Amino Acids, Peptide Bonds and Protein Structure Study Guide 5

Type I vs Type II Diabetes: Type I • autoimmune disorder • pancreas doesnÕt produce insulin • insulin-dependent Type II • target cells fail to respond normally to insulin • r/t obesity & sedentary lifestyle666 • non insulin-dependent How does metformin help in the treatment of diabetes? • binds to Complex 1 of ETC and decreases ATP levels • Metformin decreases overall blood glucose by increasing movement of Glut4 transporters, & impedes gluconeogenesis in the liver. How can diabetes lead to glycation & AGEs? In pts with high blood sugar, the glucose surrounding proteins increases & makes it more likely that the glucose will link to the proteins During gluconeogenesis, how many ATP molecules are consumed for each glucose molecule produced? 6 Which molecule is regenerated via lactate production during anaerobic metabolism? NAD+ Why would a marathon runner consume a large meal of complex carbs the night before a race? To replenish cellular stores of glycogen. What are Advanced Glycation End Products, AGEs? glucose molecules linked to lipids or proteins w/o need for enzymes Why are blood glucose levels high in pts w/ unmanaged DM? Cells donÕt move enough Glut4 transporters to their cell membranes What type of molecule is glycogen? complex carbohydrate What happens in muscle cells when they respond to insulin? Glut4 transporters move to the surface of the cell. What is the function of fermentation in anaerobic metabolism? Fermentation regenerates the NAD+ needed for glycolysis. How does the proton gradient affect the pH of the mitochondrial metric & the inter membrane space? Concentration of protons in the inter membrane space is higher than in the matrix. Unit 7: Lipids lipids: • hydrophobic • functions include energy storage, hormonal signaling, neurotransmission, inßammation, pain regulation & synthesis of cell membranes • fats, phospholipids, waxes & steroids triglyceride function in energy storage: • stored in adipose tissue • long-term energy storage saturated fatty acid: • solid at room temp • butter, lard, shortening • contain only single bonds in hydrocarbon tails unsaturated fatty acid: • liquid at room temp • oils • contain double bonds in one or more tails triglycerides: • fat molecules • stored in adipose tissue • main form of energy storage in body cholesterol: • a steroid • important component of animal membranes • molecule from which other steroids are synthesized • synthesized in liver and through diet phospholipids: • phospholipid tail linked to glycerol • group containing phosphates replaces one of the tails • has hydrophilic head & hydrophobic tails • makes up most cell membranes micelle: helps body absorb lipids & fat soluble vitamins How does the length of a fatty acid affect its melting point & physical state at room temp? Length dictates their physical state & how much energy/heat is required to change their characteristics How do we label the different carbons & bonds in a fatty acid? • saturated fats: only have single bonds • unsaturated fats have double bonds in one or more tails How do we count the carbons in a full structure of a fatty acid? Carbons are counted from the Omega (methyl) end A structure formula? • each hydrocarbon chain is represented as a zigzag line • each bend represents a a carbon atom • hydrogens arenÕt shown Structural differences between saturated & unsaturated fats? • Saturated: contain only single bonds in hydrocarbon tails • Unsaturated: contain double bonds in one or more tails; has one fewer hydrogen atom on each double bonded carbon How does this affect their melting point & physical state at room temperature? • Saturated: solid at room temp; high melting point • Unsaturated: liquid at room temp; low melting point How can you recognize the structures of triglycerides, cholesterol & phospholipids? • triglyceride: one glycerol molecule with 3 fatty acid molecules • cholesterol: 4 fused carbon rings • phospholipids: hydrophilic head & hydrophobic tails What are each of their functions? • triglycerides: fats that provide cells with long-term energy • cholesterol: carbs that provide cells with quick energy • phospholipids: form cell membranes; form structures to enclose & transport fat throughout the bloodstream adipocytes: fat cells lipases: enzymes that use hydrolysis to break the ester bonds holding fatty acids to the glycerol backbone lipolysis: the breakdown of fats by hydrolysis to release fatty acids beta oxidation: • each round snips off a 2 carbon piece in the form of Acetyl CoA from the carboxyl end of the fatty acid • continues until fatty acid is left with last 2 carbon segment • each round generates: - 1 Acetyl CoA molecule - 1 NADH molecule - 1 FADH2 molecule ketoacidosis: • metabolic state caused by excessive generation of ketone bodies • occurs in uncontrolled diabetes & during prolonged fasting • Citric Acid Cycle is overloaded & canÕt use Acetyl CoA at rate itÕs made; excess CoA is channeled to make extra ketone bodies MCADD: • Medium Chain Acetyl CoA Dehydrogenase DeÞciency • lifelong condition, present at birth • disease r/t inability to digest medium length fatty acids with 6-12 carbons; pt cannot use fat as an energy source • s/s poor feeding, extreme sleepiness, seizures fatty acid synthesis: • 3 fatty acid molecules each joined to a glycerol by ester