Clicker Question

1. Clicker Question • Monosaccharide sugars and amino acids first enter the blood stream at the: • capillaries in the small intestine • capillaries in the stomach • left atrium • right atrium • capillaries in the salivary glands

3. Where are we? • Last time I discussed: • The circulatory system and the transport of oxygen, glucose and other nutrients throughout the body. • Heart attacks, strokes and pulmonary embolisms. • The heart and lungs. • Speaking of hearts and lungs, • We sang together (with Chloe): “How do you measure, a year in the life?” • Today we will cover: • Cellular respiration and the biosynthesis of molecules.

4. With a Little Help from My Friends • Take a couple minutes to meet or get to know a little better the people sitting around you. • Make sure that nobody is left out. • Study through living. Study nutrition, digestion, etc. together over lunch or dinner! Town of Bethel, New York Joe Cocker With a Little Help from My Friends Woodstock 1969 Bethel Woods Center for the Arts With a Little Help from My Friends with Clapton, Page and Beck

5. Cells Differ Because the Specifics of a Cell Depend on Its Functional Specialization • Each cell has the basic organelles of a eukaryotic cell. However, the proportion and position of each organelle depends on the cell type. • Each cell has the basic chemicals required for life, however, the precursors required by each cell, the rate of turnover of the chemicals, and the chemicals produced by each cell differ depending on cell type. • The structure and chemical composition of a cell depends on the function of the cell in an organ.

6. However Almost All Cells Require Glucose and Oxygen to Make ATP • Every cell “burns” glucoseas an energy source to synthesize ATP from ADP and Pi. • Each cell also uses the carbon skeleton of glucose to synthesize chemicals that are necessary for that cell. • The majority of cells burn glucose completely during cellular respiration. • The complete combustion of glucose requires oxygen. Aerobic respiration results in about 38 ATP/glucose. • Some fast twitch muscle cells burn glucose quickly but incompletely in the absence of oxygen. This anaerobic respiration results in only 2 ATP/glucose.

7. Heat Chemical reactions Carbon dioxide + Glucose + ATP ATP water Oxygen Energy for cellular work Figure 5.2B Aerobic Energy transformations in a cell From the aorta Burning: The combination of oxygen with a reduced carbon source which yields carbon dioxide, water and heat.

8. 0 O2 Breathing CO2 Lungs O2 CO2 Bloodstream Muscle cells carrying out Cellular Respiration Glucose + O2 CO2 +H2O +ATP Figure 6.2 We must breathe so that the cells of our body get oxygen and eliminate carbon dioxide

9. First Law of Thermodynamics • Energy cannot be created or destroyed. • That is, our bodies require energy for the organs to do their work and we get that energy by eating food.

10. We Need to Eat Approximately 1600 Calories/Day Just to Maintain the Body • Various activities use up additional Calories (=kcal). McDonalds Burger King Wendy's

11. Putting the Number and Distribution of Calories in Perspective clintonbushhaitifund.org www.redcross.org www.unicef.org/

12. If you eat a Quarter Pounder with Cheese, a medium French Fries and drink a medium Classic Coke, you take in 1110 Calories. • These are enough Calories to allow you to run 7 minute miles for about 1.4 hours. • If you don’t run for 1.4 hours (or do an equivalent amount of work), you will store the Calories as 123 g of fat (about ¼ of a pound) since fat has a fuel value of 9 Calories/gram.

13. There Are Other Ways to Burn Calories

14. Fat is Good • Fat is a very efficient form of energy storage since 1 gram of fat can store 9 Calories, whereas 1 gram of carbohydrate or 1 gram of protein can only store 4 Calories. • If we stored energy as carbohydrate or as protein, we would weigh more than we do.

15. Fat is a Light Way to Store Calories • ~ 2000 Calories can be stored by ~½ pound of fat in our body. • (2000 Calories) (1 g fat/9 Calories)(2.2 pounds/1000 g) = 0.49 pounds of fat • ~ 2000 Calories would be stored as ~ 1 pound of protein or ~ 1 pound of carbohydrate in our body. • (2000 Calories) (1 g protein or carbohydrate/4 Calories)(2.2 pounds/1000 g) = 1.1 pounds of protein or carbohydrate

16. Although Storing too Many Calories as Fat (BMI >30) is Unhealthy

17. Skeletal Muscle Cells Burn (Oxidize) Calories When We Do Work • The food (glucose) is oxidized (loss of electrons and their accompanying protons) by oxygen to form carbon dioxide, water and available energy (ATP). • The oxygen is reduced (gain of electrons and their accompanying protons) to form water. • The ATP formed is used for muscle contraction.

