lectures 7 and 8 - Lectures 7 and 8 Vocab...

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Lectures 7 and 8 Vocab Peptidoglycan-(murein) Polysaccharide composed of alternating repeats of acetylglucosamine and acetylmuramic acid with the later in adjacent layers cross linked by short peptides. Within the periplasmic space. Both gram + and gram - contain it. It is composed of N-acetylglucosamine and N-acetylmuramic acid which link together to form chains(glycan) and certain amino acids form peptid cross linked chains to make sheets. Periplasm- A gel like region between the outer surface of the cytoplasm membrane and the inner surface of the ligopolysaccharid layer of gram negative bacteria. Contains cross linked peptidoglycan supramolecular structure, connected too inner leaflet of the outer membrane by a special (Braun) lipoprotein, will also contain special proteins (certain enzymes and transport proteins.) 20-40% of total cell volume of Gram negative cell. Functions at crossroads of biosynthetic and degradative processes in cell. Contains peptidoglycan matrix (=murein sacculus), a variety of proteins, and some oligosaccharides (for osmotic balance) Lipopolysaccharide- It is in the outer leaflet. The lipid A can be toxic to animals termed endotoxin, can lead to septicemia endotoxic shock. Main components are lipid A- KDO core- O specific polysaccaride( O-antigen). Read notes for function. Membrane leaflet- Murein leaflet- also called murein sacculus. Periplasmic space between out and inner membrane, contains cross linked peptidoglycan supramolecular structure. Peptidoglycan matrix. Braun lipoprotein- a special lipoprotein that connects the out membrane to the peptidoglycan sheet in the periplasm. A very abundant protein that stabilizes the OM- peptidoglycan complex and contributes to formation of periplasm. Lipid A- Part of the structure of the lip polysaccharide. It can be toxic in animals: this component of the LPS is termed endotoxin. Can lead to Septicemic Endotoxic Shock. The lipid A-KDO portion is essential for the formation, stabilization and function of the out membrane, including the growth of the cell. Endotoxin- The portion of the LPS that contains lipid A is toxic and called endotoxin. Hydrophobic- Non polar portion of the cell, repel from water. Project into the interior of the cell wall. (R-group) Hydrophilic- Polar portion of the cell, attracted to water. Form the surface of the cell wall(phosphate ester polar head group.
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Porins- Most are trimetric transmembrane proteins with water filled channels. Allow passive diffusion of small hydrophilic solutes across outer membrane. Most provide non specific transport but some are solute specific. Channels exclude hydrophobic solutes and larger hydrophilic solutes. Porins fit into the space of the 3-point star structure of the
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This note was uploaded on 04/02/2008 for the course PSY 101 taught by Professor Jackson during the Fall '08 term at Michigan State University.

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lectures 7 and 8 - Lectures 7 and 8 Vocab...

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