The Protist Kingdom consists of mostly unicellular organisms that can have characteristics similar to plants, animals or fungi. Characteristics of Protists: mostly unicellular, few multicellular, eukaryotic, can be heterotrophic or autotrophic.Ex: algae, Paramecium, kelp (multicellular). î î î.he Protist Kingdom consists of mostly unicellular organisms that can have characteristics similar to plants, animals or fungi. Characteristics of Protists: mostly unicellular, few multicellular, eukaryotic, can be heterotrophic or autotrophic. Ex: algae, Paramecium, kelp (multicellular). î î î.
The active metabolites of codeine, notably morphine, exert their effects by binding to and activating the Î¼-opioid receptor. This occurs because opioids structurally mimic endogenous endorphins which are naturally found within the body and also work upon the Î¼-opioid receptor set.
Codeine is not itself centrally active, and must first be converted via first pass metabolism into morphine by the cytochrome P450 enzyme CYP2D6 (as such, it is a prodrug for morphine). Codeine is also metabolised into the inactive norcodeine via the CYP3A4 enzyme system.