There are three amino acids that have basic side chains at neutral pH. These are arginine (Arg), lysine (Lys), and histidine (His). Their side chains contain nitrogen and resemble ammonia, which is a base. Their pKa's are high enough that they tend to bind protons, gaining a positive charge in the process.
Similarly one may ask, is serine charged?
The charged amino acid residues include lysine (+), arginine (+), aspartate (-) and glutamate (-). Polar amino acids include serine, threonine, asparagine, glutamine, histidine and tyrosine.
Are positively charged amino acids hydrophilic?
* Some amino acid side chains are positively charged; some are negatively charged; some are neutral; some are hydrophobic; some are hydrophilic. They dissolve in the water. Hydrophilic molecules are polar, and can join the Hydrogen Bond network that polar water molecules form.