linkage • formed by dehydration reaction between carboxyl group & hydroxyl group oxaloacetate: • part of citric acid cycle • reacts with acetyl CoA to form citrate citrate: an intermediate in the citric acid cycle How do we break down a triglyceride? Beta-oxidation What happens to the different components of the triglyceride? • fatty acid tails are broken down into series of 2 carbon units that combine with coenzyme A to form acetyl CoA • acetyl CoA feeds into citric acid cycle How do we break down a fatty acid? lipolysis Where in the cell does this take place? cytoplasm What are the 3 products of beta oxidation? • a molecule of acetyl CoA • a molecule of NADH • a molecule of FAHD2 How do we calculate the amount of acetyl CoA produced from a fatty acid? Each round of beta oxidation generates one molecule of acetyl CoA. How do we calculate the number of rounds it takes to break it down completely? The number of rounds is ONE LESS than the total number of acetyl CoA molecules made. How do we calculate the amount of ATP produced? Each acetyl CoA produced can generate 14 ATP. (Acetyl CoA molecules x 14) What happens to the products of beta-oxidation once they are produced? • Acetyl CoA enters Citric Acid Cycle • NADH & FADH2 enter ETC to generate ATP via oxidative phosphorylation How & why are ketone bodies produced? In the liver, most acetyl CoA generated from fatty acids in fasting stage produces ketone bodies. They are carried into blood stream & provide crucial energy sources to nervous system tissues when glucose supply is limited. What is the molecule used for fatty acid synthesis? pyruvate How is this molecule exported from the mitochondria to the cytosol? Via aerobic respiration What is the committed step of fatty acid synthesis? Step 1 in fatty acid synthesis; Acetyl CoA is converted to Malonyl CoA. Which fatty acid pathways are controlled by insulin? • fatty acid synthesis • triglyceride synthesis Which are controlled by glucagon? • Beta-oxidation of fatty acids • lipolysis • ketone body production amphipathic: molecule that has both hydrophobic & hydrophilic regions; ex: phospholipids phospholipid bilayer: • two layers of phospholipids • hydrophobic interior (tails) & hydrophilic exterior (head) • critical component of cell membrane • allows selective passage into and out of cells plasma membrane: • provides protection for the cell • transports nutrients into cell • transports toxins out of cell • semi-permeable glycolipids: • membrane carbs, covalently bonded to lipids • important for cell-to-cell recognition & adhesion • maintain stability of cell • found on surface of lipid bilayer of cell membranes glycoproteins: • membrane carbs, covalently bonded to proteins • important for cell-to-cell recognition & adhesion • maintain stability of cell • found on surface of lipid bilayer of cell membranes Components of the plasma membrane: • phospholipids that form bilayer • proteins • carbs How do cells maintain the ßuidity of the plasma membrane when moved to colder or warmer temperature? Cholesterol acts as a buffer; prevents low temps from inhibiting ßuidity & high temps from increasing ßuidity eicosanoids: • signaling molecules • prostaglandins, thromboxanes & leukotrienes arachidonic acid: • an Omega-6 fatty acid • important starting material for 3 types of signaling molecules • stored as a component of phospholipids on cytoplasmic side of the plasma membrane chylomicron: • Ultra LDL • lipoprotein particle that carries triglyceride to the liver What does it mean for a nutrient to be essential? A nutrient is essential when it cannot be synthesized within the body. What are the fat soluble vitamins? K A D E What are the two essential fatty acids? • linolenic, Omega 6 fatty acid • linoleic acid, Omega 3 fatty acid How do we recognize that a fatty acid is essential? They are essential because they cannot be synthesized in humans. How do you recognize the structure of an eicosanoid? • Originate from polyunsaturated fatty acids with 20 carbons • furan ring structure What are its functions? Eicosanoids are lipid mediators; responsible for: • inßammatory response • gastric integrity • hypersensitivity • renal function • regulation of smooth muscle contraction • regulation of vasodilation • maintenance of platelet homeostasis How is it affected by aspirin? Aspirin prevents synthesis of known & unknown eicosanoid pathways. What diet would result in the production of ketone bodies in a healthy individual? A diet rich in trans fats and very low in carbs. What stimulates the beta-oxidation of fatty acids? Glucagon signal What situation would altering a protein lead to a disease state? A mutation in Acetyl CoA carboxylase can lead to brain damage. What process would be impaired in pts who have altered pancreatic lipase function? Catabolism of triglycerides. Which coenzymes are needed during beta-oxidation of fatty acids? NAD+, FAD & coenzyme A In the fasting state, glucagon is produced & up-regulates what process? Beta-oxidation Which molecule is the precursor to fatty acid synthesis? Acetyl CoA When given a normal and mutated DNA & RNA sequence, what steps are taken to determine the type of deletion that has occurred? What factors affect the use of pyruvate by the cell? Given the concentration of 02 (mmHg or torr), what is the saturation of myoglobin? What is the saturation of hemoglobin?