Question

Give some example of endogeneously dna damaging agent

Answer 1

Each human diploid cell contains in the pre‐replicating state 6 × 109 base pairs in the DNA, which corresponds to a total amount of 12 × 1022 nucleotides in the human body (given that the body consists of 1013 cells). This huge amount of DNA, packed into 46 chromosomes (diploid), is under constant attack by endogenous and exogenous reactive molecules that causes damage in DNA bases or its sugar phosphate backbone. Furthermore, some DNA damaging agents (DDA) may cause the formation of covalent bonds between DNA and proteins (DNA protein cross‐links) thus affecting DNA‐histone and DNA‐transcription factor interactions. This has impact on DNA packing (in the case of histones), cell division, replication and transcription of DNA.

Characteristics

Most of the DNA lesions that are formed spontaneously or by the attack of endogenous and exogenous reactive molecules are repaired, i.e. removed in an error‐free manner (for review see ref. 1). Some of the lesions, although they block...