of phospholipids in a liquid solvent and instead the heads join together in a circular pattern, the most likely explantion is:

a)  The solvent is polar like water.

b)  The solvent could be an oil.

c)  the fatty acid tails must have trans double bonds.

d)  The phospholipid heads have no charged functional groups.

Question: Assume many of the atoms of nitrogen in a double-stranded molecule of DNA, of isotope N-14, were replaced with the isotope N-15. Determine what afffect would this have?

a)  The nitrogeneous bases would become slightly basic.

b)  the Base pairing would no longer occur naturally,

c)  The DNA could turn into RNA

d)  there would be no detectable effect on the DNA

f)  The molecule would increase in mass slightly.