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EDKP 395 (37)
Lecture

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Department
Kinesiology&Physical Education
Course
EDKP 395
Professor
Mark Brawley
Semester
Fall

Description
10/18/2012 12:23:00 PM Persistence hunting  Takes place during the hottest part of the day  Run up on the animals, scare them away, then track them o Marathon pace  not about getting there fast, just keep going  Goal- run animals into exhaustion Introduction  Metabolism- also includes absolute O2 consumption o Sum of all chemical reactions that occur in the body o Anabolic reactions  Synthesis of molecules  Ex. making muscle o Catabolic reaction  Breakdown of molecules  Ex. under dietary stress, breakdown of muscle for energy  Bioenergetics o Converting food stuffs (protein, carbs, fats) into biologically usable form of energy (ATP) using chemical pathways in the cell Note: flight is the most energy fueled type of locomotion Parts of a cell  Cell membrane o Sarcolemma- membrane in MUSCLE  Semi-permeable (CO2, O2, protons)  Phospholipid bi-layer  Provides separation b/w internal & external environments  Nucleus o Contains genes that regulate protein synthesis  Molecular biology plays a HUGE role in exercise physiology o Skeletal muscle  MANY NUCLEI  Vs typical cell which only has 1 (exception= RBC)  Cytoplasm o Fluid portion of cell\ o Separation b/w interior/extracellular fluid o Contains organelles  Mitochondria  Makes energy for cell  Contains its own DNA  Shows evidence that mitochondria ceom from eukaryotes Muscle adaptation  When a muscle gets injured, there are other cells (Muscle Stem Cells or Satellite Cells) located outside the true muscle fibres that are recruited to repair myosites that are broken o Nuclei of stem cell travels to center of cell Myofilaments  CONTRACTILE part of muscle  cells have compartmentalization  all the organelles are separate from each other and Exercise Science 10/18/2012 12:23:00 PM Molecular biology: study of molecular structures and events underlying biological process  Relationships b/w genes and cellular characteristics they control  Genes code for specific cellular proteins o Process of “protein synthesis” o Exercise training  leads to modifications in protein synthesis  Strength training results in increased synthesis of muscle contractile protein  Provides tools for understanding cellular response to exercise o Application: helps us devise other ways of getting benefits from people who can’t do exercise/certain types of exercise Biological Energy Transformation 10/18/2012 12:23:00 PM Occurs in the cell via series of chemical reactions  Endergonic: reactions REQUIRES ENERGY to be ADDED to the reactants to proceed o ENERGY INVESTMENT products contain more free energy than reactants o Ex. myosin cutting myofibril head off actin and chaning ATP ADP  Exergonic: reactions release energy as a result of the chemical process o ENERGY HARVEST o Ex. break down of glucose  Coupled (oxidation/reduction rxn): liberation of energy from exergonic reactions drives an endergonic reaction o Oxidation- process of REMOVING ELECTRON from an atom or molecule  Oxidizing agent – atom/molecule that accepts electron  Gets reduced: more negative  Ex. NAD, FAD o Reduction- process of ADDING ELECTRON to an atom/molecule  Reducing agent- atom/molecule that donates electron  Gets oxidized: more positive  Ex. NADH FADH  these events are ALWAYS COUPLED b/c a molecule can not be oxidized unless it donates electrons to another atom/molecule o Involve transfer of hydrogen atoms rather than free electrons  2 molecules play important role in hydrogen transferring  NAD- Nicotinamide-Adenine Dinucleotide  FAD- Flavin Adenine Dinucleotide + Structural formulas for NAD , NADH, FAD, FADH2  When NAD reacts with 2H, it binds to one of them and accepts the electron from the other o Forms NADH o  When FAD reacts with 2H, it binds to BOTH of them o Forms FADH2 o 10/18/2012 12:23:00 PM Catalysts that speed up cellular chemical reactions, and consequently increases the rate of product formation by decreasing the energy required to activate cellular chemical reactions (i.e. Activation Energy)  proteins  regulation of metabolic pathways  