PLB 115 1st Edition Lecture 14Outline of Last LectureI. Down SyndromeII. Abnormalities & Non-disjunctionIII. Gamete ProductionIV. Meiosis I (PMAT1)a. Prophase Ib. Metaphase Ic. Anaphase Id. Telophase IV. CytokinesisVI. Meiosis IIa. Prophase IIb. Metaphase IIc. Anaphase IId. Telophase IIVII. Sexual ReproductionVIII. Mitosisa. Interphasei. G1ii. Siii. G2IX. Prophasea. Late prophaseX. MetaphaseXI. AnaphaseXII. TelophaseXIII. CytokinesisXIV. Mitosis vs MeiosisOutline of Current LectureI. DNA StructureII. DNA FunctionsIII. DNA ReplicationIV. Base Pairing ProcessV. DNA CodeVI. DNA VS RNAThese notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.VII. Protein SynthesisVIII. TranscriptionIX. TranslationX. Ribosomes & TranslationXI. Translation InitiationXII. Translation ElongationXIII. Translation TerminationXIV. Universal Genetic CodeXV. Control of Protein SynthesisXVI. Control of Protein QuantityXVII. Alternative SplicingXVIII. Mutations & Protein SynthesisXIX. Point MutationsXX. Sickle Cell AnemiaXXI. Insertions and DeletionsXXII. Mutations Caused by VirusesCurrent LectureDNA StructureDNA= Nucleic acido Nucleic Acids=  Large polymers made of nucleotides  Sugar molecule (Deoxyribose for DNA & Ribose for RNA)o A phosphate group- Nitrogenous bases held together by hydrogen bonds that only pair with each other Adenine & Thymine Cytosine & Guanine - Double strandedDNA Functions**Able to do this because of unique structure**- Stores genetic information- Directs protein synthesis- Chemically changes genetic characteristics (mutations)- Replicates itselfDNA ReplicationDNA is copiedo Done BEFORE cell division, providing new daughter cells with correct genetic info.- Relies on base-paring rules: Always & only A&T, C&GBase Pairing Process- Done by DNA Polymerase & other enzymeso Helicase binds to DNA & forms a “replication bubble” by separating 2 DNA strandso Polymerase builds new DNA strands that pair with each old DNA strand** DNA polymerase finishes a segment of new DNA & checks its work &corrects mistakes**DNA Code- Order of nucleic bases in the DNA molecules is the genetic information that codes for proteins- Each three-letter word codes for a specific amino acid- Order of amino acids in the protein is determined by the order of nucleotides in DNADNA VS RNA- RNA uses ribose sugar instead of deoxyribose- Almost same nucleotide bases: EXCEPT Adenine pairs with Uracil/ not Thymine (like DNA)- RNA made in nucleus & transported to cytoplasm (DNA stays in the nucleus)- RNA is single stranded (DNA is double-stranded)- Three types of RNA participate in protein synthesiso mRNA o tRNA o rRNAProtein Synthesis- Before ** DNA info must be copied into RNA (Transcription)**- Information in the RNA then used to make the protein (Translation)Transcription- DNA is used as a template to make RNAo Occurs in Nucleuso Done by RNA polymerase & follows base pairing rules RNA polymerase separates the two strands of DNA- Only one of the two strands will be used to create the RNAo The coding strand & other DNA strand = non-coding strandOnly a segment (gene) of DNA strand will be used to create each RNAEach gene…- Begins with promotero RNA polymerase binds to the promoter to start building an RNA strand- Ends with terminator sequenceo RNA polymerase stops transcribing at terminator sequenceTranslation- mRNA carries the recipe for making the protein- tRNA & rRNA used to read the recipe & build amino acid chain** Codons = sets of 3 nucleotides that code for specific amino acids**- tRNA reads codons & brings the correct amino acidsRibosomes & TranslationRibosomes build proteins (found free-floating in cytoplasm, bound to endoplasmic reticulum)- rRNA is found in ribosomes- mRNA is read on ribosomesTranslation Initiation- Small ribosomal subunit binds to beginning of the mRNA & searches start codon: AUG - tRNA brings the first amino acid- Anticodon in the tRNA matches with an mRNA codon- (each tRNA carries a specific amino acid based on its anticodon)- AUG (Stat codon) then binds to a tRNA that carries a methionine- Large ribosomal subunit joins the complex - Translation elongation can now startTranslation Elongation- Next tRNA binds with the next mRN codon- Ribosome adds amino acid to the growing polypeptide- Ribosome moves down to next codon**This process repeats itself- for each new step, a new amino acid is added to (growing) proteinTranslation Termination- Elongation continues until ribosome encounters a stop codon (UAA, UAG, UGA)- Release factor binds to the stop codono Ribosome releases polypeptideo Ribosomal subunits separate & release mRNA mRNA can be translated again by another ribosomeUniversal Genetic Code- Nearly all organisms studied to date use the same genetic code- Process of making proteins from the information in DNA is used by nearly all cells- Because of this, we are able to use bacteria as factories to make massive amounts of proteinso Insulin, etc.Control of Protein Synthesis- Gene expression is how cell makes a protein from info in a gene**Cell types are different from one another b/c they express different sets of genes**o Have different sets of proteins- Cells control gene expression in response to different environmental conditionso *Gene expression can always change Quantity of a protein can change Amino acid sequence of a protein can changeControl of Protein Quantity- Cells can regulate how much of a given protein is made by controlling how much mRNA is available for translationDo this by:o Regulating how tightly the chromatin is coiled in a certain region  The tighter the chromatin is coiled, the less likely a gene in that region willbe transcribedo By increasing/decreasing rate of transcription of the gene by enhancer & silencerregions on the DNAo Through the binding of transcription factors Proteins bind to promoter & help RNA polymerase bind & transcribeo By limiting the amount of time the mRNA exists in the cytoplasm Some mRNA molecules=more stable & will exist longer in the cytoplasm, making more proteinEukaryotic cells can use one gene to make more than one protein- Non-coding sequences (introns) are scattered throughout the sequenceAlternative Splicing Splicing: After transcription, introns must be cut out & coding regions (exons) must be put back together- Different combinations of exons from a single gene can be joined to build a number of