<prompt> Glucose is linked to hemoglobin throughN linkageO linkageC-C linkageO-H linkage  <response>: The glycated hemoglobins are together called HbA1 fraction.Out of this 80 molecules are HbA1c, where glucose is attached to the N -terminal valine of beta chain of hemoglobin. The rest of molecules are HbA1a1, where fructose 1,6-phospate and HbA1a2, where glucose-6-phosphate are attached. REF :DM VASUDEVAN TEXTBBOK ,7th EDITION; Page no :328 