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24 Cards in this Set
- Front
- Back
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energy
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ability to perform work
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bioenergetics
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# flow of energy in a biological system
* conversion of food into usable energy |
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catabolism
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breakdown of large molecules into smaller ones associate with the release of energy
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anabolism
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synthesis of large molecule from small ones (using energy from catabolic reactions)
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exergonic reaction
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energy releasing reaction (generally catabolic)
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endergonic reaction
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require energy, include anabolic processes and the contraction of muscle
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metabolism
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total of all catabolic/exergonic and anabolic/endergonic reactions in a biological system
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ATP
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Adenosine triphosphate
-allows transfer of energy from exergonic to endergonic reactions |
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Phosphagen system
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anaerobic, occurs in absense of oxygen
* provides ATP for the short term, high intensity activity * active at start of all exercises * Myosin ATPase catalyzes the hydrolysis of ATP to ADP + P o creatine kinase catalyzes the creation of ATP from ADP and creatine phosphate * fast energy * Myokinase reaction - 2 ADP molecules interact with Myokinase and an ATP and AMP are created o AMP stimulus of glycolysis |
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glycolysis
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* breakdown of carbs (glycogen from muscle or glucose from blood) to make ATP
* high intensity muscular activity |
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fast glycolysis
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* Fast Glycolysis
o occurs with reduced oxygen availability o pyruvate is converted to lactic acid providing ATP o results in end product of lactic acid + also hydrogen ion buildup + interfers with glycolitic reactions and muscle excitation-contraction coupling + results in decrease in in available energy # Fatigue o lactic acid converted to salt - lactate + not fatigue producing + normally .5-2.2 mmol/L of blood and.5 - 2.2mmol/kilo of wet muscle o blood lactate levels reflect lactic acid buildup and clearance + clearance is a return to homeostasis - ability to recover # can be done by oxidiagtion # or transported in blood to other muscle fibers to be oxidized * also can be moved in blood to liver and converted to glucose o Cori cycle Reaction for fast glycolysis Glucose + 2Pi + 2ADP ---> 2Lactate + 2ATP + H2O |
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slow glycolysis
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* if there is oxygen in the mitochondria the product of glycolysis (pyruvate) is not turned to lactic acid but transported to mitochondria, along with 2 NADH (nicotinamid adenine dinucleotide) which were produced during glycolysis
* when pyruvate enters the mitochondria it is turned to Acetyl CoA o happen by pyruvate byhydrogenase complex * Acetyl CoA can enter krebs cycle for more ATP production * NADH enters electron transport chain to pruduce more ATP reaction for slow glycolysis glucose + 2Pi + 2ADP + 2NAD ---> 2Pyruvate + 2ATP + 2NADH + 2H2O |
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energy yield of glycolysis
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* produces net of 2 ATP from 1 glucose
o if glycogen (storage form of glucose) then 3 ATP produced + happens as result of phosphorylation (adding a phosphate to glucose) being skipped |
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How is glycolysis controlled?
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* stimulated by intense activity by ADP
o Inorg. P, ammonia, decrease in pH and AMP o low pH from lack of O2 and high ATP inhibits it + creatine phosphate, citrate, free fatty acids * rate limiting step o slowest reaction in a series + in glycolysis - conversion of fructose-6-phosphate to fructose-1,6-biphosphate # catalyzed by phosphofrutokinase (PFK) * AMP from Phosphagen system (myokinase react.) stimulates PFK * also ammonia fron deamina-tion (removing amino grop from amino acid) |
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lactate threshold
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ex. intensity at which lactate begins an abrupt increase above baseline
* around 50-60% of max O2 uptake in untrained 70-80% in trained |
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OBLA
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2nd increase at higher relative intensities
# onset of blood lactate accumultion # concentrations neainr 4 mm0l/L blood * happens during more muscle recruitment o type II - suited for aanaerobic - lactic acid producing -training near or above LT and OBLA push both to the right (increase the baseline) |
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oxidative system
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aerobic
* Primary source of ATP at rest and during low-intensity activities o uses primaily carbs and fats as substrates o at rest 70% of ATP derived from fat - 30% from carbs + after onset of exercise, switch to preference for carbs # during high-intensity aerobic exercise almost 100% of energy from carbs * however, during prolonged sub-max, steady work, shift back to fats and protein |
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Glucose and Glycogen Oxidation
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# oxidative metab. of blood glucose and muscle glycogen begins with glycolysis
* if O2 present, end product of glycolysis, pyruvate, is not converted to lactic acid o pyruvate then trasported to mitochondria and enters Krebs cycle |
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krebs cycle
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# reactions that continue oxidation of substrate begun in glycolysis - produces 2 ATP from GTP (guinine triphosphate) for each glucose
* from each glucose, 6 NADH and 2 FADH2 (flavin adenine dinucleotide) o molecule transport Hydrogen to ETC (electron transport chain) + Produce ATP from ADP ----> rephosphorylation # uses NADH and FADH2 + H atoms passed down chain # using cytochromes - electron carriers + forms a proton gradient - provides energy for ATP production # O2 serves as final electron acceptor (H20 as product) o NADH and FADH2 enter ETC at different times - differ in ATP production + NADH makes 3 ATP + FADH2 makes 2 ATP o production of ATP during axidation called Oxidative Phosphorylation + 1 glucose molecule make 38 ATP with Oxidative system |
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Fat oxidation
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# Triglcerides broke down for energy by Lipase
* relase fatty acids in blood * free fatty acides enter mitochondria and undergo beta oxidation o Acetyl CoA and H atoms is product + Acetyl CoA enter krebs directly + H taken by NADH and FADH2 to ETC |
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protein oxidation
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* Not a significant source of energy
* can be broken down into its costituent amino acids o then converted to glucose, pyruvate, or other krebs intermediate products * during long term activity used more for energy * mostly bcaa that are used in oxidation o leucine, isoleucine, valine o waste products of amino acids eleminated through urea and amonia |
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how is oxidation controlled?
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* rate limiting step
o conversion of isocitrate to alpha-ketogluterate + stimulated by catalyst isocitrate dehydrogenase, which is stimulated by ADP o reactions that produce NADH and FADH2 + if not enough NAD+ and FAD2+ then krebs slowed |
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energy substrates
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# molecules that provide starting materials for bioenergetics reactions
* can be depleted during exercise o phosphagens and glycogen usually |
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glycogen de/repletion
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* 300-400 g in whole of muscle and 70-100g in liver
o anaerobic training can increase resting glycogen stores * rate of depletion related to ex. intensity o muscle glyc. more important than liver glyc. during moderat-high intensity o liver more important during lower intensity * Repletion o .7 - 3.0 g of carbs/kg of body weight every 2 hrs o aids in glycogen repletion |
