BIOL 4610 1st Edition Lecture 3Outline of Current Lecture I. Structure of nucleic acidsII. TranscriptionIII. Molecular genetic techniquesIV. Genetic analysis of mutations to identify and study genesCurrent LectureChapter 4 – Basic Molecular Genetic Mechanisms 4-1. Structure of Nucleic Acids: 1. DNA: 2 polynucleic strands that are wound together2. Backbone: sugar and phosphate 3. Bases are held together by hydrogen bonds4. Base pairing rules: 5. CG (3 H bonds) and AT (2 H bonds)6. Negatively charged phosphateThe two DNA strands can separate from one another1. Melting temperature (Tm)- increase temperature to separate strands (separate the C and T or A and G)2. Ion concentrationsugar- phosphate backbone is negatively chargedin vitro you can use this to decrease ion concentration cation = less shielding of neg charges of two phospates next to each other => instability of strand and tends to break apart2. RNA – structure is similar to that DNA with exceptions:1. Sugar: an extra hydroxyl group –OH makes RNA much less stable than DNA2. Uracil in RNA, Thymine in DNA, but both pair with AdenineThese 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.3. RNA is single stranded4-2. Transcription of protein coding genes and formation of functional mRNARNA synthesized in 5’à3’ directionDomains: usually contained in 1-2 exonsUse 1 gene = create several, closely related proteinsdo this by removing exons called Isoform(alternative splicing)Fibronectin- secreted into extracellular space and holds cells together• Sometimes this isn’t good, in Hepatocyte in liver. Sinusoids are spaces for blood to travel without actually having a cell membrane or capillaryChapter 5 - Molecular Genetic Techniques1. Classical genetics: looking for observable differences1 Look at DNA and find the gene responsible for one set to be green and the other yellow2 Take gene and use it to make proteins 2. Reverse genetics: don’t need to see observable phenotype, but can go into database andidentify protein coding sequence to manipulate it to make an observable difference in the organism5.1. Genetic analysis of mutations to identify and study genesVocabularyMutant/mutation: change in very small part of DNA sequenceAllele- mutation that is naturally occurringGenotype: set of alleles (one from mom and one from dad) that we are looking at1. Same alleles= homozygous, exactly identical same set of alleles2. Allele A, allele B- heterozygotes, two different alleles of the same genePhenotype: physical traits that we attribute back to our genotypeInheriting mutations – recessiveusually a loss of functionyellow comes from mom and blue from dad.to inherent recessive alleles, must have both alleles being mutant1) Autosomal recessive –1) Any chromosome but a sex chrom.2) If you have the disease, both parents must have been heterozygotes (carriers) 2) X-linked recessive – 1. Sex chromosomes2. Almost always male offspring are affected bc must inherit X from mom3) Autosomal dominant- rareGet phenotype onset late in life (after reproductive age)Ex.
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