At pH7, charged or polar molecules will charge or polarize. Based on what properties could I predict its behavior? For ex., lysine will be charged because NH2 will pick up a H+. Will glutamine be charged? The NH2 group and the O will not pick up any H+? How can I predict if either group will pick up a H+ or not?
You just have to memorize the properties of the functional groups as to their acidity or basicity: R-COOH groups are the only organic groups that we talk about that lose a proton and so become negatively charged, and amines take on a proton and become postively charged. Amines include R-NH2 and the guanido group of arginine, R--NH-CNH-NH2, but NOT the -NH2 of amides, R-CO-NH2. Thus glutamine, asparagne, and the peptide bonds in polypeptides do NOT gain a full charge. You can figure out polarity if you remember that O and N are more electronegative than H or C, so those combinations will result in partial charge separations and polarity.