Aldoses Ketoses Aldoses and ketoses are tautomeric forms,i.e.they are isomeric compounds differing only in the positon of a proton and the concomittant exchange of a chemical bond. c=0 H H H一 一OH H一C一OH C=0 H一C一OH H一C一OH H一C一OH H一C一OH H,C-OH H2C-OH D-Ribose D-RibuloseAldoses - Ketoses Aldoses and ketoses are tautomeric forms, i.e. they are isomeric compounds differing only in the positon of a proton and the concomittant exchange of a chemical bond. C C C C C O OH OH OH OH H H H H H2 C C C C C OH O OH OH OH H H H H H2 D - Ribose D - Ribulose