UNDERSTANDING HEREDITY PROTEIN SYNTHESIS 1. Genes & Proteins Genes - sequences of nucleotide bases Genes code for proteins Proteins - amino acids linked.

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<ul><li><p>UNDERSTANDING HEREDITY</p><p> PROTEIN SYNTHESIS*</p><p>copyright cmassengale</p></li><li><p>Genes &amp; ProteinsGenes - sequences of nucleotide basesGenes code for proteinsProteins - amino acids linked together by peptide bonds20 different amino acids exist</p><p>*</p></li><li><p>*Genes &amp; ProteinsAmino acid chains are called polypeptidesSo: Protein = polypeptideRibbon Structure ofMouse CholeraAntibody</p></li><li><p>*Starting with DNADNA - found inside the nucleusProteins are made in the cytoplasm of cells by organelles called ribosomesRibosomes may be free in the cytoplasm or attached to the surface of rough ER</p></li><li><p>*Starting with DNADNA s code must be copied and taken to the cytoplasmIn the cytoplasm, this code must be read so amino acids can be assembled to make proteinsThis process is called protein synthesis</p></li><li><p>RNA*</p><p>copyright cmassengale</p></li><li><p>*Roles of RNA &amp; DNADNA = COOKBOOK</p><p>RNA = KITCHEN CREW</p></li><li><p>*Roles of RNA &amp; DNARNA is a disposable copy of a portion of DNAIt is used to construct a proteinComparison of RNA and DNA</p><p>RNADNASugarRiboseDeoxyriboseNitrogen BasesC G A U(racil)C G A TStructureSingle HelixDouble Helix</p></li><li><p>*. Three Types of RNAMessenger RNA - mRNARibosomal RNA - rRNATransfer RNA - tRNA</p></li><li><p>*Messenger RNA (recipe)Long chain of nucleotidesMade in the nucleusTranscribes DNA &amp; leaves through nuclear poresCarries information for a specific protein to ribosome</p></li><li><p>* Ribosomal RNA (head chef)rRNA is a single strand 100 to 3000 nucleotides longGlobular in shapeMade in the nucleolus of a cellReads mRNA and assembles proteins</p></li><li><p>*Transfer RNA (kitchen staff)Clover-leaf shape</p><p>Single stranded molecule with attachment site at one end for an amino acid</p><p>Found out in the cytoplasm</p><p>Brings amino acid to ribosome</p></li><li><p>*</p></li><li><p>*The Genetic CodeCodon - a set of three RNA bases</p><p>Codon - designates a specific amino acid</p><p>An amino acid may have more than one codon and there are 64 codons</p></li><li><p>Transcription and Translation*</p><p>copyright cmassengale</p></li><li><p>*Protein SynthesisThe production or synthesis of polypeptide chains (proteins)Two phases: Transcription &amp; TranslationmRNA must be processed before it leaves the nucleus of eukaryotic cells</p></li><li><p>*TranscriptionThe process of mRNA copying the sequence of one strand of DNADuring transcription, RNA polymerase binds to DNA and separates the DNA strandsRNA Polymerase then uses one strand of DNA as a template to assemble nucleotides into RNA</p></li><li><p>*What would be the mRNA strand for the following DNA sequence?</p><p>DNA 5-GCGTATGAA-3</p><p>mRNA 3-CGCAUACUU-5</p></li><li><p>*STEPS OF TRANSCRIPTON:RNA polymerase binds to DNA just before code for protein beginsNucleotide bases are added to make strand of mRNARNA polymerase detaches from DNA and mRNAEnzymes proofread the mRNA sequence before it leaves nucleus</p></li><li><p>*mRNA TranscriptmRNA leaves the nucleus through its pores and goes to the ribosomes</p></li><li><p>*TranslationTranslation = the process of decoding the mRNA into a polypeptide chainRibosomes read mRNA three nucleotide bases or 1 codon at a time</p></li><li><p>STEPS OF TRANSLATION:mRNA transcript start codon AUG attaches to the ribosomeAmino acids are brought to the ribosome by tRNAtRNA plugs into the mRNA with an anticodonThe amino acids are attached like beads on a stringtRNA is released to cytoplasm; mRNA is disassembledStop codon tells ribosome to release protein*</p></li><li><p>*Summary of Protein SynthesisTranscriptionTranslation</p><p> DNA mRNA tRNA amino acid protein code copy anticode assemble product</p></li><li><p>Mutations are MistakesMistakes in gene code cause mistakes in the proteinThese mistakes are called mutationsIn protein synthesis mutations involving one base are called point mutationsSome mutations may do nothing to the final protein others may do serious damage*</p><p>***********************</p></li></ul>


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