Pyhisoolgy is dfenied as a barcnh of sicnece daeilng wtih the sutdy of nroaml fnutcion of lvinig ogrnasim. hmuan Pyhisoolgy is dfenied as a barcnh of sicnece daeilng wtih the sutdy of dfiefernt ssyetm of the hmuan bdoy lkie criucalotry, rseiparotry, dgiseitve, msuucalr ssyetm, etc Wliilam Hraevy( ) is rgeraedd as the ftaehr of mdoren Pyhisoolgy. Eexcrsie Pyhisoolgy is a sicnece taht tlels us, how the hmuan bdoy fnutcoins, ajdsut and aadpt, wehn epxsoed to vraeid dgeere of pyhisacl atcvitiy or tarninig. Eexcrsie Pyhisoolgy is the sutdy of the aucte rseopsnes and crhnoic aadtptaoins to a wdie-rnage of pyhisacl Eexcrsie cnoiditnos.

Mtepayhiscs is the sutdy of ctacaohalimne tarsnmanitaoin and bteoaixaditon. Lpiid mtebalosim is the porudtcoin of aecytcleoznmye. Aecytclohilne is konwn as nueorrtnamstietr wihch hleps in msulce cnortcaiton.

Energy Metabolism

Energy metabolism Energy from the food we eat is stored in the form of ATP ATP is broken down to liberate the energy used to cause muscle contractions Anabolism— “to build up”; such as the use of amino acids to make proteins, which contribute to muscle mass Catabolism— “to break down”; such as breaking down glycogen to glucose molecules

Energy is stored in food in the form of carbohydrates, Fats and proteins. These basic food components can be broken down in out cells to release the stored energy. Energy production is both time and intensity related. Running at a very high intensity, as in sprinting, means that an athlete can operate effectively for only a very short period. Running at a low intensity, as in gentle jogging, means that an athlete can sustain activity for a long period.

The ATP molecule is composed of three components. At the centre is a sugar molecule, ribose (the same sugar that forms the basis of RNA). Attached to one side of this is a base (a group consisting of linked rings of carbon and nitrogen atoms); in this case the base is adenine. The other side of the sugar is attached to a string of phosphate groups. These phosphates are the key to the activity of ATP.

Catabolism and Anabolism Catabolic reactions breakdown complex organic compounds providing energy (exergonic) glycolysis, Krebs cycle and electron transport Anabolic reactions synthesize complex molecules from small molecules requiring energy (endergonic) Exchange of energy requires use of ATP (adenosine triphosphate) molecule.

ATP - Adenosine Triphosphate: a complex chemical compound formed with the energy released from food and stored in all cells, particularly muscles. Only from the energy released by the breakdown of this compound can the cells perform work. The breakdown of ATP produces energy and ADP. CP - Creatine Phosphate: a chemical compound stored in muscle, which when broken down aids in the manufacture of ATP. The combination of ADP and CP produces ATP.Creatine Phosphate LA - Lactic acid: a fatiguing metabolite of the lactic acid system resulting from the incomplete breakdown of glucose.Lactic acid O2 means aerobic running in which ATP is manufactured from food mainly sugar and fat. This system produces ATP and is the prime energy source during endurance activities

ATP is the source of energy for muscle contraction Producing enough ATP is essential to performance Adaptations to exercise training involve energy metabolism The metabolic demands of training are important in designing training or exercise prescriptions

Adenosine Triphosphate (ATP)

The Alactic Anaerobic Energy System This energy system is the dominant source of muscle energy for high intensity explosive exercise that lasts for 10 seconds or less. For example, the alactic anaerobic energy system would be the main energy source for a 100 m sprint, or a short set of a weightlifting exercise. It can provide energy immediately, it does not require any oxygen (that's what "anaerobic" means), and it does not produce any lactic acid (that's what "alactic" means). It is also referred to as the ATP-PCr energy system or the phosphagen energy system.

Definitions of anaerobic and aerobic metabolism Aerobic metabolism is the production of ATP with oxygen. Anaerobic metabolism is the production of ATP without oxygen.

ATP production ATP can be produced aerobically or anaerobically Most physical activities involve both aerobic and anaerobic metabolism

DurationClassification Energy Supplied By 1 to 4 secondsAnaerobicATP (in muscles) 4 to 10 secondsAnaerobicATP + CP 10 to 45 secondsAnaerobic ATP + CP + Muscle glycogen 45 to 120 secondsAnaerobic, LacticMuscle glycogen 120 to 240 secondsAerobic + Anaerobic Muscle glycogen + lactic acid lactic acid 240 to 600 secondsAerobic Muscle glycogen + fatty acids

Proportion of Aerobic / Anaerobic Production of Energy (ATP) Duration of Maximal Exercise % Anaerobic % Aerobic 1-3 sec sec sec min min min min min595 1 hour298 2 hours199

Energy Systems for Selected Sports % ATP Contribution by Energy Systems Sport/ActivityATP-PCGlycolysisAerobic Baseball80155 Basketball8010 Field hockey6020 Football90100 Gymnastics90100 Rowing Swim (50m)9550 Swim (100m)80200 Swim (200m)30655 Swim (400m)2040 Swim (1.5km)102070

continued Tennis Field Events90100 Run 400m40555 Run 800m Run 5km22870 Marathon0298 Volleyball90100 Wrestling45550

Approximate percentages of aerobic and anaerobic contributions to ATP production

Approximate percentages of aerobic and anaerobic contributions to ATP production (cont.)

