Alkylating agents, Deaminating chemicals, Hydroxylamine, intercalating agents.
Classes of radiation-inducing mutagens include: Ionizing radiation (X-rays and gamma rays), Non-ionizing radiation (ultraviolet light). Regardless of how DNA mutation arises, it is important for cells to prevent an incorporated error from leading to replicated error. An incorporated error is one where damaged, incorrect, or mismatched bases are introduced into the DNA molecule, while replicated error is one where the incorporated error was used as a template for DNA replication, thereby making this mutation permanent. Fortunately, if a mutation occurs, cells have several DNA repair mechanisms that are able to detect and correct many types of DNA damage before they become permanent. For each of the following descriptions, select the correct type of DNA repair mechanism involved to correct these mutations: (Use the drop-down menus to make your selections and please only use each option only once):
(a) Bulky lesions that distort the DNA double helix are removed by cutting out a large section of the DNA that surrounds the damage and then re-synthesizing this section of DNA. (1 mark)
(b) If an incorrect nucleotide was incorporated during DNA replication, the enzymes in this mechanism excise the incorrectly paired nucleotide from the newly synthesized strand then use the original nucleotide strand as a template to insert the correct nucleotide. (1 mark)
(c) The modified base is first removed, followed by the replacement of the entire nucleotide at that position with the correct one. (1 mark)
(d) The modified bases are chemically changed back into their original structures without breaking the DNA backbone. (1 mark)