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Macromolecules and MetabolismMacromolecules • Four types of macromolecule • Carbon based molecules • Each formed of monomers • Monomers join in a condensation reaction to form polymersProteinsAmino Acids • Protein monomer • Amide side group and carboxyl side group • Each amino acid has a different side group 'R'Peptide bond • Condensation reaction • Water molecule expelledHierarchal structure of proteinsPrimary Structure • The sequence of amino acids in the polypeptide chain • The chain exhibits directionality • Written from N-terminus to C- terminusSecondary structure • Localised areas of the polypeptide chain form alpha helices and beta pleated sheets • 60% of the polypeptide chain adopts one of these structures • Hydrogen bonds form between partially charged atomsAlpha helices • Spiral structure • Amino acid residues extend outwards • Right-handed helix • Complete turn of the spiral every 3.6 residues • Hydrogen bond between the carbonyl oxygen and amide hydrogen of residues 4 amino acids apartBeta Pleated Sheet • Chain winds back on itself • Hydrogen bonds between adjacent strandsTertiary Structure • The 3D structure of the protein • Determined by the amino acids present in the primary structure • Hydrophobic interactions, Hydrogen bonds, Disulphide bridges, Van der waals interactions and ionic bonds.Quaternary Structure • Two or more polypeptide chains come together • Joined by the same bonds found in the tertiary structureCarbohydratesMonosaccharides • Monosaccharides are carbohydrate monomers • e.g. Glucose, Fructose, Galactose • Can be separated into aldoses and ketosesGlycosidic Bonds and disaccharidesAlpha and Beta Glucose • Glucose is a monosaccharide • Between the two forms, there is a slight difference • Alpha glucose is found in glycogen and starch • Beta glucose is found in celluloseStarch and Glycogen • Large storage molecules • Starch in plants, glycogen in animals • Insoluble so no osmotic pressure • Starch is formed of amylose and amylopectin • Glycogen is more highly branched than starch • Straight chains form a toghtly coiled helix stabilised by hydrogen bondsCellulose • Found in plant cell walls • Made up of beta glucose • No branches • Every other glucose moelcule is inverted • Hydrogen bonding between cellulose straight chains • Many hydrogen bonds mean cellulose has a high tensile strengthLipidsWhat is a lipid? A substance that is: • Made up of carbon, hydrogen & oxygen • Insoluble in water but soluble in organic solvents (e.g. alcohol)Triglycerides • Energy rich • (hydrophobic)water • Source of water when broken down • Different properties depending on fatty acid structureTriglycerides • Energy rich • (hydrophobic)water • Source of water when broken down • Different properties depending on fatty acid structurePhospholipids • Polar • Different properties when combined with other molecules e.g. carbohydrates • Forms phospholipid bilayerCholesterol • Insoluble in water (hydrophobic) • Small, flat shape • Provides structural integrity to phospholipid bilayer • Forms steroid sex hormones, growth hormones and bile saltsNucleic acidsA nucleotide Consist of a: • Phosphate group • Pentose sugar • Nitrogen-containing baseA nucleotide Consist of a: • Phosphate group • Pentose sugar • Nitrogen-containing baseA nucleotide Consist of a: • Phosphate group • Pentose sugar • Nitrogen-containing baseA nucleotide Consist of a: • Phosphate group • Pentose sugar • Nitrogen-containing baseA nucleotide Consist of a: • Phosphate group • Pentose sugar • Nitrogen-containing baseA TP (adenosine triphosphate) • Energy currency of the cell • High “phosphorylation potential”DNA v RNA • Nucleotides join via condensation reaction • Consist of sugar-phosphate backbone, with inward facing bases • DNA consists of 2 anti-parallel polynucleotide chains, unlike RNA which consists of 1. .DNA v RNA • Nucleotides join via condensation reaction • Consist of sugar-phosphate backbone, with inward facing bases • DNA consists of 2 anti-parallel polynucleotide chains, unlike RNA which consists of 1.DNA v RNA • Nucleotides join via condensation reaction • Consist of sugar-phosphate backbone, with inward facing bases • DNA consists of 2 anti-parallel polynucleotide chains, unlike RNA which consists of 1.MetabolismWhat is Metabolism? Answers in the chatWhat is Metabolism? • Metabolism