BIO153H5 Chapter Notes - Chapter 27, 30: Gametophyte, Pollen Tube, Gymnosperm
Document Summary
Prokaryotic species are able to adapt to a broad range of habitats, which helps explain why they are the most abundant organisms on earth. In most bacterial cell walls: gram stain: technique used to classify bacterial species into two groups based on cell wall composition. Valuable in determining whether infection is caused by gram +ve or ve bacteria. Gram positive: simpler walls with large amount of peptidoglycan. Some virulent species resistant to one or more antibiotics. Gram negative: less peptidoglycan and more structurally complex outer membrane contains lipopolysaccharides, which are often toxic. Outer membrane helps protect against body"s defenses, and is more resistant to antibiotics than gram +ve species. Effectiveness of certain antibiotics derives from inhibiting peptidoglycan cross-linking. Capsule (if dense and well defined) or slime layer (if opposing): Sticky layer of polysaccharide or protein surrounding some prokaryotes allowing them to adhere to substrate or other individuals in a colony.
