Molecular beacons consist of a stem (5–7 bp), and a loop (18–30 base pairs) and are labeled at the 5′ and 3′ ends by fluorophores and quenchers, respectively. 

TLS Online TPP Program

#Id: 645

#Unit 3. Fundamental Processes

hydroxylating agent hydroxylamine (NH2OH) induces only G:C → A:T transitions not reversal.

TLS Online TPP Program

#Id: 646

#Unit 3. Fundamental Processes

When DNA is treated with hydroxylamine, the amino group of cytosine is hydroxylated.

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.