Classify each phrase as a description of alpha helices, beta sheets, beta turns, or all. a Helices successive R groups point in opposite directions Sheets Answer Bank Turns all -NH groups point in the same direction first residue hydrogen-bonded to fifth residue (that is, residue n is H-bonded to residue n+4) first residue hydrogen-bonded to fourth residue (that is, residue n is H-bonded to residue n+3) All contains - NH hydrogen-bonded to C=0