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Make mcq quiz with 4 option in which one is correct -'10 Basis of Material Science • .....;;;";;;"~~;;,,;;,,,,;.;.,,;;,,,;,,;.;,.,------------ 6. Temporary materials: Some materials are meant to be placed in the oral cavity for a short period of time for different reasons. • Temporary crowns: While a permanent crown is prepared in the dental laboratory, the patient must wait for few days before it can be fabricated and cemented into place. Does patient experience any problems during this time period? If the tooth is vital (the pulp is alive), the patient is likely to experience pain and sensitivity while eating and drinking, also it looks unesthetic. What can be done to solve this problem? A temporary crown is placed before the patient leaves the clinic. It is constructed and luted in the same appointment in which the crown preparation is done. Temporary crowns are not very strong or esthetic but they serve adequately till the permanent crown is ready to be cemented. • Temporary restorations: Sometimes it is difficult to decide immediately the best line of treatment for a particular tooth. The exact condition of the pulp may not be obvious to the dentist from the patient's symptoms. A dentist removes all or part of the decay and then places a temporary restoration to have time to observe the behaviour of the pulp or to give the pilip time to heal before deciding the further treatment required. Classification based on Location of Fabrication 4,9 Materials can be classified based on the location of fabrication into: • Direct restorative materials. • Indirect restorative materials Direct restorative materials: They include those materials which are used to restore cavity preparations directly in the oral cavity (Box 1.5). Box 1.5: Examples of direct restorative materials Amalgam, composites, glass ionomer and other materials, which set by chemical reactions in the mouth. Indirect restorative materials: It includes those restorations which must be fabricated outside the mouth, indirectly on a cast/ model/ die, because their processing condition would harm oral tissues. Materials used in the construction of such prosthesis are called indirect restorative materials (Box 1.6). Box 1.6: Examples of indirect restorative materials Gold inlays, crowns of metal, ceramic and polymers, which are processed at elevated temperatures. Some indirect composite restorations can be processed under specific wavelength of light, e.g. Ceramage. Classification based on Longevity of Use 1. Permanent restorations: These restorations are not planned to be replaced for a particular time period. Though they are referred to as permanent, actually they are not, e.g. fillings, crowns, bridges and dentures do not last forever (Fig. 1.5). 2. Temporary restorations: These restorations are planned to be replaced in a short period of time, such as few days to weeks. For ~ Permanent C/) c c -.2 0 c- :;::; Cll co Interim ~ Q; 0 .8ll::1iJ C/) o~ Cll a:: c:=:J Temporary Time period Fig. 1.5: Diagram depicting the time period of use of a restoration. (Arrow in permanent restoration depicts that such restorations are not planned to be replaced for a long period of time.) Introducton to Dental Materials Dental materials Box 1.7: Characteristics of metals 1. High thermal and electrical conductivity 2. Ductility (pure metals are very soft and they can be bent without breaking) 3. Opacity (they do not transmit light) 4. Luster (they have a surface that strongly reflects light and appears bright and shiny) 5. They tend to dissolve to some extent in water or other aqueous solutions, producing cations. 6. All metals are white (actually gray) except for gold, which is yellow, and copper, which is reddish. 7. All metals are solid at room temperature except mercury, which is liquid at room temperature and is used with silver alloys as amalgam. 8. All metals have high melting temperatures because of high strength of the metallic bond that holds the atoms together. 3. Polymers 4. Composites Composites are mixtures of two or more of the first three classes in which the different components remain distinct from one another in the final structure. A common example is composite resin. Fig. 1.7a: Three-dimensional structure of iron (metal) Metals Metals are the oldest of the three classes of materials that have been used as dental materials. Metals are characterized by metallic bonds (Box 1.7) which will be discussed in the next chapter. Metals solidify with their atoms in a regular or crystalline arrangement (see Chapter 2), often in the form of a cube (Fig. 1.7a). example, temporary fillings done in a tooth during root canal treatment, which have to be replaced within 2-4 days during subsequent visits. They are used to protect the tooth and provide function till the final restoration is done. 3. Interim restoration: At times, dental treatment requires "long-term" definite temporary restorations or "interim" restorations. For examle, a 7-year-old child, met with trauma and fractured one of his central incisors. A large composite build- up may serve his immediate requirement until the root formation is completed and a permanent crown is placed. 5 Classification based on the Chemical Nature of the Material These are the atoms that make up a material and the way they are bonded together determine the properties of that materiaLS Weak bonds make for weak materials and vice versa (Table 1.4). Materials can be classified into different categories based on their primary atomic bonds (Fig. 1.6): 1. Metals 2. Ceramics Fig. 1.6: Classification of dental materials based on chemical nature 12 Basis of Material Science Box 1.9: Benefits of ceramics in dentistry 1. Many ceramic oxides are used as pigmenting agents. These oxides produce good range of colors. Due to this characteristic, we are able to match almost any tooth color with good esthetic results. 