MCB 3020 Lecture Notes - Lecture 5: Nucleoid, Peptidoglycan, Germination
Document Summary
Chapter 3: bacterial cell structure: bacteria and archaea have directed movement, chemotaxis. Move toward chemical attractants such as nutrients, away from harmful substances: move in response to temperature, light, oxygen, osmotic pressure, and gravity. Chemotaxis: movement toward a chemical attractant or away from a chemical repellent, changing concentrations of chemical attractants and chemical repellents bind chemoreceptors of chemosensing system. Bacterial endospore: complex, dormant structure formed by some bacteria, various locations within the cell, resistant to numerous environmental conditions. Endospore structure: spore surrounded by thin covering called exosporium, thick layers of protein form the spore coat, cortex, beneath the coat, thick peptidoglycan, core has nucleoid and ribosomes. What makes an endospore so resistant: calcium (complexed with dipicolinic acid, small, acid-soluble, dna-binding proteins (sasps, dehydrated core, spore coat and exosporium protect. Sporulation: process of endospore formation, occurs in a hours (up to 10 hours, normally commences when growth ceases because of lack of nutrients, complex multistage process.
