BCHM 3050 1st Edition Lecture 13Outline of Last Lecture I. General Mechanisms of Enzyme Regulation II. Three Main Types of Inhibitorsa. Competitiveb. Non-competitivec. UncompetitiveIII. Designer Drugs for AIDSIV. Covalent Modification of EnzymesV. Allosteric Regulation of EnzymesVI. Other Factors that Regulate Enzyme ActivityOutline of Current Lecture I. Nucleic AcidsII. Components of NucleotidesIII. Nitrogenous BasesIV. NucleosidesV. NucleotidesVI. Role of ATP in Energy MetabolismVII. Significance of ΔGVIII. Cyclic NucleotidesCurrent LectureThese 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.I. Nucleic Acidsa. Nucleic Acids – linear polymers of nucleotides that function in the storage and expression of genetic information, and its transfer from one generation to the nextb. Two types: RNA and DNAc. DNA is the blueprint of life and you are supposed to have the same DNA in each cell of the body (but mutations sometimes change this)d. Called Nucleic acids because of the overall negative chargee. RNA is the middle man; tales message from DNA and coverts it to proteinsII. Components of Nucleotidesa. Three components include a nitrogenous base, pentose sugar, and phosphateb. Nucleotide is the building block of DNAc. Know the structure of all 3 parts!d. Sugars tend to form ring-like structure and connect to a nitrogen atom and a phosphate group at the 5th carbon atome. Deoxyribose sugar lacks an oxygen atom (this is an ribose sugar)III. Nitrogenous Basesa. Purines – bigger and have a two ring structureb. Pyrimidines – smaller and have one ring structurec. Adenine and Guanine are the physiological purines found in DNA à Guanine has a double bond to oxygend. Xanthine and Hypoxanthine are deanimation products that sometimes need to be removed and replaced with adenine and guaninee. àcreated by removing the amino group and adding an oxygenf. àoccurs in the presence of waterg. Thymine and Cytosine are Pyrimidines in DNA à thymine has two double bond oxygens, and it is the only base to have a methyl group attached to ith. Thymine is only in DNA and Uracil is only in RNAi. AT and GC bondsj. Always find bases attached to a sugar; do not find free bases in naturek. Theobromine, theophylline, caffeine are all modifications of nitrogen bases (purines)IV. Nucleosidesa. Bond connecting the base to the sugar is always at carbon atom #1 à linkage where a sugar is attached to a base (or another sugar) is a glycosidic linkageb. Carbon atoms #2 and #3 have OH attached to it means that it’s a ribose sugar and only found in RNAc. If the sugar is missing an oxygen, then it is deoxyribose and found in DNAd. Nucleoside – sugar attached to a nitrogenous base (not a phosphate group)e. Thymine would not be attached to a ribose sugar because it is not part of RNAf. Adenosine competes with caffine for the same receptor à it is produced when we are sleepy but when we consume caffeine, it competes with adenosine and reverses the affect of adenosineg. Ex: Fungus attacks this caterpillar in the larval stage à secretion of a modification of Adenosine (doesn’t have an oxygen in the 3rd carbon position) and this disrupts the DNA synthesish. Zeatin and Zeatin Riboside are derived from AdenineV. Nucleotidesa. Phosphate group must be in the 5th carbon position to be considered a nucleotideb. Bond connecting the phosphate group to a carbon atom of the sugar is a phosphoester bondc. “Monophosphate” because it only has one phosphate group d. Carbons on sugars are labeled “5’, 4’, 3’, 2’, 1’” rather than just 5, 4, 3, 2, 1e. You will not find thymadinemonophosphate because it is a DNA molecule; instead it’ll be deoxythymadinemonophosphatef. All Deoxy-ribonucleotides all lack an oxygen atom at carbon atom #2g. “TP” stands of tri-phosphateh. ATP is very important and provides us with energyVI. Role of ATP in Energy Metabolisma. Catabolic reactions – larger molecules are broken down; also called exergonic rxns because they release energyb. Endergonic (anabolic) reactions use ATP as energy to complete the reactionVII. Significance of ΔGa. Exergonic reaction – free energy is negative; product has less energy than the reactant; favorable and spontaneous reactionsb. Endergonic reaction – free energy is positive; building up bonds; product has higher energy; “scavengers”c. Breaking down ATP is an exergonic reaction – release terminal phosphate group by breaking the phosphoanhydride bondd. This energy is used to build up other reactionse. Know that “-7.3 kcal/mole” is the energy released during ATP hydrolysisVIII. Cyclic Nucleotidesa. Signaling cascades – can have multiple targets and affect multiple parts of the bodyb. Primary messengers are often hormones and the secondary messengers are derivativesc. cGMP-mediated nitric oxide signaling is a relatively new signal cascade especially in plants.d. Much is known about cAMP-mediated signaling.e. Reaction between phosphate group and the 3rd carbon OH group à forms cyclic AMP (or cGMP)f. Purines (Adenine and Guanine) are the ones that form the cyclic
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