The proposed work falls into fve parts, two dealing with the regulation of chloroplast membrane and chloroplast-soluble protein syntheses in synchronous cultures of Chlamydomonas reinhardtii, two dealing with the isolation of differentiated areas of the membrane system in central nervous system neurons, and one with the characterization of an enzyme, cytochrome P450, in the endoplasmic reticulum membranes. The five test systems are: (a) the possible differential appearance of thylakoid membrane proteins during the light period of synchronous C. reinhardtii cells, when the cells and chloroplasts increase in mass some 4- to 6-fold, and the effect of dark-interruption periods on these syntheses; (b) the regulation of the synthesis of a soluble chloroplast enzyme, ribulose diphosphate carboxylase, during the same cell cycle, particularly the synchrony of the synthesis within the chloroplast of the large subunit of this enzyme with the synthesis outside the chloroplast of the small subunit of this enzyme, and how they come together to form the complete chloroplast enzyme; (c) the isolation, purification, and determination of biochemical properties from the central nervous system of the two differentiated areas of the plasma membranes which are involved in nerve impulse conduction, the synaptic junction complex (pre- and post-synaptc membranes) and the electrotonic (gap) juncttons; (d) the purification of the black widow spider venom and studies on its mode of action on the presynaptic membranes of nicotinic and adrenergic pathways; and (e) the verification of the possible subunit status of the approximately 50,000 MW insoluble ER membrane protein, cytochrome P450.