When Bacteria Attack Exotoxins Poisons released to weaken host Clostridium botulinum Clostridium tetani Vibrio cholerae
When Bacteria Attack Endotoxins Poisons located in outer membrane Escherichia coli, Salmonella
Review Questions 1.Bacteria cannot grow in temperatures above 100 o C, so why is pressure cooking at 120 o C and 15-20psi necessary for sterilization? 2. Contrast chemoautotrophism and chemoheterotrophism. 3. Carbon fixation : mesophyll cells : nitrogen fixation :: _________ 4. Would you rather be infected by a Gram + or a Gram - bacterium?
Review Answers 1. Some Gram+ bacteria can form endospores and resist boiling. The combination of heat and high pressure can kill them, though. 2. Chemoautotrophism – Chemical energy source and CO 2 carbon source. Chemoheterotrophism – Chemical energy source and organic carbon source. 3. Carbon fixation : mesophyll cells : nitrogen fixation :: heterocysts 4. Gram+ because they are more likely to be susceptible to antibiotics, and Gram- can contain endotoxins. OR Gram- because some Gram+ can form endospores.