Selective- “lock & key mechanism” o “active site” site substrate binds to enzyme  specific shape to allow for only specific substrates to bind o once it binds, it is now called “enzyme-substrate complex” o Lock key mechanism  Substrate approaches the active site on enzyme  Substrate fits into active site, forming enzyme- substrate complex  This is the site where we see decreased energy of activation  Enzyme releases products  After formation of enzyme-substrate complex, energy required to activate cellular chemical reaction is REDUCED o Increases rate of product formation Classification of Enzymes (note: enzymes usually end in “ase”) Note: classification based upon type of reaction enzyme performs  Kinases o Add PHOSPHATE group  Activates enzyme  Modulates enzyme activity  Dehydrogenases o Remove hydrogen atoms  Oxidases o Catalyze oxidation-reduction reactions involving O2 o Important in mitochondria  Mitochondrial respiration is the primary source of energy for cell  Isomerases o Rearrangement of structure of molecule  think “isomers” = structurally different (like chem.) Factors that alter enzyme activity  Enzymatic activity = rate of product formation  Influenced by o Temperature  High temp increases enzymatic activity to a certain level  Note enzyme activity is less than max. at body temp (37 degrees)  Hypothermia/hyperthermia = decreased enzymatic activity  Q10 effect- every 10 degree increase = doubled enzymatic activity o pH  decrease (7.4-7.2) = decreased enzymatic activity = decreased ATP production (esp. oxidative phosphorylation)  drop in pH (more acidic) is MAIN CAUSE of muscle fatigue note: blue bar in both graphs represents optimal physiological conditions for higher enzymatic activity during exercise  increase in temp = increased enzyme acitivty = increased ATP  increase lactic acid = dec. pH (inc. acidity) = decreased ATP production Diagnostic value of measuring enzymatic activity in blood  Damaged cells release enzymes into blood o Blood enzyme levels indicate disease/tissue damage  Application o Elevated lactate dehydrogenase or creatine kinase in blood = myocardia infarction o Amylase pancreatitis o Aldolase  muscular dystrophy o Alkaline phosphatase  carcinoma of bone, obstructive jaundice o Myoglobin  severe muscle damage, heat injury  Note: measured in urine 10/18/2012 12:23:00 PM Types  Carbs  Protein  Fats During exercise carbohydrates and fats are primary source of nutrients  protein has a minor contribution  How to tell if using more carbs or fat o Compare CO2 production w/ O2 consumption at mouth during STEADY STATE o Typically  Low intensity- fat  High intensity- carbs  Fat is inefficient (hard for body to break down) Carbs  Made up of o Carbon o Hydrogen o Oxygen atoms  C6H12O6 o 1g carbs = 4 kcal  3 forms o monosaccharide- simple sugar  glucose, fructose o disaccharide- combination of 2 monosaccharides  sucrose (table sugar) o polysaccharide- complex carbs containing 3+ monosaccharides  starch (plants), glycogen (humans)  storage o stored in body as glycogen o glycogen  synthesized in muscle/liver cells  linking hundreds of glucose molecules using glycogen synthase o intracellular glycogen stores provide body with rapidly available form of energy  during exercise, intramuscular glycogen is broken down via glycogenolysis into glucose. The broken down glucose is used for ATP production and therefore muscle contractions  enzyme- phosphorylase  Glycogenolysis occurs in the liver, with free glucose being released into blood stream (blood sugar) for transportation to body tissues  Exercise metabolism o Glycogen is stored in muscle/liver cells o Glycogen synthesis is an ONGOING process in cells  Total glycogen stores in body are relatively small and can be depleted in a few hours of prolonged exercise  Hence theory of “carbo-loading” before an endurance exercise event (marathon)  glycogen is very large, which is why we can’t store a lot of it Fats  Made of carbon, hydrogen, and oxygen o Ex. palmitic acid C16H32O2  Excellent source of energy for PROLONGED exercise o 1g fat = 9 kcal  4 categories o fatty acids- primary type of fat used by cells for ATP production  stored in adipocytes (fat cells) an
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