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Protein Synthesis. Prior Knowledge. Protein: Large complex molecule that is essential to all life Synthesis: to build, put together Protein Synthesis: building of proteins Proteins are made from amino acids Sequence of nucleotides code for specific proteins
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Prior Knowledge • Protein: Large complex molecule that is essential to all life • Synthesis: to build, put together • Protein Synthesis: building of proteins • Proteins are made from amino acids • Sequence of nucleotides code for specific proteins • Enzymes are proteins which control the chemical reactions in a cell • DNA contains the codes therefore controls the cells. • Ribosome: Place where proteins are assembled.
RNA • Ribonucleic Acid • “the workers” • Take instructions from the DNA and build the proteins one amino acid at a time. • Single Stands • Sugar is Ribose • Bases: Adenine, Uracil (pairs with Adenine), Guanine, Cytosine • Three Types: • mRNA • tRNA • rRNA
Types of RNA • Messenger RNA (mRNA) • Brings the DNA’s instructions from the nucleus to the cytoplasm to the ribosome. • Ribosomal RNA (rRNA) • Binds to mRNA and uses the instructions to assemble amino acids. • Transfer RNA (tRNA) • Brings amino acids to the ribosome to be assembled.
Transcription First step in the Protein Synthesis method • DNA Helicase unzips the DNA • Free RNA nucleotides pair with complimentary bases. • A to U; C to G • One portion of DNA is copied. • RNA nucleotides bond together and form *ONE mRNA strand. * Different in DNA replication…two new strands are formed in DNA replication. • mRNA strands leaves the nucleus and heads to the ribosomes. • DNA strands reconnect.
Genetic Code • mRNA contains a code using A’s, U’s, C’s, G’s. • Complete instructions for building a protein • Code must be converted into protein language
Genetic Code • Codon: group of THREE nitrogenous bases code for ONE amino acid. • Ex: UUU codes for Phenylalanine to be placed into a protein. • Ex: UAA is a stop codon • Ex: AUG is a start codon • 64 combo’s are possible • More than one codon can code for one amino acid • UAU & UAC are both Tyrosine codons • One Codon only codes for 1 amino acid • UAU only codes for Tyrosine • UCU only codes for Serine
Genetic Code ALL ORGANISMS USE SAME GENETIC CODE!!! First Base in Codon: C Second Base in Codon: A Third Base in Codon: U So…CAU codes for His (Histidine) What does UAG code for? Stop What does AGC code for? Serine
DNA Code: T A C /A C G /A T A/G T G /A T T A U G U G C U A U C A C U A A mRN Strand Protein Start Cystine Tyrosine Histidine Stop
Translation Second Step in Protein Synthesis • Occurs at the ribosomes • Ribosome attaches to mRNA like a clothespin • Sequence of bases is converted into sequence of amino acids • Use Genetic Code • Ex: CAU to Histidine • Ex: UAG to Stop etc… • tRNA brings needed amino acids to the ribosome to build the protein.
Translation • tRNA has two sides • amino acid side • Nitrogenous base side • Anticodon: 3 bases of tRNA • on opposite end of amino acid • Pair up with mRNA bases What is the anticodon for the following mRNA strand? A U G U A C
Translation • Amino acids bond with each other • Forms polypeptide bonds or PROTEINS!! • This Process continues until a STOP codon is reached