18. Food is Oxidized by a Class of Enzymes Called Dehydrogenases • The dehydrogenases work by transferring the electrons and their accompanying protons to NAD to make NADH.

19. ATP is then Formed By a Controlled Oxidation of NADH by an Electron Transport Chain • The burning of wood is an uncontrolled release of energy in the form of heat. • By passing electrons stepwise though the electron transport chain, the energy of NADH can be conserved in ATP molecules with a minimal loss as heat.

20. The Controlled Burning of Food For Energy Occurs in the Cytoplasm (Glycolysis) and the Mitochondrion (Krebs Cycle and ElectronTransport Chain)

21. As the Electrons Travel from NADH to Oxygen through Various Acceptors of the Electron Transport Chain, They Pull Protons Across a Membrane and Form an Electrical Battery that can Make ATP

22. Respiratory Poisons, Including Cyanide and Carbon Monoxide, Inhibit Electron Transport and Prevent ATP Formation

23. The Carbohydrates, Fats and Proteins Enter the Respiratory Pathway in Various Places to Make ATP • This is a miracle. Imagine a car engine that could run on gas, butter, peanuts and hay.

24. Perhaps One Day a Car will be able to Run on All Wastes

25. Many Molecules in Cells are Synthesized from Intermediates Formed During Respiration • Some of the food molecules are incompletely oxidized and are transformedinto other molecules. • The ATP is used to do muscular workand to put together carbon skeletons in the biosynthesis of macromolecules.

26. The Discovery of Cellular Respiration • That is cellular respiration and biosynthesis in a nutshell. • How were these miraculous processes discovered? • It all started with Robert Boyle (1662) and his vacuum pump.

27. Robert Boyle Accidentally Discovered that Air Is Necessary for Life • Robert Boyle was conducting experiments to see whether butterflies could fly in air made thin by his newly invented vacuum pump. • When he pulled a vacuum in the bell jar, in which they were flying, the butterflies fell down and died. • Did they die as a consequence of the fall or did they become weak because they needed air?

28. Robert Boyle Accidentally Discovered that Air Is Necessary for Life • Boyle realized that the air was necessary for life after he repeated his experiments using a lark with a broken wing. Since the lark could not fly, any adverse effects of the lack of air on the lark in the bell jar would not be caused by falling but would indicate the necessity of air for life. • The lark died in the vacuum, showing that air is necessary for life.

30. Mice also Need Air to Live • By putting a mouse in a bell jar and removing the air with a vacuum, Boyle showed that air was also a necessity for mice. • But his critics suggested that the animals might have died from being in an uncomfortable place, claustrophobia or the lack of food.

31. Robert Boyle Performed Controls to Convince Critics • In response to his critics, Boyle put a mouse in the bell jar overnight, gave it a paper bed and plenty of cheese and then placed the bell jar by the fireside to keep the mouse warm during the night.

32. Robert Boyle Performs Controls to Convince Critics • In the morning, Boyle observed that the mouse was very much alive. • However, as soon as Boyle evacuated the air, the mouse started to die, showing that lack of air, and not the lack of “creature comforts” was necessary for life.

33. Air is Taken Up By The Lungs • Robert Hooke (1726), an assistant of Boyle’s and all around genius, showed that the air was taken up by the lungs by demonstrating that a dog whose diaphragm was not working could be kept alive if air was continuously blown with a bellows through the lungs, but not through other parts of the body.

34. Oxygen is the Vital Part of the Air • Joseph Priestley (1774) furthered the work of Boyle and Hooke when he showed that animals took up the part of the air that was necessary for a candle to burn. • Thus oxygen was the vital part of the air that was taken up by the respiration of animals.

