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TRANSLATION. RNA PROCESSING. What is RNA processing ? Some nucleotides in DNA DO NOT carry instructions or codes form making protein What are long non-coding nucleotide sequences called? Introns Introns are scattered among the coding sequences
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RNA PROCESSING • What is RNA processing? • Some nucleotides in DNA DO NOT carry instructions or codes form making protein • What are long non-coding nucleotide sequences called? • Introns • Intronsare scattered among the coding sequences • What are regions that DO contain information or codes are called? • Exons(they are expressed) • BothINTRONS& EXONSare copied when mRNA is transcribed from DNA • Introns must be removed from mRNAbefore it can make a protein (mRNA cut into sections & mRNA leaves the nucleus)
THE GENETIC CODE • What is the process of enzymes making RNA copy of a portion of DNA called? • Transcription • What makes up RNA & DNA? • Nucleotides • What’s the alphabet for the language of proteins? • Amino acids • The genetic messages that mRNA gets from DNA are written in a language that uses nitrogen bases as the alphabet • nucleotides are arranged in a specific sequence • these genetic codes convert nitrogen bases into proteins • What is the term used to describe a group of three nitrogenous bases in mRNA • CODON
THE GENETIC CODE • When sequence of 3 bases is used then there is a possibility of 64 codon combinations • SOME codonsprovide instructions for making protein • UAA– STOPcodonindicates the protein chain ends • AUG– STARTcodon& the codon for the amino acid methionine • More than one codon can code for the same amino acid • All organisms use the SAME GENETIC CODE - UNIVERSAL • This is the evidence used to prove that all life on Earth evolved from a common origin • What is formed through translation? • Protein • Many diverse proteins are produced with only 4 nucleotides • 10101010000010101 • Complex proteins are built from the long chains of DNA
TRANSLATION • The process of converting the information in a sequence of nitrogenous bases in mRNA into a sequence of amino acids in protein • Where does translation take place? • The ribosomes in the cytoplasm • mRNA made in the nucleus & travel to the cytoplasm • Ribosomes attach to mRNA (clips) • What’s the role of tRNA? • Each tRNA attaches to only one amino acid • tRNA composed of ~ 80 nucleotides • 3 nitrogen bases located on the side of tRNA molecule • ANTICODON • Anticodonspair up with a mRNAcodon during translatIon • Cytosine anticodonof ACA binds to mRNAcodonUGU
A ribosome attaches to mRNA strand • Molecules of tRNA carries specific amino acids as they approach the ribosomes • Codon, AUG, signals the start of protein synthesis • tRNA carries methionine attaches to the ribosome & mRNA strand • New tRNA carries amino acid attaches to the ribosome • mRNA strand next to previous tRNA • Amino acids on the tRNA join by peptide bond • After peptide bond is formed, ribosomes slide along the mRMNA to the next codon • tRNA no longer carry an amino acid is released • New tRNA carrying amino acid can attach to the ribosome & mRNA strand • A chain of amino acids is formed until a stop codon is reached on the mRNA strand