You will only be able to see the first 20 seconds. We recommend downloading the newest version of Flash here, but we support all versions 10 and above. If that doesn't help, please let us know. Unable to load video. Please check your Internet connection and reload this page. If the problem continues, please let us know and we'll try to help. An unexpected error occurred. Previous Video Each one plays a different role in the synthesis of proteins.
The codons, groups of three nucleotides, in an mRNA molecule, direct the production of a protein by specifying the amino acid sequence and indicating where protein synthesis should start and stop. Here, a tRNA molecule, with a three-nucleotide anticodon sequence on one side and a specific amino acid on the other, binds to a complementary codon in the mRNA. The amino acids from the tRNAs bind to each other, creating a polypeptide with a sequence of amino acids specified by the mRNA.
Non-coding RNAs play important roles in the regulation of gene expression in response to developmental and environmental changes. Non-coding RNAs in prokaryotes can be manipulated to develop more effective antibacterial drugs for human or animal use.
The central dogma of molecular biology states that DNA contains the information that encodes proteins, and RNA uses this information to direct protein synthesis. It consists of codons—sequences of three nucleotides that encode a specific amino acid.
During translation, ribosomes move along an mRNA strand where they stabilize the binding of tRNA molecules and catalyze the formation of peptide bonds between amino acids. Thus, different types of RNA perform specific but complementary functions during protein synthesis. However, their roles in regulating gene expression were discovered over the past few decades and continue to be extensively researched.
Both small regulatory RNAs and long non-coding RNAs regulate gene expression by altering various stages of transcription and translation. In this manner, they control the formation of different protein variants from a single gene.
Long non-coding RNAs interact with and recruit enzymes that chemically modify DNA and histones — proteins that help package DNA into the nucleus — to either activate or repress transcription. RNA-mediated regulation of gene expression is widespread in bacteria. Regulatory sequences in mRNA—called riboswitches—act as environmental sensors by detecting changes in temperature and nutrient levels. Riboswitch-based regulation depends on the formation of two mutually exclusive and stable conformations of the RNA secondary structure.
The secondary structure switches between the two conformations to turn gene expression on or off in response to environmental changes. This content is taken from Taipei Medical University online course,. This content is taken from Taipei Medical University online course. Share this post. See other articles from this course. This article is from the online course:. Join Now. News categories. Other top stories on FutureLearn.
Category: General. We take a closer look at media literacy and what makes it so important in …. Register for free to receive relevant updates on courses and news from FutureLearn. Create an account to receive our newsletter, course recommendations and promotions. RNA is then translated into proteins by structures called ribosomes. Related Concepts You have authorized LearnCasting of your reading list in Scitable.
She has taught science courses at the high school, college, and graduate levels. Facebook Facebook Twitter Twitter. Updated September 12, Featured Video. Cite this Article Format. Helmenstine, Anne Marie, Ph. Ribosomes - The Protein Builders of a Cell.
What Is a Peptide? Definition and Examples.
0コメント