The periplasmic space is the space seen between the plasma membrane and the outer membrane in the gram-negative bacteria. A smaller periplasmic space between the plasma membrane and the peptidoglycan layer (cell wall) may be observed in the gram-positive bacteria. Periplasmic space may be filled with a loose network of peptidoglycan and may constitute up to 40% of the total cell volume. This space is involved in various biochemical pathways including nutrient acquisition, synthesis of peptidoglycan, electron transport, and alteration of substances toxic to the cell. Gram-positive bacteria do not have as many periplasmic proteins compared to the gram-negative bacteria. Instead gram-positive bacteria secrete enzymes which would normally be found in the periplasmic space of the gram-negative bacteria. These secreted enzymes are referred to as exoenzymes. Substance that occupies the periplasmic space is reffered to as a periplasm. Drawing of a cell membrane A component of every biological cell, the cell membrane (or plasma membrane) is a thin and structured bilayer of phospholipid and protein molecules that envelopes the cell. ... Bacteria that are Gram-negative are not stained dark blue or violet by Gram staining, in contrast to Gram-positive bacteria. ... Phyla/Divisions Actinobacteria Aquificae Bacteroidetes/Chlorobi Chlamydiae/Verrucomicrobia Chloroflexi Chrysiogenetes Cyanobacteria Deferribacteres Deinococcus_Thermus Dictyoglomi Fibrobacteres/Acidobacteria Firmicutes Fusobacteria Gemmatimonadetes Nitrospirae Omnibacteria Planctomycetes Proteobacteria Spirochaetes Thermodesulfobacteria Thermomicrobia Thermotogae Bacteria (singular, bacterium) are a major group of living organisms. ... Drawing of a cell membrane A component of every biological cell, the cell membrane (or plasma membrane) is a thin and structured bilayer of phospholipid and protein molecules that envelopes the cell. ... Peptidoglycan, also known as murein, is a homogenous layer lying outside the plasma membrane in prokaryotes. ... A cell wall is a more or less solid layer surrounding a cell. ... Gram-positive bacteria are those that are stained dark blue or violet by gram staining, in contrast to gram-negative bacteria, which are not affected by the stain. ... The electron transfer chain (also called the electron transport chain, or simply electron transport), is a series of protein complexers and lipid messengers spanning the inner mitochondrial membrane that accepts electrons from electron donors such as NADH or succinate, shuttles these electrons from within the mitochondrial matrix across the inner... A representation of the 3D structure of myoglobin, showing coloured alpha helices. ... Neuraminidase ribbon diagram An enzyme (in Greek en = in and zyme = blend) is a protein, or protein complex, that catalyzes a chemical reaction and also controls the 3D orientation of the catalyzed substrates. ... The periplasmic space is the space seen between the plasma membrane and the outer membrane in the gram-negative bacteria. ... The periplasmic space is the space seen between the plasma membrane and the outer membrane in the gram-negative bacteria. ...