Well both languages are used fairly extensively for derivation of taxonomy designations of species, families, orders etc. An awful lot of greek in chemistry too, especially biology, in chemistry not so many but biology in particular and particle physics you need a pretty good knowledge of the greek alphabet. There are bits and pieces labeled not just from alpha to omega, so to speak, but right 'through' to zeta (thinking in particular of the zeta opioid receptor, although it doesn't bind opioids IIRC, possibly opioid neuropeptides, but its more based on a loose sequence homology similarity, and that at maybe 40-50% which is as slack as jenny McWhorethy's tartarus chasm. Its more of a growth factor receptor involved in regulation of cell proliferation, and has fuck all to do with painkillers, or delta/kappa opioid receptors, or nociceptin receptors.