Mutagens and DNA

A mutagen refers to any agent found in an organism's environment capable of producing genetic mutations in DNA.

Some DNA repair mechanisms include base excision repair (BER), nucleotide excision repair (NER), and mismatch repair (MMR).

Base excision repair occurs during the G1 stage of the normal cell cycle.

<p>Nucleotide excision repair occurs during the G1 and G2 stages of the cell cycle.</p> Signup and view all the answers

<p>The purpose of mismatch repair is to ensure that base pair matching is maintained within the DNA.</p> Signup and view all the answers

<p>The term mutagenic is defined as the ability to induce genetic changes in the DNA of an organism.</p> Signup and view all the answers

<p>Some sources of mutagenic agents include physical, chemical, and biological mechanisms.</p> Signup and view all the answers

<p>Some examples of physical mutagens include UV or gamma radiation.</p> Signup and view all the answers

<p>Some examples of chemical mutagens include alkylating agents and azides.</p> Signup and view all the answers

<p>Some examples of biological mutagens include viruses and different bacterial species.</p> Signup and view all the answers

<p>Free radicals are molecules with unpaired electrons. They form when sources induce the creation of unpaired electrons in molecules.</p> Signup and view all the answers

<p>Thymine dimers prevent the formation of the double helix by creating unintentional bonds between bases, such as covalent bonds between thymine molecules.</p> Signup and view all the answers

<p>Xeroderma pigmentosum is a condition that increases the risk of skin cancer due to extreme light sensitivity. It is caused by the lack of an enzyme needed to remove thymine dimers from DNA sequences.</p> Signup and view all the answers

<p>Chemical mutagens are compounds that produce toxicity and damage DNA. They directly impact bases by creating mismatches between base pairs and inducing DNA repair mechanisms.</p> Signup and view all the answers

<p>Nitrous acid is an example of a chemical mutagen. It causes base switching, converting cytosine to uracil, adenine to hypoxanthine, and guanine to xanthine.</p> Signup and view all the answers

<p>Biological mutagens consist of bacteria and viruses capable of producing mutations in DNA. They cause mutations by infecting cells and interfering with DNA replication and repair processes.</p> Signup and view all the answers

<p>Human papillomavirus (HPV) is an example of a biological mutagen. It can result in long-term infection and the development of precancerous cells in the reproductive tract.</p> Signup and view all the answers

<p>Alkylation is the addition of alkyl groups to bases, leading to increases in DNA mutations.</p> Signup and view all the answers

<p>Oxidation is the production of free radicals causing lesion formation in DNA.</p> Signup and view all the answers

<p>Mutations introduce new traits into a population. When these mutations enhance fitness and the ability to pass on beneficial traits, natural selection acts upon them, facilitating the process of evolution.</p> Signup and view all the answers