The toxicity of {HEAD ~ these molecules} is based upon {TAIL ~ their relative affinity} for the receptor which far exceeds that of acetylcholine 
The toxicity of { HEAD ~ these molecules } is based upon { TAIL ~ their relative affinity } for the receptor which far exceeds that of acetylcholine
OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH