Exercise Physiology
Terms
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- Oxidative phosphorylation:
- The phosphorylation of ATP coupled to the respiratory chain.
- Kinetic energy:
- Refers to a chemical reaction that consumes energy.
- Glycogenolysis:
- The breaking down, or catabolism, of the polysaccharide glycogen into molecules of the sugar glucose and molecules of glucose 1-phosphate within the body by enzymes. The enzymes are controlled by nerve impulses and hormones.
- Fermentation:
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The anaerobic enzymatic conversion of organic compounds, especially carbohydrates, to simpler compounds, especially to ethyl alcohol, resulting in energy in the form of adenosine triphosphate (ATP).
The process is used in the production of alcohol, bread, vinegar and other food or industrial products. It differs from respiration in that organic substances rather than molecular oxygen are used as electron acceptors.
Fermentation occurs widely in bacteria and yeasts, the process usually being identified by the product formed, for example, acetic, alcoholic, butyric and lactic fermentation are those that result in the formation of acetic acid, alcohol, butyric acid and lactic acid, respectively. - Matrix:
- Ground substance in which things are embedded or that fills a space (as for example the space within the mitochondrion). most common usage is for a loose meshwork within which cells are embedded (e.g. Extracellular matrix), although it may also be used of filters or absorbent material.
- Acetyl-CoA:
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Condensation product of coenzyme A and acetic acid, symbolized as CoAS~COCH3; intermediate in transfer of two-carbon fragment, notably in its entrance into the tricarboxylic acid cycle and in fatty acid synthesis.
This coenzyme plays a huge role in intermediary metabolism, in which cells synthesize, break down or use nutrient molecules for energy production, growth, etc.
Acetyl-coenzyme A synthase is found in bacteria and plants and catalyses the reaction in which acetate enters metabolic pathways and forms acetyl-coenzyme A. - Beta oxidation:
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The oxidative breakdown of fatty acids into acetyl-coenzyme A by repeated oxidation at the beta-carbon atom.
Oxidation of the beta-carbon (carbon 3) of a fatty acid causes the formation of the beta-keto (beta-oxo) acid analog. This is of importance in fatty acid catabolism, the entire pathway for the catabolism of saturated fatty acids containing an even number of carbon atoms. Beta-oxidation is a part of this pathway and acetyl-CoA is a major product of this pathway. - Anabolism:
- Synthesis, opposite of catabolism.
- Gluconeogenesis:
- Synthesis of glucose from non carbohydrate precursors, such as pyruvate, amino acids and glycerol. Takes place largely in liver and serves to maintain blood glucose under conditions of starvation or intense exercise.
- Deamination:
- The process through which enzymes strip amino groups off biomolecules.
- Lactate dehydrogenase (LDH):
- An enzyme with 5 forms: LDH-1 is in the heart, its blood level can rise when heart muscle is damaged. Other forms can be found in the liver, brain, kidney, skeletal muscle and bone. A useful blood test in the evaluation of many disease processes, including heart attack, liver disease, muscular dystrophy and bone disease.
- Glycolysis:
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The conversion of a monosaccharide (generally glucose) to pyruvate via the glycolytic pathway (i.e. The Embden Meyerhof Parnas pathway) in the cytosol.
Generates ATP without consuming oxygen and is thus anaerobic. - Krebs cycle:
- Tricarboxylic acid cycle or citric acid cycle.
- Free energy:
- A thermodynamic term used to describe the energy that may be extracted from a system at constant temperature and pressure. In biological systems the most important relationship is: _G = RTln(Keq), where Keq is an equilibrium constant.
- Anaerobic:
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1. Lacking molecular oxygen.
2. Growing, living or occurring in the absence of molecular oxygen, pertaining to an anaerobe. - Oxidation:
- The process whereby fatty acids are degraded in steps, losing 2 carbons as (acetyl) CoA. Involves CoA ester formation, desaturation, hydroxylation and oxidation before each cleavage.
- Pyruvate:
- Pyruvate is the final product of glycolysis. You get two molecules of pyruvate for every molecule of glucose that goes through glycolysis.
- Endergonic reaction:
- Refers to a chemical reaction that consumes energy.
- Bioenergetics:
- A scientific field that deals with the application of thermo dynamic principles to organisms and biological systems.
- ATP?adenosine triphosphate:
- A nucleotide present in all living cells which serves as an energy source for many metabolic processes and is required for ribonucleic acid synthesis.
- Lactic acid:
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A byproduct of carbohydrate metabolism (anaerobic metabolism). A lactic acid level may be measured in the bloodstream in conditions of metabolic acidosis.
Lactic acid is an intermediate product of carbohydrate metabolism and is derived mainly from muscle cells and red blood cells.
Exercise will normally raise lactic acid levels. Conditions of oxygen deprivation (for example shock, heart failure, lung disease) will trigger anaerobic metabolism within muscle tissue resulting in lactic acid build up in the tissues.
Normal lactic acid levels are 4.5 to 19.8 mg/dl. - Energy:
- Typically defined as the ability to do work. Power is the rate at which work is done, or the rate at which energy is changed. Work characterizes the degree to which the properties of a substance are transformed. Energy exists in many forms, which can be converted from one to another in various
- Intermembrane space:
- Region between the two membranes of mitochondria and chloroplasts. On the endosymbiont hypothesis, this space would represent the original phagosome.
- Denatured:
- Made unnatural or changed from the normal in any of its characteristics; often applied to proteins or nucleic acids heated or otherwise treated to the point where tertiary structural characteristics are altered.
