Microorganisms, living within biofilms typically use molecular signals to communicate with each to regulate density-dependent growth; this is commonly referred to as _____ a. horizontal gene transfer. b. quorum sensing. c. cytokine sensing. d. transduction gene transfer. Which of the following represents the best definition for microbial death? a. The organism no longer retains its original shape and structures. b. The organism will not grow on minimal medium. c. The organism will not grow on a medium that normally supports its growth. d. None of these adequately describe microbial death. The destruction or removal of all viable organisms is called _____ a. Sanitization b. antisepsis. c. disinfection. d. sterilization. The time required to kill 90% of the microorganisms or spores in a sample at a specified temperature is the _____ a. thermal death time (TDT) b. z value. c. decimal reduction time (D value). d. thermal death point (TDP). Moist heat sterilization at 100 degree C kills all the following EXCEPT a. viruses. b. bacterial endospores. c. fungal spores. d. Protists Who is usually credited with the discovery of penicillin? a. Fleming b. Duchesne c. Ehrlich d. Florey and Chain Which of the following does not inhibit protein synthesis? a. Erythromycin b. Streptomycin c. Penicillin d. Tetracycline e. All of the choices inhibit protein synthesis.