2. They are inert, i.e. not chemically reactive. This quality provides ceramics with good bio- compatibility. 3. Ceramic materials are translucent, like natural teeth. This translucency gives the ceramic crown a more natural appearance than any other dental material. Fig. 1.7b: Internal arrangement of tetrahedral structure of ceramic (silica) four large oxygen atoms surround smaller silicon atom Ceramics A ceramic is a compound formed by the union of a metallic and a non-metallic element (Box 1.8). Most of these materials are oxides, formed by the union of oxygen with metals such as silicon, aluminum, calcium and magnesium (Fig.1.7b). Ceramics may be simple or complex. Examples of simple ceramics are alumina and silica. Examples of complex ceramics are feldspar (potassium aluminum silicate) and kaolin (hydrated aluminum silicate). Ceramics may be crystalline or non- crystalline (i.e. amorphous). Porcelain is a specific type of ceramic used extensively in dentistry (Box 1.9). Box 1.8: Characteristics of ceramics 1. High melting points. 2. Brittleness, which means they cannot be bent or deformed (no sliding) to any extent without actually cracking and breaking. 3. They are poor conductor of heat and electricity. 4. They are chemically inert. 5. They have excellent esthetic result in terms of matching natural teeth. Fig. 1.8: Stucture of synthetic polymer Polymers They are the latest addition (early to mid- 1900s) to dental materials. Most of the polymers are nowadays synthesized by humans. Polymers are giant, long-chain organic molecules (Fig. 1.8). Polymers are characterized by covalent bonds within each molecule, giving them tremendous strength in a single direction. Try to break a nylon rope by pulling it! They are poor conductors of heat and electri- city. Most polymers have a structure containing thousands of carbon atoms linked together like beads on a string. Others, such as silicone polymers are formed with silicon-oxygen bonds. Introducton to Dental Materials Table 1.4: Characteristics of different materials 13 Characteristics Bond Properties Crystal structure Metals Metallic bonding High strength and hardness, high electrical and thermal conductivity BCC, FCC, or HCP unit cells Ceramics Ionic or covalent bonding, or both High hardness and stiffness, electrically insulating, refractory, and chemically inert Crystalline or amorphous Polymers Covalent bonding Low sensitivity, high electrical resistivity, and low thermal conductivity, strength and stiffness vary widely Amorphous and crystalline Composites Composites are combinations of any of the basic ceramic, metallic and polymeric materials (Box 1.10). Each material that makes up composites is called a phase. Their properties tend to be somewhere between those of their basic constituents and are used to enhance their performance, longevity and handling chracterstics. Box 1.10: Types of composites in dentistry 1. Ceramic - metallic composite: Tungsten carbide bur. 2. Metal - polymer composite: Die materials in dental laboratory. 3. Ceramic - polymer composite: Enamel, dentin, bone and restorative composites. A composite is a kind of "combination" of materials, which compliment each other. The properties lacking in one material are compensated by those of the other material. For example, restorative composite has two phases, namely resin and fillers. Teeth and bones are examples of natural composites. Enamel is a composite of hydroxyapatite (which is a ceramic material) and protein (which is a polymer). EVALUATION OF DENTAL MATERIALS Most manufacturers of dental materials maintain a quality assurance programme (As per international standard like ADA specifications) and materials are thoroughly tested before being released into the market for dental practitioner (Fig. 1.9). Laboratory Evaluations Most ADA/ ANSI specifications involve laboratory tests. The tests performed as per these specifications are useful but they all are performed in vitro, (carried out in the laboratory away from the clinical conditions) which have a lot of limitations in clinical practice.lO Clinical Notes 1. For example, most of the direct restorative materials are tested for their compressive strength but ultimately the material is subjected to a combination of compressive, tensile and shear stresses, which may decide the final success or failure of the material under masticatory load. 2. Similarly upper dentures mostly fracture along the midline because of bending. Hence a bending or transverse strength ~B-a-s-is-o-f-M-a-t-e-ria-I-S~c-ie-n-c-e-------------- ---------. test is far more meaningful for denture base materials than a compression test. Clinical Trials The majority of new materials are subjected to extensive clinical trials normally in co-operation with a dental college or hospital departments prior to their release. CONCLUSION As the number of available materials is going up, it is important that the dentist remains more aware about new products so that their judgement about the selection of material remains successful. Materials which have not been thoroughly evaluated should be avoided, specially with clinical dentistry falling under Consumer Protection Act (CPA). I Research and development I iI Manufacturer/analysis Ideal requirements for clinical use: Thermal, optical, mechanical, chemical, biological Available materials and their properties are evaluated Launch of new I product Choice and selection of material by the dentist Critical assessment based on clinical performance I I H feedback to I
Vocabulary b1 cefr level, fill in the gap sentences with the words:enable found implement restore agenda agriculture commander backpacking consulate continuity cooperation departure destination duration embassy funding immigrant shelter support mission. for example: the meaning of the word implement in Hebrew is: . a. b. c. d.
