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Presentation1

  1. 1. Chemical Bonding PowerPoint By: Sarah Goldberg http://repairstemcell.files.wordpress.com/2009/02/blood-doping1.jpg
  2. 2. What is hemoglobin? <ul><li>Hemoglobin (also spelled hemoglobin and abbreviated Hb or Hgb) is the iron-containing oxygen-transport metalloprotein in the red blood cells of vertebrates, and the tissues of some invertebrates. </li></ul><ul><li>A type of protein in the red blood cells that carries oxygen to the tissues of the body. </li></ul><ul><li>A red blood cell protein responsible for transporting oxygen in the bloodstream. Also provides the red coloring of blood. </li></ul><ul><li>The oxygen carrying pigment of the red blood cells (erythrocytes). It is a conjugated protein containing four heme groups and globin. A molecule of hemoglobin contains 4 globin polypeptide chains - designated alpha, beta, gamma and delta. In the adult, Hemoglobin A predominates (alpha2, beta2). </li></ul>http://repairstemcell.files.wordpress.com/2009/02/blood-doping1.jpg search?hl=en&client=safari&rls=en&defl=en&q=define:hemoglobin&ei=RFhmS_qxEITSNc__pe4G&
  3. 3. How is hemoglobin important in the transport if oxygen in our bodies? <ul><li>Hemoglobin is a metalloprotein (a protein that contains a metal) which is very important in oxygen transport. Hemoglobin has four parts (subunits) toit, each with an iron atom bound. Each iron atom can be oxidized by bindinga molecule of oxygen, and each time this happens the protein changes shapeso that it can bind more oxygen molecules more effectively, this is known ascooperativity. </li></ul><ul><li>If the hemoglobin is an environment that is low in oxygen it won't bind much oxygen, but as a result of cooperatively if the hemoglobin is around a lot of oxygen it will bind the oxygen very well. This way hemoglobin is used by the body to take oxygen from the lungs (where there is a lot of it) to places like our muscles (which are low in oxygen). </li></ul>http://repairstemcell.files.wordpress.com/2009/02/blood-doping1.jpg search?hl=en&client=safari&rls=en&defl=en&q=define:hemoglobin&ei=RFhmS_qxEITSNc__pe4G&sa=X&oi
  4. 4. How is the transport of oxygen by hemoglobin a real-life example of chemical bonding ? <ul><li>Allostery is a property not limited to enzymes. The basic principles of allostery are also well illustrated by the oxygen-transport protein hemoglobin. The binding of oxygen to hemoglobin isolated from red blood cells displays marked sigmoid behavior (similar to that observed for the activity of ATCase, as a function of substrate concentration), which is indicative of cooperation between subunits. </li></ul><ul><li>What is the physiological significance of the cooperative binding of oxygen by hemoglobin? Oxygen must be transported in the blood from the lungs, where the partial pressure of oxygen ( pO 2 ) is relatively high (approximately 100 torr), to the tissues, where the partial pressure of oxygen is much lower (typically 20 torr). Let us consider how the cooperative behavior represented by the sigmoidal curve leads to efficient oxygen transport. In the lungs, hemoglobin becomes nearly saturated with oxygen such that 98% of the oxygen-binding sites are occupied. </li></ul>http://repairstemcell.files.wordpress.com/2009/02/blood-doping1.jpg http://www.newton.dep.anl.gov/askasci/mole00/mole00765.htm
  5. 5. How is the hemoglobin related to a successful clime to the top of Mt. Everest? <ul><li>This Java applet provides a simple simulation of a climb up Mt. Everest and the body’s response to the decrease in atmospheric oxygen. At sea level, the air pressure is 760 torr and the atmo- sphere consists of 21% oxygen. This corresponds to a partial pressure of about 160 torr of oxygen. By the time the air gets into your lungs and mixes with the air left from the last breath, the partial pressure of oxygen is about 100 torr. At the top of Mt. Everest, the amount of available oxygen has dropped by 50% to about 50 torr. </li></ul><ul><li>If a person has spent their entire life at sea level and is then suddenly transported to the top of Mt. Everest, the decrease in atmospheric oxygen will almost certainly cause a medical condition known as hypoxia. This will lead to severe disorientation and possibly death. Hypoxia may have contributed to the Everest tragedy in May of 1996, which claimed the lives of 8 climbers. </li></ul>http://repairstemcell.files.wordpress.com/2009/02/blood-doping1.jpg http://www.newton.dep.anl.gov/askasci/mole00/mole00765.htm
