Cholera toxin, secreted by Vibrio cholerae in the intestine of an infected person, is a heterodimeric protein (AB). 

TLS Online TPP Program

#Id: 647

#Unit 3. Fundamental Processes

X rays, gamma rays, and cosmic rays is ionizing radiation and ultraviolet light is nonionizing radiation.

TLS Online TPP Program

#Id: 648

#Unit 3. Fundamental Processes

1 roentgen unit is a quantity of X ray that produces 2.083X109 ion pairs in one cubic centimeter of air at 0C and a pressure of 760 mm of mercury.

TLS Online TPP Program

#Id: 649

#Unit 3. Fundamental Processes

The maximum absorption of UV by DNA is at a wavelength of 254 nm. Maximum mutagenicity also occurs at 254 nm. 

TLS Online TPP Program

#Id: 650

#Unit 3. Fundamental Processes

Two major products of UV absorption by pyrimidines (thymine and cytosine) are pyrimidine hydrates and pyrimidine dimers.

TLS Online TPP Program

#Id: 651

#Unit 3. Fundamental Processes

Ames Test is used to measure carcinogenicity and mutagenicity of any chemical mutagen.

TLS Online TPP Program

#Id: 652

#Unit 3. Fundamental Processes

The Ames test uses a strain of S. typhimurium that is mutant for the operon responsible for the biosynthesis of the amino acid histidine.