Are basic R-groups of an amino acid positively or negatively charged

In an aqueous medium?

Say The groups NH4+ and R OH +2 , they are known as the conjugate acids and they are positively-charged.

So should basic R-groups be considered positively-or negatively-charged.

My notes say basic R-groups are positively-charged, but I thought negative is correct.

Please help me!

Thanks a lot!

In an unionized form, the side chain of lysine is R-NH2. But this acts as a base, and at a pH of 7, the side chain nitrogen gains a proton and exists as R-NH3+

So, the amino acid is basic, but at neutral pH, exists as a positively charged ion.

Likewise, the acidic amino acids like Glu and Asp, contain a carboxyl. At neutral pH, they have transferred their proton to water, and so exist as R-COO-

The acidic amino acids at neutral pH have negatively-charged side chains, and the basic amino acids at neutral pH have positively-charged side chains.

Hope this helps out...