  6. 6. What does PH have to do with the transport of oxygen by hemoglobin? <ul><li>The pressure of oxygen in the lungs is 90–95 torr; in the interior tissues it is about 40 torr. Therefore, only a portion of the oxygen carried by the red blood cells is normally unloaded in the tissues. However, vigorous activity can lower the oxygen pressure in skeletal muscles below 40 torr, which causes a large increase in the amount of oxygen released. This effect is enhanced by the high concentration of carbon dioxide in the muscles and the resulting lower pH (7.2). The lower carbon dioxide concentration (and hence higher pH) at the lungs promotes the binding of oxygen to hemoglobin and hence the uptake of oxygen. </li></ul><ul><li>Temperature changes also influence the binding of oxygen to hemoglobin. In the relative warmth of the interior organs, the curve is shifted to the right (like the curve for pH 7.2), helping to unload oxygen. In the relative coolness of the lungs, the curve is shifted to the left, aiding the uptake of oxygen. </li></ul>http://repairstemcell.files.wordpress.com/2009/02/blood-doping1.jpg http://www.newton.dep.anl.gov/askasci/mole00/mole00765.htm
  7. 7. What is blood doping? <ul><li>Both types of transfusion can be dangerous because of the risk of infection and the potential toxicity of improperly stored blood. Homologous transfusions present the additional risks of communication of infectious diseases and the possibility of a transfusion reaction. From a logistical standpoint, either type of transfusion requires the athlete to surreptitiously transport frozen RBCs, thaw and re-infuse them in a non-clinical setting and then dispose of the medical paraphernalia. </li></ul><ul><li>A more modern approach, which has been applied to blood doping with mixed success, is to test the blood or urine of an athlete for evidence of a banned substance or practice, usually EPO. This approach requires a well-documented chain of custody of the sample and a test method that can be relied upon to be accurate and reproducible. Athletes have, in many cases, claimed that the sample taken from them was misidentified, improperly stored or inadequately tested. </li></ul>http://repairstemcell.files.wordpress.com/2009/02/blood-doping1.jpg http://www.newton.dep.anl.gov/askasci/mole00/mole00765.htm
  8. 8. What is the difference between autologous and homologous blood doping? <ul><li>Currently, two methods of transfusion are being used in blood doping: Homologous and Autologous. The former, homologous is the transfusion of blood from a donor, other than oneself. This form leaves the individual open for possible disease due to infected blood, and the consequences of being caught. Since the blood is donated, minute differences in cells can be detected in tests (such as those given to athletes before competitions). The upside, however, is that the performance of the athlete never falters since they are not the donators of the blood. </li></ul><ul><li>In contrast, autologous blood doping is the use of one's own banked blood for transfusion. This causes a period in which the athlete is not in top shape, however, it eliminates the risk for infected blood. Additionally, it is harder to detect those who have used this method since tests have to look for different ques of doping instead of differences in blood cells, as is used in homologous doping tests. </li></ul>http://repairstemcell.files.wordpress.com/2009/02/blood-doping1.jpg http://www.newton.dep.anl.gov/askasci/mole00/mole00765.htm
  9. 9. What is EPO and why is it used? <ul><li>Pharmacological cheating in sports is not a new phenomenon. Unfortunately, the modern era has witnessed explosive growth in new and different ways to achieve false victory. Advances in biochemistry, medicine, and other fields have benefited humanity in countless ways. Sadly, however, some have abused these advances for, “pursuit of victory at all cost”. A recent article by Dr. Timothy Noakes (1) highlights the breadth and depth of the problem. He discusses several “cheating venues”, but for this article I wish to focus on one, erythropoietin. </li></ul><ul><li>Erythropoietin is a relatively recent entry into the deceitful pursuit of glory. EPO is a protein hormone produced by the kidney. After being released into the blood stream it binds with receptors in the bone marrow, where it stimulates the production of red blood cells (erythrocytes). Medically, EPO is used to treat certain forms of anemia (e.g., due to chronic kidney failure). Logically, since EPO accelerates erythrocyte production it also increases oxygen carrying capacity. This fact did not long escape notice of the athletic community. </li></ul>http://repairstemcell.files.wordpress.com/2009/02/blood-doping1.jpg http://www.newton.dep.anl.gov/askasci/mole00/mole00765.htm
