The mechanism of phase variation in Salmonella typhimurium:
A. uses site-specific recombination to invert the fljA and fljB genes so they now are not contiguous with their promoter. Expression of these genes is now prevented.
B. uses site-specific recombination to invert the fljA and fljB promoter, preventing transcription of the two genes. Without repressor the fljC protein is now expressed.
C. uses site-specific recombination to delete the repressor, fljA. Without repressor the fljC protein is now expressed.
D. uses site-specific recombination to delete the fljB gene so only fljC can be expressed.
E. None of the choices given is true.
B
You might also like to view...
Campylobacter infections are the MOST common foodborne infections in the United States
Indicate whether the statement is true or false.
What is the method called that indicates the
age of material by measuring the content of the radioisotope and the daughter elements?
a. radiometric dating b. carbon dating c. catastrophism d. all of these e. none of these
Ecology and environmentalism are the same scientific discipline
Indicate whether the statement is true or false
One function of the developing follicle is to:
a. stimulate ovulation. b. secrete progesterone. c. secrete estrogens. d. secrete prolactin. e. secrete glycoproteins, which promote sperm motility.