Please memorize the chemical structures of the underlined chemicals below:
methyl alcohol, ethyl alcohol, propyl alcohol
formaldehyde, acetaldehyde, acetone
formic acid, acetic acid, propionic acid
(butyric acid, stearic acid etc.) fatty acids
Predicting solubilities in water? or in oil? ("lipids")
1) Bigger molecules are more liquid or solid (other things being equal)
2) Alcohol, acid and amino groups bond to each other, thereby making molecules behave as if bigger. (bigger=heavier)
3) "Like dissolves like" (dissolve in water if bonding groups)
(when NO such groups, the chemical may dissolve in oils, & NOT water)
The concept of isomers (as in the cases of propyl alcohol and acetone)
amino acids
How are "alpha amino acids" different from, say, beta amino acids? (can the alphas beat the betas in a fight, or something like that?) (hint: no)
glycine, alanine, serine,
(aspartic acid..lysine)
Proteins are chains of 20 different kinds of alpha amino acids
Questions for chapter two: (These are the kinds of questions to expect on the exams.)
* Stars mean that question is rather difficult; so don't panic if you don't know the answer right away. Exams would not have too many questions difficult enough to earn stars.
** Two or more stars mean that the question is very difficult; exams would have very few questions of this level of difficulty.
*** Three or 4 stars mean the instructor may not even be able to figure it out, and will be very favorably impressed if you bring him the answer.
1) Formaldehyde is to methane as what is to propane? (structurally)
*2) Acetic acid is to what
as ethane is to gasoline, kerosene, & fuel oils?
3) What chemical would you get if you added a methyl group to the alpha carbon of glycine?
4) What chemical would you get if you added a hydroxy to a certain part of alanine? (where could you add a hydroxy to an alanine?)
* 5) Guess the structure of beta alanine!
Contrast this with alpha alanine
(the structure that you learned!)
6) What would you guess is the one amino acid that cannot have a beta isomer? (hint: it's easy!)
*7) Figure out how many different isomers there are of butyl alcohol.
**Pentyl alcohol
(*** figure out the general equation for numbers of isomers, if "n" is the number of carbons)
8) What are the patterns of differences in
**second: comparing ethane to ethyl alcohol to acetic acid, etc. (I admit that formaldehyde is a gas)
9) Imagine molecules in which one end would dissolve in water, but the other end would NOT! Sketch!
*10) Would you expect it to be possible to have a 3-carbon compound, with OHs on all carbons?
* Why would this chemical be gooey? and taste sweet?
(please don't go around tasting chemicals, however!)