BIOL 201 Lecture Notes - Lecture 10: Open Reading Frame, Non-Coding Rna, Ethidium Bromide
9 Feb 2013
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Document Summary
Many mutagens fit into the space between two adjacent base pairs, this is calledintercalation. Most intercalators are aromatic and planar molecules; examples include ethidium bromide, acridines,daunomycin, and doxorubicin. In order for an intercalator to fit between base pairs, the bases must separate, distorting the dna strands by unwinding of the double helix. This inhibits both transcription and dna replication, causing toxicity and mutations. Dna intercalators may be carcinogens, and in the case of thalidomide, a teratogen. Others such as benzo[a]pyrene diol epoxide and aflatoxin form dna adducts which induce errors in replication. Nevertheless, due to their ability to inhibit dna transcription and replication, other similar toxins are also used in chemotherapy to inhibit rapidly growingcancer cells. Dna usually occurs as linear chromosomes in eukaryotes, and circular chromosomes in prokaryotes. The set of chromosomes in a cell makes up its genome; the human genome has approximately 3 billion base pairs of dna arranged into 46 chromosomes.
