1 PROTEIN SYNTHESIS. DNA and Genes DNA DNA contains genes, sequences of nucleotide bases These Genes code for proteins Proteins are used to build cells.

  • Published on

  • View

  • Download

Embed Size (px)


<ul><li><p>*PROTEIN SYNTHESIS</p></li><li><p>DNA and Genes</p></li><li><p>DNADNA contains genes, sequences of nucleotide basesThese Genes code for proteinsProteins are used to build cells and do much of the work inside cells </p></li><li><p>*Genes &amp; ProteinsProteins are made of amino acids linked together by peptide bonds20 different amino acids exist</p></li><li><p>*PolypeptidesAmino acid chains are called polypeptides</p></li><li><p>*DNA Begins the ProcessDNA is found inside the nucleusProteins, however, are made in the cytoplasm of cells by organelles called ribosomes</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 polypeptides (proteins)This process is called PROTEIN SYNTHESIS</p></li><li><p>RNA</p></li><li><p>*Roles of RNA and DNADNA is the MASTER PLAN </p><p>RNA is the BLUEPRINT of the Master Plan</p></li><li><p>*RNA Differs from DNARNA has a sugar riboseDNA has a sugar deoxyribose</p></li><li><p>*Other DifferencesRNA contains the base uracil (U)DNA has thymine (T)RNA molecule is single-strandedDNA is double-strandedDNA</p></li><li><p>*Structure of RNA</p></li><li><p>*. Three Types of RNAMessenger RNA (mRNA) copies DNAs code &amp; carries the genetic information to the ribosomesRibosomal RNA (rRNA), along with protein, makes up the ribosomesTransfer RNA (tRNA) transfers amino acids to the ribosomes where proteins are synthesized</p></li><li><p>*Messenger RNALong Straight chain of NucleotidesMade in the NucleusCopies DNA &amp; leaves through nuclear poresContains the Nitrogen Bases A, G, C, U ( no T )</p></li><li><p>*Messenger RNA (mRNA)Carries the information for a specific proteinSequence of 3 bases called codonAUG methionine or start codonUAA, UAG, or UGA stop codons</p></li><li><p>*Ribosomal RNA (rRNA)Globular in shapeMade inside the nucleus of a cellAssociates with proteins to form ribosomesSite of protein Synthesis</p></li><li><p>*The Genetic CodeA codon designates an amino acidAn amino acid may have more than one codonThere are 20 amino acids, but 64 possible codonsThree codons tell the ribosome to stop translating</p></li><li><p>*The Genetic Code Use the code by reading from the center to the outsideExample: AUG codes for Methionine</p></li><li><p>*Name the Amino AcidsGGG?UCA?CAU?GCA?AAA?</p></li><li><p>*</p></li><li><p>*Remember the Complementary BasesOn DNA: A-T C-GOn RNA: A-U C-G</p></li><li><p>*Transfer RNA (tRNA)Clover-leaf shapeSingle stranded molecule with attachment site at one end for an amino acidOpposite end has three nucleotide bases called the anticodon</p></li><li><p>*Transfer RNA</p></li><li><p>*Codons and AnticodonsThe 3 bases of an anticodon are complementary to the 3 bases of a codonExample: Codon ACU Anticodon UGAUGAACU</p></li><li><p>Transcription and Translation</p></li><li><p>*Pathway to Making a Protein (Central Dogma)DNA mRNA</p><p>tRNA (ribosomes)</p><p>Protein</p></li><li><p>*Protein SynthesisTwo phases: Transcription &amp; Translation Transcription is the process the creates mRNA, tRNA, and rRna!</p></li><li><p>*TranscriptionThe process of copying the sequence of one strand of DNA, the template strandmRNA copies the template strand</p></li><li><p>*Transcription </p></li><li><p>*Question:What would be the complementary RNA strand for the following DNA sequence?</p><p>DNA 5-GCGTATG-3</p></li><li><p>*Answer:DNA 5-GCGTATG-3RNA 3-CGCAUAC-5</p></li><li><p>*mRNA TranscriptmRNA leaves the nucleus through its pores and goes to the ribosomes</p></li><li><p>*TranslationTranslation is the process of decoding the mRNA into a polypeptide chainRibosomes read mRNA three bases or 1 codon at a time and construct the proteins</p></li><li><p>*RibosomesMade of a large and small subunitComposed of rRNA (40%) and proteins (60%)Have two sites for tRNA attachment</p></li><li><p>*Ribosomes PSite ASiteLargesubunitSmall subunit</p></li><li><p>Step 2 - ElongationAs ribosome moves, two tRNA with their amino acids move into site A and P of the ribosomePeptide bonds join the amino acids</p></li><li><p>*Initiation mRNAAUGCUACUUCGAanticodonhydrogenbondscodon</p></li><li><p>* mRNAAUGCUACUUCG1-tRNA2-tRNAUACGaa1aa2AUAanticodonhydrogenbondscodonpeptide bondElongation</p></li><li><p>* mRNAAUGCUACUUCG1-tRNA2-tRNAUACGaa1aa2AUApeptide bondRibosomes move over one codon(leaves)</p></li><li><p>*mRNAAUGCUACUUCG2-tRNAGaa1aa2AUApeptide bonds3-tRNAGAAaa3ACU</p></li><li><p>*mRNAAUGCUACUUCG2-tRNAGaa1aa2AUApeptide bonds3-tRNAGAAaa3ACU(leaves)Ribosomes move over one codon</p></li><li><p>*mRNAGCUACUUCGaa1aa2Apeptide bonds3-tRNAGAAaa34-tRNAGCUaa4ACU</p></li><li><p>*mRNAGCUACUUCGaa1aa2Apeptide bonds3-tRNAGAAaa34-tRNAGCUaa4ACURibosomes move over one codon</p></li><li><p>*mRNAACAUGUaa1aa2Uprimarystructureof a proteinaa3200-tRNAaa4UAGaa5CUaa200aa199terminator or stop codonTermination</p></li><li><p>*End Product The Protein!The end products of protein synthesis is a primary structure of a proteinA sequence of amino acid bonded together by peptide bonds</p></li><li><p>*Messenger RNA (mRNA)</p><p>****Like DNA, RNA is a polymer of nucleotides. In an RNA nucleotide, the sugar ribose is attached to a phosphate molecule and to a base, either G, U, A, or C. Notice that in RNA, the base uracil replaces thymine as one of the pyrimidine bases. RNA is single-stranded, whereas DNA is double-stranded.*Notice that in this chart, each of the codons (white rectangles) is composed of three letters representing the first base, second base, and third base. For example, find the rectangle where C for the first base and A for the second base intersect. You will see that U, C, A, or G can be the third base. CAU and CAC are codons for histidine; CAA and CAG are codons for glutamine.****</p></li></ul>


View more >