Catalytic properties of aluminosilicates may play a role in the synthesis of biological molecules from simple gaseous molecules commonly found in planetary atmospheres. Urea, amino acids and UV absorbing substances have been obtained by heating CO and NH3 with Linde molecular sieves saturated with Ca+2, NH4+ or Fe+3. The yields of amino acids produced have been determined by an amino acid analyzer. The quantity of urea produced largely depends on the nature of the saturating cation. Experiments using 14CO confirm that the amino acids are not due to contaminants adsorbed on the surface of the molecular sieves.