The three characteristics of enzymes Speed up or catalyze a reaction Are not changed by the reaction they cause Do not change the result of the reaction

Lactic Anaerobic Energy System This system is the dominant source of muscle energy for high intensity exercise activities that last up to approximately 90 seconds to 2 minutes. For example, 800 m sprint, 400 m. Essentially, this system is dominant when your alactic anaerobic energy system is depleted but you continue to exercise at an intensity that is too demanding for your aerobic energy system to handle. this system is also anaerobic and so it does not require any oxygen. However, this system produce lactic acid. It is also referred to as the lactic acid system or the anaerobic glycolytic system.

Summary of aerobic metabolism Of carbohydrates Anaerobic glycolysis precedes aerobic phases of ATP production Of fats (fatty acid oxidation) 1. Fatty acids are liberated from storage as a part of triglycerides 2. Long carbon chain fatty acids are metabolized through beta oxidation into two carbon acetyl coenzyme A molecules 3. These enter the Krebs cycle and go through the ETS for ATP production Of protein 1. Amino acids are converted into keto acids by the liver or muscle 2. Keto acids form substances that produce ATP through the Krebs cycle and ETS

Fat, carbohydrate, and protein can be used to produce ATP aerobically

Selected coenzymes in energy metabolism

Anaerobic ATP production ATP can be produced anaerobically through two pathways: ATP-PC system Anaerobic glycolysis

The three primary enzymatic reactions that occur in the ATP-PC system 1. ATPADP + inorganic phosphate (Pi) + energy 2. PC + ADPATP + C 3. 2ADP ATP + AMP Myosin ATPase Creatine Kinase (CK) Adenylate Kinase (AK)

Anaerobic glycolysis The primary system for ATP production for activities that last from approximately 20– 30 seconds to two to three minutes The breakdown of glucose to lactate without the use of oxygen

Anaerobic glycolysis involves the breakdown of glucose to lactate.

This is the second stage, and the products of this stage of the aerobic system are a net production of 2 ATP, 1 carbon dioxide Molecule, three reduced NAD molecules, 1 reduced FAD molecule (The molecules of NAD and FAD mentioned here are electron carriers, and if they are said to be reduced, this means that they have had a H+ ion added to them). The things produced here are for each turn of the Krebs Cycle. The Krebs cycle turns twice for each molecule of glucose that passes through the aerobic system - as 2 pyruvate molecules enter the Krebs Cycle. In order for the Pyruvate molecules to enter the Krebs cycle they must be converted to Acetyl Coenzyme A. During this link reaction, for each molecule of pyruvate that gets converted to Acetyl Coenzyme A, an NAD is also reduced. This stage of the aerobic system takes place in the matrix of the cells' mitochondria.carbon dioxidepyruvate

The Krebs cycle occurs within the mitochondria of the muscle fiber The Krebs cycle is a series of reactions which occurs in the mitochondria and results in the formation of ATP. The pyruvic acid molecules from glycolysis undergo oxidation in the mitochondrion to produce acetyl coenzyme A and then the Krebs cycle begins.

Three major events occur during the Krebs cycle. One guanosine triphosphate (GTP) is produced which donates a phosphate group to ADP to form one ATP; three molecules of Nicotinamide adenine dinucleotide (NAD) and one molecule of flavin adenine dinucleotide (FAD) are reduced. Although one molecule of GTP leads to the production of one ATP, the production of the reduced NAD and FAD are far more significant in the cell's energy generating process because they donate their electrons to an electron transport system that generates large amounts ATP.

The electron transport system The part of aerobic metabolism where 34 of the 38 ATP are produced

What is the respiratory chain? The Krebs cycle and the electron transport system (ETS), where ATP is produced and oxygen is utilized.

