In the figure at right, you see that molecules with a hydrogen bond donor (an OH group in a sugar) about 3 x 10-8 cm away from a hydrogen bond acceptor (another OH group in the sugar) are able to strongly interact with the sugar receptor protein in the taste bud. It is also important that there is a relatively non-polar part between the hydrogen bond donor and acceptor. In sugars, the non-polar part consists of the C-H bonds adjacent to the OH groups.