(a) Porins-Types of proteins which forms pores of large size in the outer membranes of plastids such as chloroplast, mitochondria and membranes in bacteria. (b) Leg-Haemoglobin-Pink pigment in root nodules of leguminous plants, as soybean, that is essential for N2− fixation. It acts as O2-scavenger (c) H+-accumulation → lumen of thylakoid. (d) Respiration-Amphibolic pathway → a biochemical pathway that includes both anabolic and catabolic processes.