PNPase a 3’ to 5’ exonucleases in E. coli, are unable to progress through double-stranded regions. Thus, the stem-loop structure at the 3’ end of many bacterial mRNAs protects the mRNA from direct 3’ attack.

TLS Online TPP Program

#Id: 642

#Unit 3. Fundamental Processes

Alkylating agents are chemicals that donate alkyl groups to other molecules as nitrogen mustard, and methyl and ethyl methane sulfonate (MMS and EMS).

TLS Online TPP Program

#Id: 643

#Unit 3. Fundamental Processes

EMS causes ethylation of the bases in DNA at the 7-N and the 6-O positions of G cause G:C → A:T transitions.

TLS Online TPP Program

#Id: 644

#Unit 3. Fundamental Processes

Alkylating agents induce all types of mutations, including transitions, transversions, frameshifts, and even chromosome aberrations.

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.