MCB 2004C Lecture Notes - Lecture 2: Optical Microscope, Lipid A, Clostridium
Document Summary
Cells are smaller and simpler than eukaryotes: reproduction: binary fission, no membrane bound organelles, major structures. Cytoplasmic membrane: endospores, ~ 8 nm thick, establishes the integrity of the cell. Contains integral membrane proteins: highly ordered yet relatively fluid ( fluid mosaic ) Cell walls of bacteria: gram-negative outer membrane, a second lipid layer. Lipid and polysaccharide linked to form lipopolysaccharides: often called the lipopolysaccharide layer or lps. Lipid a = endotoxin: gram-positive cell wall. Contains teichoic acid as well as lipoteichoic acid: they are species specific, not found in gram-negatives, arrangement of dna, usually a single circular molecule, no nucleus, nucleoid, plasmids: small, circular, extrachromosomal dsdna, bacterial flagella. Long, thin appendages free at one end and attached to the cell at the other end: for movement, ~ 20 nm in diameter, too thin for the light compound microscope. Fimbriae & pili: both structurally similar to flagella but not involved in movement, more prominent in gram-negative.
