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DNA: Transcription & Translation. How do we go from DNA to PROTEIN?. WHAT DO WE NEED?. DNA RNA mRNA: messenger RNA rRNA: ribosomal RNA tRNA: transfer RNA Amino Acids Proteins. DNA. The genetic code or “blue-print” of life Contains the bases A, T, C, and G to code for amino acids.
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DNA: Transcription & Translation How do we go from DNA to PROTEIN?
WHAT DO WE NEED? • DNA • RNA • mRNA: messenger RNA • rRNA: ribosomal RNA • tRNA: transfer RNA • Amino Acids Proteins
DNA • The genetic code or “blue-print” of life • Contains the bases A, T, C, and G to code for amino acids
DNA/ Genes/ Codons • DNA is made of approximately 80,000 genes • Genes are sections of DNA that code for a single protein • Codons are a set of 3 bases that code for an amino acid
RNA • Polymer of ribonucleotides • Sugar (ribose) • Phosphate group • Nitrogenous base (A, U, C, G) • Single-strand • Three types: mRNA, rRNA, tRNA
ROLES OF RNA • mRNA: transports information from DNA from the nucleus to the cell’s cytoplasm • rRNA: (makes up ribosomes): clamps on to mRNA and reads its information to assemble amino acids in the correct order • tRNA: transports amino acids to the ribosomes to be assembled into proteins
TRANSCRIPTION • Process in the cell’s nucleus where enzymes make an RNA copy (mRNA) of the DNA strand
Steps of Transcription • Separation of Strands: enzymes unzip DNA in the bases • Base Pairing: free RNA ribonucleotides pair with complementary DNA bases • Only happens to ONE strand of DNA • Uracil bonds with Adenine of the DNA
Steps of Transcription (cont’d) • Ribonucleotides Bond: ribonucleotides of mRNA bond due to an enzyme • Leaves Nucleus: mRNA strand breaks away from DNA and enters the cytoplasm (where translation begins)
Translation • Process of converting information in mRNA into a sequence of amino acids that will make a protein
Steps of Translation • Ribosomes Attach: mRNA enters the cytoplasm where ribosomes of rRNA attach to it • rRNA reads mRNA: rRNA slides down the mRNA and signals to tRNA to bring the right amino acid • Start codon (AUG) signals where to begin making the protein
tRNA • tRNA has a clover-leaf shape with an anti-codon attached to one of the “leaves” and an amino acid attached to the “stem”
Steps of Translation (cont’d) • tRNA brings amino acids: tRNA with the correct anti-codon arrives and temporarily bonds to the codon of mRNA • rRNA slides and reads: rRNA continues to slide down the mRNA and reads next codon new tRNA
Steps of Translation (cont’d) • Amino acids join: an enzyme joins the amino acids (of tRNA) with peptide bonds • Once joined, the now amino acid free tRNA detaches from the mRNA strand • This process continues until a stop codon (UAA/UAG/UGA) is read
Transcription & Translation: END RESULT A chain of amino acids joined by peptide bonds PROTEIN
Transcription & Translation Sequence Animation of Protein Synthesis