You have discovered an E. coli mutant that expresses a lac operon cap protein that is unable to bind cAMP. If you grew that mutant in glucose, lactose, IPTG, and glucose and lactose how would the galactosidase activity differ from an E. coli strain containing a functional lac operon? What […]

Assume you infected an E. coli culture with a virulent bacteriophage. Most of the cells lysed, but a few survived – 1×10^-4. You wonder where the resistant bacteria came from. Were they caused by the bacteriophage infection or did they already exist in the bacterial culture? Earlier, for a different […]

Viruses are typically not classified as true living organisms by biologists. Viruses have DNA or RNA and protein but are not able to replicate until they infect a host cell. Within the cell they must use the enzymes and molecular building blocks the host cell provides to replicate. Viruses cause […]

1. Aseptic technique refers to        The microbial inoculum placed into a test tube or onto a petridish.        The prevention of contamination.        The isolation of on species of bacteria from a mixedcommunity.        The autoclave or sterilizing procedures.        Cleanliness in the laboratory. 2. This method can be used to sterilize a liquid […]