You've probably heard Depak Chopra and other new-age quacks talk about 'quantum healing' and other similarly pseudo-scientific sounding phrases, so you might be feeling skeptical when you hear the words 'quantum hanky panky' and you see the picture of the pretty girl on the right of this entry, but this ain't Depak Chopra... this is Seth Lloyd, an MIT engineering professor who specializes in quantum mechanics (and especially quantum computing).
In the following presentation, and through the use of some fascinating examples (like photosynthesis, smelling and the avian navigational compass), this endearing geek extraordinaire (with a hilarious laugh, by the way) argues that there is growing evidence that biological systems engage in some ridiculously interesting quantum behavior. Biology, meet quantum mechanics... and make some babies!
In terms of the example about smell, sure, the lock-and-key mechanism may not fully explain what's going on, but why go to the quantum level when the differences in weight between the similarly structured molecules might do the job? Or has that hypothesis been eliminated already?