Help with Protein Synthesis?

PROTEIN SYNTHESIS QUESTION. PLEASE HELP ME!?

• Answer:

  salam, you are talking about transcription and translation Transcription Nucleotides are added to the 3' end of RNA using information in DNA as instructions. Only one strand of DNA is used to synthesize RNA in transcription, the other has redundant information because it is complimentary. In the vast majority of cases there is no overlap between the two strands. However, it is possible to have coding regions in both directions. This is rare and dangerous because a single mutation can knock out two genes at the same time. Translation mRNA contains information needed to synthesize proteins. Protein synthesis begins at a start signal at the 5' end of the mRNA and continues along the coding sequence towards 3' end until it reaches a stop signal. There might be extra information, or untranslated regions at the ends of the mRNA (called flanking sequences) that don't code for protein. The extra sequence at the 5' end is called a leader sequence and the extra sequence at the 3' end is called a trailer sequence. In eukaryotes, the ends contain control elements which contain signals (for example, to degrade or stabalize) which regulate the amount of translation. The mRNA might be thousands of nucleotides long. In eukaryones there are only single coding regions on each RNA strand, but in prokaryotes more than one coding region can be present on the same mRNA. This is called polycistronic mRNA because on a single mRNA there are multiple coding sequences which will produce different proteins. The different coding regions will likely be related in function. Separate initiation and termination signals are needed to translate each coding region. A cistron is the gene in a prokaryotic organism that codes for a specific protein. The main objective of translation is to convert the genetic information in the mRNA into a functional protein. The terms: proteins, peptides and polypeptides are used interchangeably and may be confusing. A protein is made up of one or more polypeptide chain. There are many components functioning in translation. Ribosomes contain about 80 proteins and 3-5 ribosomal RNAs (rRNAs) which interact to form a specific structure. The ribosomes are the "factory" for protein synthesis. They are responsibile for initiation at the correct site, accurate elongation, and termination of protein synthesis. The ribosome reads information along the mRNA, coordinates bringing the amino acids together and guides assembly into proteins. more on it here: http://www.dartmouth.edu/~cbbc/courses/bio4/bio4-lectures/ProteinSynthesis.html