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Exercise Physiology Exam 1Bioenergetics - Chapters 5-7, 8 (pp 186-190; RER), lab and lecture notes1. Differentiate between aerobic and anaerobic metabolism- This refers to the two “systems” that the body uses to make energy or ATP. Aerobic respirationmeans “with oxygen” and anaerobic means “without oxygen, but those terms aren’t technicallycorrect. ATP production starts with glycolysis in the cell’s cytosol. The six carbon molecule is cleavedover many steps into two three carbon molecules, called pyruvate. This is known as anaerobicrespiration, since oxygen is nowhere in the equation. At this point, the pyruvate can formlactate to keep glycolysis running if ATP is needed fast (during intense exercise) or it can enterthe 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 thanglycolysis 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 weneed energy right away. Aerobic is commonly called “slow glycolysis” since it takes a long time toutilized, but provides much more energy. 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 poweryour muscles. ATP is an adenosine molecule (one of the bases of DNA) attached to threephosphates. When one phosphate is cleaved, energy is released during the cleavage. One thingyou will notice is everything in the body is controlled via adding a phosphate to something ortaking 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. Tony Berardi Page 13. Describe glycolysis. Know net ATP yield depending on substrate used (glycogen or glucose), andknow what other energetic molecules are formed (e.g. NADH + H+)? How is lactate formedduring 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 (capitalized because it’s probably important). 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.  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 thatglycolysis forms. When you need energy fast, this glycolysis has to keep running, but the cell willrun out of NAD fast. When pyruvate forms lactate, NADH (only makes all it’s ATP in the electron Tony Berardi Page 2transport chain) will turn back into NAD. This will allow glycolysis to keep happening, and thus form the 2 ATP. 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, known as the powerhouse of the cell, it has committed to aerobic respiration. Once inside, it will form acetyl-coA, along with a NADH; this is irreversible. As acetyl-coA, it will go through many reactions, which release CO2 (this is what we exhale) and they will also form NADH and FADH2, along with a GTP.  Each cycle of the Krebs cyle or TCA cycle, form 3 NADH, 1 FADH2, and one GTP. The formation ofpyruvate to actely-coA forms 1 NADH. So if we add it all up, we have formed 4 NADH, 1 FADH2, and 1 GTP, but remember that we have two pyruvates, so we double everything to give 8 NADH,2 FADH, and 2 GTP. All these molecules will makes since after the next step. 5. Describe the ETC. Know what the role of NADH + H+ and FADH+ in the ETS and the differences in energy yield. Know the general mechanism by which energy is produced in the ETS.- The next stop for all those NADH and FADH2 is the electron transport chain; the GTP forms an ATP through a different reaction. A simple understanding is all that is needed. There are four complexes that make up the chain, and each complex takes away electrons from the NADH and FADH. The very last complex takes all the electrons and uses them to form an ATP molecule. Oxygen is the final electron acceptor, and this is why we need to breathe oxygen to live. 


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