Biol 1543 1st Edition Lecture 8Outline of Last LectureI. Enzyme Activity Can Mirror Drug ActionII. Enzyme inhibitors block enzyme actionIII. Feedback inhibition regulates cell activityIV. Many poisons, pesticides, and drugs are enzyme inhibitorsV. Your liver and the smooth ERVI. Endplasmic Reticulum ComplicationsVII.Drug Abuse BasicsOutline of Current LectureI. Nucleotide monomersII. DNA and RNA are polymers of nucleotidesIII. DNA is a double-stranded helixIV. REPLICATIONV. The flow of genetic informationVI. From DNA to proteinVII.TRANSCRIPTIONVIII.Eukaryotic RNA is processed before leaving the nucleusIX. TRANSLATIONX. The genetic codeXI. REVIEWXII.Mutations can change the meaning of genesCurrent LectureI. Nucleotide monomersa. The monomers of nucleic acids arenucleotides composed of a sugar, phosphate,and nitrogenous baseb. The sugar and phosphate form the backbonefor the nucleic acid or polynucleotideII. DNA and RNA are polymers of nucleotidesa. DNA is a nucleic acid made of long chains ofnucleotide monomers.i. the sugar is deoxyribose (unique toDNA)b. DNA has four kinds of nitrogenous bases:i. A, T, C, and Gii. Two types(add picture)1. Pyrimidine and Purinec. RNA is also a nucleic acid, but has a slightly different sugar.i. sugar in RNA is ribosed. RNA uses U (Uracil) instead of T (the other 3 bases are same)Sugar-phosphatebackboneA NucleotideIII. DNA is a double-stranded helixa. James Watson and Francis Crick worked out the three-dimensionalstructure of DNA, based on work by Rosalind Franklin.b. The structure of DNA consists of two polynucleotide strands wrappedaround each other in a double helix.c. Hydrogen bonds between bases hold the strands together.d. Each base pairs with a complementary partner:i. A pairs with T, and G pairs with CIV. REPLICATIONa. DNA replication depends on specific base pairingi. Replication starts with the separation of DNA strandsii. Each strand becomes a template to assemble new nucleotides intocomplementary strands.b. Replication (aka duplication) is making an identical copyc. DNA replication is a complex process, due in part to the fact that someof the helical DNA molecule must untwist.d. … happens quicklyi. 50 nucleotides added every second (mammals)ii. 500 added every second in bacteriae. … with very few errorsi. Only about 1 of 1,000,000,000 nucleotides is mispairedii. DNA has a proofreading enzymeiii.DNA also has a repair enzymeV. The flow of genetic informationa. A genotype is an organism’s genetic makeup.b. A phenotype is the characteristic we see.i. the manifestation of the genetic information (what it becomes)c. The DNA genotype is expressed through proteins, giving us thephenotypes we see.d. A particular gene is a long line of nucleotides.i. A unit of informatione. Genes specify how to buildpolypeptides (proteins).i. Genes to proteinsVI. From DNA to proteina. The DNA of the gene is transcribedinto RNA, which is translated into thepolypeptide.i. two main stages of expressinginformation in DNA1. Transcription (in thenucleus)(DNA to RNA)2. Translation (RNA intoprotein)(in the Cytosol)VII.TRANSCRIPTIONa. Transcription produces geneticmessages in the form of RNA.b. The DNA helix unzips and RNA nucleotides line up along one strand of theDNA, following base pairing rules (A+U, C+G).c. As the single-stranded RNA peels away from the gene, the DNA strandsthen rejoin.d. Three stages of transcription:i. Initiation- the RNA polymerase hooks on to the DNA to starttranscription at the promoter DNA sectionii. Elongation- Moves along the DNA to copy the codeiii.Termination- Stops at the terminator section on the DNAVIII.Eukaryotic RNA is processed before leaving the nucleusa. Transcriptioni. RNA that is used to make proteins = mRNAii. “messenger RNA” carries the genetic message from DNA out of thenucleusb. Translationi. a ribosome attaches to mRNAii. tRNA translates the message to a polypeptideIX. TRANSLATIONa. Genetic information written in codons is translated into amino acidsequencesi. The “words” of the DNA “language” are triplets of bases calledcodons.ii. The codons in a gene specify the amino acid sequence of apolypeptide.1. Three codons will code for one amino acidiii.Nearly all organisms use exactly the same genetic code.X. The genetic codea. Each codon is translated into one amino acid.XI. REVIEWa. The flow of genetic information in the cell: DNA→RNA→proteini. The sequence of codons in DNA spells out the structure of apolypeptide.XII.Mutations can change the meaning of genesa. Mutations are changes in the DNA base sequence caused by some errorin DNA or by mutagens.i. Mutagens are something capable of causing a genetic change.Such as radiationb. Substituting, inserting, or deleting nucleotides alters a gene with varyingeffects on the organismi. Three primary ways genes are altered1. substituting of a nucleotide2. insert of an extra nucleotide3. delete a nucleotidec. Erythrocytes = red blood cellsd. by-concave disc is the shape of the normal red blood celle. in sickle cells they are sickle shaped (like a quarter moon)i. the shape does not allow for very good oxygenation of the tissuef. Symptomatic and supportive (this is how they take care of sickle-cellbecause there is no