  10. 10. What are the medical uses of blood doping? <ul><li>Hemoglobin is a metalloprotein (a protein that contains a metal) which is very important in oxygen transport. Hemoglobin has four parts (subunits) toit, each with an iron atom bound. Each iron atom can be oxidized by bindinga molecule of oxygen, and each time this happens the protein changes shapeso that it can bind more oxygen molecules more effectively, this is known ascooperativity. </li></ul><ul><li>If the hemoglobin is an environment that is low in oxygen it won't bind much oxygen, but as a result of cooperatively if the hemoglobin is around a lot of oxygen it will bind the oxygen very well. This way hemoglobin is used by the body to take oxygen from the lungs (where there is </li></ul>http://repairstemcell.files.wordpress.com/2009/02/blood-doping1.jpg http://www.newton.dep.anl.gov/askasci/mole00/mole00765.htm
  11. 11. Why is blood doping used in sport? <ul><li>Allostery is a property not limited to enzymes. The basic principles of allostery are also well illustrated by the oxygen-transport protein hemoglobin. The binding of oxygen to hemoglobin isolated from red blood cells displays marked sigmoid behavior (similar to that observed for the activity of ATCase, as a function of substrate concentration), which is indicative of cooperation between subunits. </li></ul><ul><li>What is the physiological significance of the cooperative binding of oxygen by hemoglobin? Oxygen must be transported in the blood from the lungs, where the partial pressure of oxygen ( pO 2 ) is relatively high (approximately 100 torr), to the tissues, where the partial pressure of oxygen is much lower (typically 20 torr). Let us consider how the cooperative behavior represented by the sigmoidal curve leads to efficient oxygen transport. In the lungs, hemoglobin becomes nearly saturated with oxygen such that 98% of the oxygen-binding sites are occupied. </li></ul>http://repairstemcell.files.wordpress.com/2009/02/blood-doping1.jpg http://www.newton.dep.anl.gov/askasci/mole00/mole00765.htm
  12. 12. Provide one documented example of blood doping used in sport. <ul><li>Athletes don't re-inject blood very much anymore. Instead, cheating athletes will inject genetically engineered drugs which cause the body to create extra red blood cells. The most common type of blood doping chemical used is called EPO - which is used to treat patients who have kidney disease. The one supposedly used by those scamming skiers in Salt Lake City is called darbepoetin. </li></ul><ul><li>Blood doping is cheating and has several unhealthy side effects. Injecting blood doping chemicals can cause kidney damage, jaundice (the skin, eyes and body fluids turn yellow) and blood clots. Re-injecting blood from an athlete's own body can cause blood infections and heart problems. </li></ul>http://repairstemcell.files.wordpress.com/2009/02/blood-doping1.jpg http://www.newton.dep.anl.gov/askasci/mole00/mole00765.htm
  13. 13. Provide a second documented example of blood doping in sport . <ul><li>Athletes who use blood doping to increase their performance will have a higher red blood cell density. This can be detected by testing the athlete's levels of hemoglobin (protein which causes blood to be the red color we see.) EPO and other blood doping drugs can be detected in an athlete's system by urine tests. It's believed there are some blood doping drugs out there that drug testers don't know about which some athletes are using. </li></ul><ul><li>Blood doping is a method of increasing the number of red blood cells in the body which in turn carry more oxygen to red blood cells. </li></ul>http://repairstemcell.files.wordpress.com/2009/02/blood-doping1.jpg http://www.newton.dep.anl.gov/askasci/mole00/mole00765.htm
  14. 14. What are the side affects of blood doping? <ul><li>Blood doping is cheating and has several unhealthy side effects. Injecting blood doping chemicals can cause kidney damage, jaundice (the skin, eyes and body fluids turn yellow) and blood clots. Re-injecting blood from an athlete's own body can cause blood infections and heart problems. </li></ul><ul><li>Athletes who use blood doping to increase their performance will have a higher red blood cell density. This can be detected by testing the athlete's levels of hemoglobin (protein which causes blood to be the red color we see.) EPO and other blood doping drugs can be detected in an athlete's system by urine tests. It's believed there are some blood doping drugs out there that drug testers don't know about which some athletes are using. </li></ul>http://repairstemcell.files.wordpress.com/2009/02/blood-doping1.jpg http://www.newton.dep.anl.gov/askasci/mole00/mole00765.htm

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