- Cytochrome:
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Any electron transfer haemoprotein having a mode of action in which the transfer of a single electron is effected by a reversible valence change of the central iron atom of the haem prosthetic group between the +2 and +3 oxidation states.
Classified as cytochromes a in which the haem contains a formyl side chain, cytochromes b, which contain protohaem or a closely similar haem that is not covalently bound to the protein, cytochromes C in which protohaem or other haem is covalently bound to the protein and cytochromes d in which the iron tetrapyrrole has fewer conjugated double bonds than the haems have. Well known cytochromes have been numbered consecutively within groups and are designated by subscripts (beginning with no subscript), for example cytochromes C, c1, C2,. New cytochromes are named according to the wavelength in nanometres of the absorption maximum of the a band of the iron (II) form in pyridine, for example, C 555. - Chemiosmosis:
- A theoretical mechanism (proposed by Mitchell) to explain energy transduction in the mitochondrion. As a general mechanism it is the coupling of one enzyme catalysed reaction to another using the transmembrane flow of an intermediate species. For example Cytochrome oxidase pumps protons across the mitochondrial inner membrane and ATP synthesis is driven by re entry of protons through the ATP synthesizing protein complex. The alternative model is production of a chemical intermediate species, but no compound capable of coupling these reactions has ever been identified.
- Aerobic:
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1. <chemistry> Having molecular oxygen present.
2. <microbiology> Growing, living or occurring in the presence of molecular oxygen. Bacteria that require oxygen to survive (aerobic bacteria). The used of aerobic microbes to break down raw sewage (aerobic waste treatment).
3. <physiology> Requiring oxygen for respiration. - Activation energy:
- The amount of energy (expressed in joules) that is needed to convert all the molecules in one mole of a reacting substance from a ground state to the transition state
- Outer membrane:
- The larger of the two membranes of a double membrane.
- Exergonic reaction:
- Describes a chemical reaction that releases energy in the form of heat, light, etc.
- Cori cycle:
- The phases in the metabolism of carbohydrate: 1) glycogenolysis in the liver; 2) passage of glucose into the circulation; 3) deposition of glucose in the muscles as glycogen; 4) glycogenolysis during muscular activity and conversion to lactate, which is converted to glycogen in the liver.
- NAD+:
- Nicotinamide adenine dinucleotide (oxidised form).
- Energy of activation:
- Energy that must be added to that already possessed by a molecule or molecules in order to initiate a reaction; usually expressed in the Arrhenius equation relating a rate constant to absolute temperature.
- ADP?adenosine diphosphate:
- ADP is used as an adenine, a ribose and a diphosphate unit.
- Cellular respiration:
- The conversion within the cell of nutrients (such as sugar molecules) into chemical energy in the form of ATP, by reacting the food with oxygen (O2) until the food has completely been degraded into carbon dioxide and H2O.
- Chemical Energy:
- Energy liberated or absorbed by a chemical reaction, e.g., oxidation of carbon, or absorbed in the formation of a chemical compound.
- Glycogen:
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Branched polymer of D glucose (mostly _(1-4) linked, but some _(1-6) at branch points).
Size range very variable, up to 10exp5 glucose units. Major short term storage polymer of animal cells and is particularly abundant in the liver and to a lesser extent in muscle. In the electron microscope glycogen has a characteristic asterisk or star appearance. - Vitamin:
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An essential low molecular weight organic compound required in trace amounts for normal growth and metabolic processes. They usually serve as components of coenzyme systems.
For humans Vitamin A, the B series, C, D1 and D2, E and K are required. Deficiencies of one or more vitamins in the nutrient supply result in deficiency diseases. - Substrate-level phosphorylation:
- Synthesis of high-energy phosphate bonds through reaction of inorganic phosphate with an activated (usually) organic substrate.
- ATP synthase:
- An enzyme that catalyses the conversion of phosphate and ADP into ATP during oxidativephosphorylation in mitochondria and bacteria or photophosphorylationin chloroplasts.
- Inner membrane:
- The smaller of a double membrane.
- Enzyme:
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A protein molecule produced by living organisms that catalyses chemical reactions of other substances without itself being destroyed or altered upon completion of the reactions.
Enzymes are classified according to the recommendations of the Nomenclature Committee of the International Union of Biochemistry. Each enzyme is assigned a recommended name and an Enzyme Commission (EC) number.
They are divided into six main groups, oxidoreductases, transferases, hydrolases, lyases, isomerases and ligases.
- Entropy:
- The amount of disorder in a system.
- Cofactor:
- Inorganic complement of an enzyme reaction, usually a metal ions.
- Coenzyme:
- An organic nonprotein molecule, frequently a phosphorylated derivative of a water soluble vitamin, that binds with the protein molecule (apoenzyme) to form the active enzyme (holoenzyme).
- Reactant:
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A substance taking part in a chemical reaction.
Acute phase reactants, A group of proteins that are produced and/or released in increased concentrations during the acute phase reaction, including fibrinogen; C-reactive protein; complement proteins B, C3, C4; a2-acid glycoprotein, serum amyloid A, proteinase inhibitors, etc. - Substrate:
- A substance upon which an enzyme acts.
- Active Site:
- A specific region of an enzyme where a substrate binds and catalysis takes place (binding site).
- Metabolism:
- The sum of all the physical and chemical processes by which living organized substance is produced and maintained (anabolism) and also the transformation by which energy is made available for the uses of the organism (catabolism).
- Coupled Reactions:
- Two chemical reactions that share a common intermediate (for example, the product of the first reaction is a reactant in the second) and therefore have some kind of energy exchange between them.