cephalosporins are 'related' in the sense they both contain the beta lactam ring, and have the same antibacterial mode of action (inhibiting synthesis of the cell wall). although cephaosporins come...
They both are made only of Carbon, Hydrogen and Oxygen. Starch has more of each, regular sugars have less (but all in a 1:2:1 ratio - ie: glucose is C6 H12 O6, "starch" can be C20 H40 O20).