is term for all the chemical reactions that occur in cells • i.e. metabolism includes the breakdown of sugars for energy…. • ….but also includes the production of glycogen and protein synthesis. • This lecture section will focus on the metabolic process: Cellular RespirationTypes of Respiration Aerobic Anaerobic + O 2 - O2 Full respiration mechanism Glycolysis only Produces H O2and CO 2 Produces Lactic Acid and CO 2 Releases more energy Releases less energy Why do we need both? - We fluctuate between periods of oxygen surplus and oxygen deficiency (e.g. rest an exercise) - During periods of oxygen surplus, we want to maximise our energy released:glucsoeratio - During periods of oxygen deficiency, we still need useable energy to be released by whatever mechanism possible Aerobic respiration stage Glucose Glycolysis 2*Pyruvate Link 2*Acetyl-CoA 2*ATP, 2*NADH 2*NADH 6* NADH, Oxidative Phosphorylation 2* FADH 2 Krebs’ Cycle 2* ATP 28* ATP 32* ATP in totalGlycolysis This process modifies absorbed sugars to begin releasing energy and converts them into a format useable for later processes Most commonly this occurs with Glucose as the 6C sugar - This forms G6P when phosphorylated - And then Triose Phosphate (TP) upon splitting End products are - 2 molecules of pyruvate (3C) - 2 molecules of reduced NAD+ (NADH) - (Net) 2 molecules of ATP Aerobic respiration stage Glucose Glycolysis 2*Pyruvate Link 2*Acetyl-CoA 2*ATP, 2*NADH 2*NADH 6* NADH, Oxidative Phosphorylation 2* FADH 2 Krebs’ Cycle 2* ATP 28* ATP 32* ATP in totalLink Reaction This stage converts Pyruvate to Acetyl-CoA Pyruvate is first decarboxylated (removi2g CO ) to acetate - This reduces NAD+ to NADH The cofactor CoA is then added to acetate to form acetyl- CoA (2C) Remember, this process occurs twice per glucose molecule Aerobic respiration stage Glucose Glycolysis 2*Pyruvate Link 2*Acetyl-CoA 2*ATP, 2*NADH 2*NADH 6* NADH, Oxidative Phosphorylation 2* FADH 2 Krebs’ Cycle 2* ATP 28* ATP 32* ATP in total Krebs Cycle This process uses Acetyl-CoA (2C) produced in the Link reaction, by reacting it with oxaloacetate (4C) to form Citric acid (6C) - Also reforming CoA Citric acid will then undergo a series of reactions (decarboxylation-redox, isomerism and functional group reactions) to reform oxaloacetate This process will produce: - 3* NADH and 1* FADH by redox 2 - 1*ATP by substrate level phosphorylation of ADP Aerobic respiration stage Glucose Glycolysis 2*Pyruvate Link 2*Acetyl-CoA 2*ATP, 2*NADH 2*NADH 6* NADH, Oxidative Phosphorylation 2* FADH 2 Krebs’ Cycle 2* ATP 28* ATP 32* ATP in total Oxidative Phosphorylation During this process, reduced cofactors (NADH and FADH)2are oxidisedto release energy for ATP production NADH releases it's electrons/hydrogen at Complex 1 FADH 2eleased them for complex 2 - As the electrons travel along the electron transport chain (ETC) they release energy which allows pumping of hydrogen ions (H ) into the intermembranous space The H ions accumulate leading to a concentration gradient. The ions flow through a transporter (ATP synthase) which uses this flow to convert ADP + Pi to ATP Oxidative Phosphorylation The electrons released from the cofactors, with free protons, are then used to convert O2into water, 2H + O + 2e à 2H O 2 2 In total 2.5 ATP molecules are produced per NADH oxidation, and 1.5 ATP molecules are produced per FADH oxidation. 2 Aerobic respiration stage Glucose Glycolysis 2*Pyruvate Link 2*Acetyl-CoA 2*ATP, 2*NADH 2*NADH 6* NADH, Oxidative Phosphorylation 2* FADH 2 Krebs’ Cycle 2* ATP 28* ATP 32* ATP in totalAnaerobic respiration • Without O the electron transport chain (in oxidative phosphorylation cannot process the NADH and FADH produced by the Krebs Cycle, 2 Link reaction and Glycolysis. • The process ceases and the cell switches to an alternative mode of generating energy – Anaerobic respiration • During Anaerobic respiration glycolysis continues as normal however once Pyruvate is produced (with the net yield of 2 ATPs) it does not enter the link reaction. Recycling NAD During Glycolysis, NADH is produced when triose phosphate is converted to pyruvate (this is where ATP is also produced) As the NADH cannot be utilized in the ETC it is recycled back to NAD+ by converting pyruvate to lactate This allows the NAD+ to react with another Triose phosphate molecule to allow continued production of ATPAny Questions?