How do the senses of smell and taste function?

75% of taste is contributed by smell. "Think about when you've a cold. You've got this stuffed up nose. I mean, what did things taste like? Not so great," says Karen Kalumuck a biologist at San Francisco's Exploratorium, "That's really because we can't have the odorant molecules meet up with the sensory receptors in the nose and transmit that information to the brain."