12 Exercise Physiology Exam 1 Bioenergetics Chapters 5 7 8 pp 186 190 RER lab and lecture notes 1 Differentiate between aerobic and anaerobic metabolism This refers to the two systems that the body uses to make energy or ATP Aerobic respiration means with oxygen and anaerobic means without oxygen but those terms aren t technically correct ATP production starts with glycolysis in the cell s cytosol The six carbon molecule is cleaved over many steps into two three carbon molecules called pyruvate This is known as anaerobic respiration since oxygen is nowhere in the equation At this point the pyruvate can form lactate to keep glycolysis running if ATP is needed fast during intense exercise or it can enter the cell s mitochondria Once it enters the mitochondria it is committed to aerobic respiration and it is known as such This process is very lengthy but produces much more energy than glycolysis alone Oxygen is the final electron receptor for this A better term for anaerobic is fast glycolysis since it supplies energy fast and is used when we need energy right away Aerobic is commonly called slow glycolysis since it takes a long time to utilized but provides much more energy Additional Information Covering the Energy Systems The body has three different sources of energy that it can pull from and they all depend on the INTENSITY of the activity or another way to think about it is how fast do you need the energy o You have a system called the ATP Pcr system and this occurs in the cytosol of the cell The cytosol is the outer area where glycolysis occurs and it in charge of supplying energy for explosive activities We have ATP chilling in the cell available for immediate breakdown and during intense activity the body will cleave this ATP to ADP to get that phosphate to generate muscle contraction Normally this process of splitting the ATP would deplete your stores very quickly in about 3 seconds thus the body has a Tony Berardi FLASHNOTES 12 molecule called phospo creatine floating around With all the ADP dancing around the cytosol the PCr will donate its phosphate to reform an ATP and thus you can prolong the ATP breakdown You will have an explosive force production for a grand total of 10 15 seconds Wooohooo What exercises depend on the ATP Pcr system Think explosive Polevaulting jumps sprints throwing if you need energy extremely fast then this is the system for you o Then you have glycolysis which I go into more detail later on in the guide and that will be fore middle distance events say an 800m sprint o Then beta oxidation And remember this yields the most ATP 2 What is ATP How does it function How is it formed This is the main energy currency in the body Think of ATP as money that can be used to power your muscles ATP is an adenosine molecule one of the bases of DNA attached to three phosphates When one phosphate is cleaved energy is released during the cleavage One thing you will notice is everything in the body is controlled via adding a phosphate to something or taking a phosphate off So the body takes chemical energy in the form of ATP and transforms it into mechanical energy in the form of muscle contraction 3 Describe glycolysis Know net ATP yield depending on substrate used glycogen or glucose and know what other energetic molecules are formed e g NADH H How is lactate formed during glycolysis What are the conditions under which it is formed This is the catabolic pathway that glucose enters to yield energy Just know that you start with glucose go through a whole bunch of reactions and end up with pyruvate Pyruvate can then go to two paths that I will explain later This process occurs in the cells cytosol Anaerobically glucose will become lactate Anaerobic mean without oxygen Aerobically it will become acetyl Coa Glycolysis only occurs in the cell s cytosol Through many steps the net ATP is only 2 If you want to learn all the steps two steps at the beginning actually use 1 ATP each so you have to put in an input to get an output of ATP After you put in 2 ATP you then make 4 ATP in the next steps but you only end up with a net of 2 ATP Tony Berardi FLASHNOTES 12 Glycogen is the storage form of glucose in the body the muscles combine many glucose molecules together as storage Free glucose is also circulating in your blood The difference in the maximum amount of ATP formed between them is based on the first step of glycolysis In the first step glucose is phosphorylated into glucose 6 phosphate and this takes one ATP This is so the glucose does not leave the cell Free glucose must take this step so the glucose does not leave the cell Since glycogen is already in the muscle the glucose simply has to break its storage and thus it will skip that step free glucose takes What does this mean That the total amount of ATP formed from glycogen will always be one more than free glucose So glycolysis will form 3 ATP if glycogen is used The potential for glucose metabolism to form ATP is in the form of the high energy molecules NADH2 and FADH2 These molecules carry electrons from hydrogen atoms and this electrons are what creates the majority of ATP in aerobic respiration in the electron transport chain So glycolysis takes the six carbon glucose and cleaves it into two three carbon pyruvates Now what Depending on how fast our muscles need ATP will determine what happens now If we need energy fast as in during intense exercise pyruvate will form lactate The reason for this is simple to form pyruvate the body had to use a NAD to form NADH has a lot of potential to form ATP so this means that NAD is required in order to form pyruvate and form the 2 ATP that glycolysis forms When you need energy fast this glycolysis has to keep running but the cell will run out of NAD fast When pyruvate forms lactate NADH only makes all its ATP in the electron transport chain will turn back into NAD This will allow glycolysis to keep happening and thus form the 2 ATP So lactate is formed when we run out of NAD because the cycle is moving so fast Lactate formation regenerates NAD so we can form more pyruvate and more lactate if we need more NAD 4 Describe the krebs cycle Know what happens to pyruvate before entering the Krebs cycle Know what important high energy molecules are formed e g FADH NADH H ATP Now if energy is not required right away as in endurance exercise the pyruvates will enter another route Instead of forming lactate they will enter the cell s mitochondria Once it enters the mitochondria
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