BIOL 115 Lecture Notes - Lecture 24: Gram Staining, Pilus, Transfer Dna
Document Summary
Microbes microscopic organisms, such as bacteria, viruses, and protists. Widely distributed in the environment, on inanimate objects and living things. Bacteria contribute to the production of yogurt, cheese, bread, beer, wine, and many pickled foods. Without the activity of decomposers, the biosphere wouldn"t exist. Barriers to prevent pathogens from entering the body (skin, mucous membranes) Phagocytic wbcs fight infection after a pathogen gets past the barriers and into the body. Acquired defenses kill pathogens and protect against cancer. Three common shapes: coccus (sphere-shaped), bacillus (rod-shaped), and spirillum (curved, sometimes spiral-shaped) Most have a cell wall in addition to the plasma membrane. Cell wall contains peptidoglycan (a disaccharide with an amino group) Some antibiotics, such as penicillin, interfere with the production of the cell wall. Some are surrounded by a capsule that allows bacteria to stick to surfaces and protects them. Bacteria are classified by differences in their cell walls, which are detected using gram stain.