Oxidative Phosphorylation - This is the last stage of the aerobic system and produces the largest yield of ATP out of all the stages - a total of 34 ATP molecules. It is called 'Oxidative Phosphorylation' because oxygen is the final acceptor of the electrons and hydrogen ions that leave this stage of aerobic respiration (hence oxidative) and ADP gets phosphorylated (an extra phosphate gets added) to form ATP (hence phosphorylation). This stage of the aerobic system occurs on the cristae (infoldings on the membrane of the mitochondria). The NADH+ from glycolysis and the Krebs cycle, and the FADH+ from the Krebs cycle pass down electron carriers which are at decreasing energy levels, in which energy is released to reform ATP.electronshydrogen ions

Each NADH+ that passes down this electron transport chain provides enough energy for 3 molecules of ATP and each molecule, and each molecule of FADH+ provides enough energy for 2 molecules of ATP. If you do your math this means that 10 total NADH+ molecules allow the rejuvenation of 30 ATP, and 2 FADH+ molecules allow for 4 ATP molecules to be rejuvenated (The total being 34 from oxidative phosphorylation, plus the 4 from the previous 2 stages meaning a total of 38 ATP being produced during the aerobic system). The NADH+ and FADH+ get oxidized to allow the NAD and FAD to return to be used in the aerobic system again, and electrons and hydrogen ions are accepted by oxygen to produce water, a harmless by-product.phosphorylation

The byproducts of most catabolic processes are NADH and [FADH 2 ] which are the reduced forms. Metabolic processes use NADH and [FADH 2 ] to transport electrons in the form of hydride ions (H - ). These electrons are passed from NADH or [FADH 2 ] to membrane bound electron carriers which are then passed on to other electron carriers until they are finally given to oxygen resulting in the production of water. As electrons are passed from one electron carrier to another hydrogen ions are transported into the intermembrane space at three specific points in the chain. The transportation of hydrogen ions creates a greater concentration of hydrogen ions in the intermembrane space than in the matrix which can then be used to drive ATP Synthase and produce ATP (a high energy molecule).

The coenzyme component of the dehydrogenase(usually the niacin-containing nicotinamide adenine dinucleotide [NAD]) accepts pairs of electrons (energy) from hydrogen. Although the substrate oxidizes and gives up hydrogens (electrons), NAD gains hydrogen and two electrons and reduces to NADH; the other hydrogen appears as H in the cell fluid. The riboflavin-containing coenzyme,flavin adenine dinucleotide (FAD) serves as another electron acceptor to oxidize food fragments. Like NAD, FAD catalyzes dehydrogenation and accepts electron pairs. Unlike NAD, FAD becomes FADH2 by accepting both hydrogens. NADH and FADH2 provide energy-rich molecules because they carry electrons with high energy-transfer potential.

The cytochromes, a series of iron-protein electron carriers dispersed on the inner membranes of the mitochondrion, then pass (in “bucket brigade” fashion) pairs of electrons carried by NADH and FADH2. The iron portion of each cytochrome exists in either its oxidized (ferric or Fe3) or reduced (ferrous, or Fe2) ionic state. By accepting an electron, the ferric portion of a specific cytochrome reduces to its ferrous form. In turn, ferrous iron donates its electron to the next cytochrome and so on down the line. By shuttling between these two iron forms, the cytochromes transfer electrons to ultimately reduce oxygen to form water. NAD and FAD then recycle for subsequent electron transfer. The NADH generated during glycolysis (see p. 145) converts back to NAD via “shuttling” of the hydrogens from NADH across the mitochondrial membrane.

Electron transport by specific carrier molecules constitutes the respiratory (or cytochrome) chain, the final common pathway where electrons extracted from hydrogen pass to oxygen. For each pair of hydrogen atoms, two electrons flow down the chain and reduce one atom of oxygen to form one water molecule. During the passage of electrons down the five-cytochrome chain, enough energy releases to rephosphorylate ADP to ATP at three of the sites. Only at the last cytochrome site, cytochrome oxidase (cytochrome aa3, with strong affinity for oxygen), discharges its electron directly to oxygen.

the route for hydrogen oxidation, electron transport, and energy transfer in the respiratory chain that releases free energy in relatively small amounts. In several of the electron transfers, the formation of high-energy phosphate bonds conserves energy. Each electron acceptor in the respiratory chain has a progressively greater affinity for electrons. In biochemical terms, this affinity for electrons represents a substance’s reduction potential. Oxygen, the last electron receiver in the transport chain, possesses the largest reduction potential. Thus, mitochondrial oxygen ultimately drives the respiratory chain and other catabolic reactions that require continual availability of NAD and FAD.

Oxidative Phosphorylation Oxidative phosphorylation synthesizes ATP by transferring electrons from NADH and FADH2 to oxygen.

Most ATP is produced in the electron transport system

Anaerobic breakdown of glucose results in the net production of only 2 ATP, while aerobic metabolism nets 38 ATP

The net chemical reaction of the aerobic metabolism of glucose C 6 H 12 O 6 + 6O ADP + 38P  6CO 2 + 6H ATP

Comparison of the power and capacity of the various energy production systems The ATP-PC system has low capacity because there is a limited store of phosphagens available. Carbohydrate oxidation is limited by glycogen depletion. Fatty acid metabolism has the greatest capacity because, under normal conditions, each person has an inexhaustible supply of energy-rich fats.