  Is there a functional role for quantum mechanics or coherent quantum effects
in biological processes? While this question is as old as quantum theory, only
recently have measurements on biological systems on ultra-fast time-scales shed
light on a possible answer. In this review we give an overview of the two main
candidates for biological systems which may harness such functional quantum
effects: photosynthesis and magnetoreception. We discuss some of the latest
evidence both for and against room temperature quantum coherence, and consider
whether there is truly a functional role for coherence in these biological
mechanisms. Finally, we give a brief overview of some more speculative examples
of functional quantum biology including the sense of smell, long-range quantum
tunneling in proteins, biological photoreceptors, and the flow of ions across a
cell membrane.
