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A typical operon. In genetics, an operon is a functioning unit of DNA containing a cluster of genes under the control of a single promoter. [1] The genes are transcribed together into an mRNA strand and either translated together in the cytoplasm, or undergo splicing to create monocistronic mRNAs that are translated separately, i.e. several strands of mRNA that each encode a single gene product.
Attenuators may be classified according to the type of molecule which induces the change in RNA structure. It is likely that transcription-attenuation mechanisms developed early, perhaps prior to the archaea/bacteria separation and have since evolved to use a number of different sensing molecules (the tryptophan biosynthetic operon has been found to use three different mechanisms in different ...
There are 52 genes that encode the ribosomal proteins, and they can be found in 20 operons within prokaryotic DNA. Regulation of ribosome synthesis hinges on the regulation of the rRNA itself. First, a reduction in aminoacyl-tRNA will cause the prokaryotic cell to respond by lowering transcription and translation. This occurs through a series ...
DNA synthesis occurs in all eukaryotes and prokaryotes, as well as some viruses. The accurate synthesis of DNA is important in order to avoid mutations to DNA. In humans, mutations could lead to diseases such as cancer so DNA synthesis, and the machinery involved in vivo, has been studied extensively throughout the decades. In the future these ...
An active enhancer regulatory sequence of DNA is enabled to interact with the promoter DNA regulatory sequence of its target gene by formation of a chromosome loop. This can initiate messenger RNA (mRNA) synthesis by RNA polymerase II (RNAP II) bound to the promoter at the transcription start site of the gene. The loop is stabilized by one ...
Selenium plays important roles in hormone function, a healthy metabolism, DNA synthesis and protection from oxidative damage and infection, notes the U.S. National Institutes of Health ...
Structure of the trp operon. The trp operon is a group of genes that are transcribed together, encoding the enzymes that produce the amino acid tryptophan in bacteria. The trp operon was first characterized in Escherichia coli, and it has since been discovered in many other bacteria. [1]
Many Americans are counting on their tax refunds to help make ends meet. Here's when you can expect yours.