35. Carl Djerassi and Roald Hoffmann

36. Antoine Lavoisier Showed that the Combustion of Food during Respiration is Chemically Like the Burning of Wood • Also in the 1770s, Antoine Lavoisier, the founder of modern chemistry, determined that combustion results from the combination of oxygen with carbon and hydrogen. • Lavoisier believed that respiration and combustion were analogous reactions. • Lavoisier used analogy to discover new phenomena.

37. “In respiration, as in combustion, it is the atmospheric air which furnished oxygen…; but since in respiration it is…the blood, which furnishes the combustion matter, if animals did not regularly replace by means of food…that which they lose by respiration, the lamp would soon lack oil, and the animal would perish as a lamp is extinguished when it lacks nourishment.”

38. “The proofs of this identity of effects in respiration and combustion are immediately deducible from experiment. Indeed, upon leaving the lung, the air that has been used for respiration no longer contains the same amount of oxygen; it contains not only carbonic acid gas but also much more water than it contained before it had been inspired.”

39. Formula for Combustion and Respiration • C(H2O) + O2 CO2 + H2O + heat • Respiration was defined as a combustion process and measured by the uptake of O2 and the expulsion of CO2 and H2O. • Using a melting ice calorimeter, Lavoisier and Pierre Simon de Laplace found that for equal outputs of CO2, approximately the same amount of ice was melted by the respiration of a guinea pig and the burning of charcoal. • Lavoisier believed that the heat provided the energy necessary for the processes we associate with life.

40. Political Correctness and Science • Like Priestley, Lavoisier never finished his experiments on respiration because he was “politically incorrect”. • Lavoisier, who was a tax collector, lost his head in a guillotine during the French Revolution.

41. Lectures on Respiration for Children faraday

42. (Almost) All Cells Respire • Scientists disagreed as to where the conversion of O2 to CO2 took place. Was it the lungs or was it the blood? • This was a false dichotomy. The conversion occurred in both places, as well as in (almost) every other part of the organism, as Lazzaro Spallanzani (1803) showed when he isolated various tissues and demonstrated that all tissues were capable of consuming O2 and giving off CO2. Measure oxygen uptake (↑) or carbon dioxide evolution (↓).

43. The Crucial Secret…Respiration is a Cellular Process Common to All Cells • Many biologists still did not believe that respiration occurred outside the blood. Eduard Pflüger (1872) removed the blood of a frog and replaced it with saline and found that this frog respired just like a normal frog. He also mentioned that insects and plants that have no blood respire too. Pflüger concluded, "Here lies, and I want to state this once and for all, the crucial secret of the regulation of the total oxygen consumption by the organism, a gravity which is entirely determined by the cell itself....“

44. The Scientific Method: A Critical Attitude is Clearly Required… • According to Thomas Gold (1989), “New ideas in science are not always right just because they are new. Nor are the old ideas always wrong just because they are old. A critical attitude is clearly required of every scientist….. Whenever the established ideas are accepted uncritically, but conflicting new evidence is brushed aside and not reported because it does not fit, then that particular science is in deep trouble—and it has happened quite often in the historical past.”

45. Be Aware of Cow Dung • Conventional • Wisdom • of • the • Dominant • Group

46. Always Be Skeptical: Even Babe Ruth Only Got it Right at Bat 34% of the Time Babe Ruth’s Lifetime Batting Average: 0.342

47. The Mitochondrion is the Organelle Involved in Respiration • By the end of the nineteenth century, it became clear that respiration was a cellular process that took place in almost each and every cell. • Soon after, centrifugation showed that the uptake of oxygen was associated with particles and subsequent structural studies showed that the mitochondrion was the respiratory organelle. • Mitos is Greek for thread, and chondrin is Greek for small grain.

48. The German Dye Industry

49. Mitochondria Can Be Stained With Fabric Dyes • At the suggestion of Paul Ehrlich, Leonor Michaelis (1900) tested the ability of the various newly-invented fabric dyes to stain living tissue. • Michaelis showed that the mitochondria in pancreatic exocrine cells could be selectively and vitally stained with a dilute solution of one of these dyes, Janus green.

50. Staining is only transient because the mitochondria reduce the dye and render it colorless. The ability of mitochondria to oxidize and reduce various dyes was what led Kingbury (1912) to propose that the mitochondria may be involved in cellular respiration.