3/6/12

ATP - Alotta Tricky Poop - Study of Adenosine Triphosphate

Hi there people in the knowledge world. This blog will focus on the micro level of what goes down in our bodies during exercise. I’m doing this because (1) It’s somewhat important to know what’s happening when we burn out or break down and (2) This will help me study for one of my many tests this week.
I’m nice so I’ll put the applicable stuff first: (1) Food is stored as ATP as glycogen. The more stored glycogen we have, the more instant energy we have. (2) High intensity exercise results in more rapid glycogen depletion. However, if total work is the same the same amount of glycogen depletion will be equal. High intensity exercise results in greater increase in Plasma epinephrine which is a powerful stimulator of glycogenolysis. (3) When we enter into Krebs that means that carbs, fat, or protein was burnt to do! CALORIES! We enter Krebs cycle during exercise by doing Aerobic exercise.
What is Fatigue (army clothes!!): -Let’s start with ATP (Adenosine triphosphate)- Sustaining human life depends on continual replenishment of ATP. Increasing metabolic rate (exercise) requires increase in ATP resynthesis. Food we take in is stored as immediate energy in the form of ATP. Fatigue is not related to ATP depletion as once thought but actually is related to THE RATE OF ATP RESYNTHESIS! We fatigue when the breakdown of ATP (hydrolysis) is greater than the rate of resynthesis. There are 4 major sites of ATP breakdown (hydrolysis) during muscular work: Cross bridge cycle (actomyosin interaction); SR Ca ++ pumps; Sarcolemma Na+/K+ pumps; and Neuronal membrane Na+/K+ pumps.
-Now onto ATP resynthesis (because this tells us how we can defeat fatigue): There are several ways glucose can be synthesized: Glycolysis is the breakdown of glucose (anaerobic); Glycogenesis is the process by which glycogen is synthesized from glucose to be stored in the liver; Glycogenolysys is the process by which glycogen is broken into glucose – 1- phosphate to be used by muscles; Gluconeogenesis is the production of glucose from non carbohydrate sources. Glycolosis – Glucose + 2Pi + 2ADP + 2NAD => 2 pyruvate + 2 ATP + 2 NADH + 2 H+ + 2H2O; inhibitors are 6-phosphofructokinase and pyruvate kinase (ie. They slow it down).
Glycogenolysis – breakdown of glucose: Epinephrine is a whole body effect, Cisternae of sarcoplasmic reticulum is a local response only. Epinephrine -> B receptor -> cyclic AMP -> Phosphorylase b -> phosphorylase a -> Glycogen ->Glucose! Cisternae of sarcoplasmic reticulum -> Ca+ Calmodulin -> Phosphorylase b ->…. APPLICABLE TO WORKOUT: High intensity exercise results in more rapid glycogen depletion. However, if total work is the same the same amount of glycogen depletion will be equal. High intensity exercise results in greater increase in Plasma epinephrine which is a powerful stimulator of glycogenolysis. We have the good ‘ol Phosphagen System: This reaction uses the enzyme creatine phosphokinase or CPK; ADP + CP => ATP +C. This only supports a few seconds of intense exercise; we can think power lifting or especially Olympic lifting. Myokinase System: This reaction uses the enzyme myokinase (adenylate kinase) ADP +ADP => ATP + AMP (BTW a buildup of AMP can make our processes go in reverse… not good) Fast Myosin containing cells convert excess AMP into ammonia, AMP +H20 => IMP + NH3; Slow Myosin uses inorganic phosphate to solve the problem AMP + Pi => Adenosine + PPi. -Full ATP resynthesis during exercise (what is going on deep deeeeeep down inside yo body)
Oxidative (Aerobic metabolic pathway system) The oxidative pathway consists of two parts, both of with are found inside the mitochondria. Krebs cycle – The primary purpose of the Krebs cycle is to breakdown the compound acetyl-CoA and make the compounds NADH and FADH. Acetyl CoA is made by breaking down carbohydrates, lipids, or proteins. ( when we enter into Krebs that means that either carbs, fat, or protein was burnt to do! CALORIES) Because NADH cannot pass the Mitochondrial membrane(not fat solluable) it uses an H+ to become Dihydroxyacetone Phosphate (DHAP), it crosses the membrane, gives the H+ to FAD making it FADH to produce 1-2 ATP. This process is less efficient because it costs us 2 ATP (this is in Fast twitch muscles). Fun point, NADH yields 5 ATP from krebs while it only yields 3 from Glycolysis. Each turn of the Krebs cycle produces 3 NADH and 1 FADH which equals 10 ATP. The Malate-aspartate shuttle occurs in slow twitch muscles; NADH stays NADH but is transferred into Malate, looses an H+ and then becomes OAA (Oxeloacytate). FUN GRAPH:

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BS, MS - exercise Physiology
EPC - Board Certified Exercise Physiologist

Published Thesis
The impact of three different forms of warm up on performance


The Effects of Glucose Supplementation on Barbell Velocity and Fatiguability in Weightlifting - A pilot study"

Graduate from Midwestern State University, founder of Endunamoo Barbell Club, and Endunamoo Strength and Conditioning. Working to help athletes physically reach their goals and achieve scholarships while spiritually pouring into as many people as possible on all platforms.