In a small town, the local TV station was at the center of a **scandal**. A critical news report about the mayor had been mistakenly **broadcast**, leading to widespread **disruption** in the community. People were filled with **anxiety** as they waited for the station to **schedule** a retraction. The station's new manager had to **familiarize** herself quickly with the situation to **tackle** the fallout. She decided to **tailor** a special segment to address the viewers' concerns directly. The pressure was **overwhelming**, but she knew it was the only way to restore trust and calm the chaos.
Here are 12 questions based on the Word Wall Spin the Wheel Activity focusing on Robber Barons and Labor Unions: Multiple Choice: What is a "Trust"? A) A labor organization formed by skilled workers. B) A large business combination that aims to control markets and reduce competition. C) A worker strike that demands higher wages. D) A type of factory producing steel. Answer: B Which labor union sought to include all workers, regardless of skill, gender, or race? A) American Federation of Labor (AFL) B) Industrial Workers of the World (IWW) C) Knights of Labor D) Pullman Company Answer: C Who was the founder of Standard Oil, known for his monopolistic practices? A) Andrew Carnegie B) Eugene V. Debs C) John D. Rockefeller D) Samuel Gompers Answer: C Which event involved a nationwide railroad strike that led to federal intervention and the arrest of Eugene V. Debs? A) Haymarket Square Riot B) Pullman Strike C) Homestead Strike D) Coal Strike of 1902 Answer: B What is "Vertical Integration"? A) A system where one company controls all phases of production from raw materials to finished product. B) A labor union negotiation process for better working conditions. C) The consolidation of competing businesses under a single company. D) A strike where workers occupy a factory to prevent its operation. Answer: A Which of the following was a key goal of the American Federation of Labor (AFL)? A) Overthrow the capitalist system. B) Establish worker-run factories. C) Secure higher wages, shorter hours, and better working conditions. D) Eliminate all forms of skilled labor. Answer: C Fill in the Blank: John D. Rockefeller used ___________ to gain control over the oil industry and eliminate his competition. Answer: Trusts The labor organization founded by Samuel Gompers that focused on craft unionism and collective bargaining was the ___________. Answer: American Federation of Labor (AFL) The ___________ advocated for direct action and sought to organize all workers into one large union, regardless of skill or background. Answer: Industrial Workers of the World (IWW) The ___________ was an 1894 labor strike against the Pullman Company that resulted in federal troops being sent to restore order. Answer: Pullman Strike Andrew Carnegie’s belief that the wealthy had a moral obligation to use their wealth for the betterment of society was known as the ___________. Answer: Gospel of Wealth The ___________ began as a peaceful rally for an eight-hour workday but turned violent after a bomb was thrown, leading to a nationwide backlash against labor unions. Answer: Haymarket Square Riot These questions combine multiple choice and fill-in-the-blank formats, reinforcing key concepts related to labor unions and robber barons.
1. Battle of Lexington At the Battle of Lexington in 1775, British soldiers and colonial militia faced each other on the village green. A shot was fired, but no one knows for sure who fired first. Even so, this moment is often called the beginning of the American Revolution. Why is the Battle of Lexington still considered the start of the American Revolution, even though it is unclear who fired the first shot? A. It marked the first time colonists and British soldiers fought in open battle B. It proved that colonists planned the war long before the fighting began C. It showed that British soldiers were fully responsible for starting the war D. It confirmed that colonists had already declared independence from Britain 2. Battle of Concord After the fighting at Lexington, British troops marched to Concord to destroy colonial supplies. Instead, colonial militia gathered and fought back, forcing the British to retreat toward Boston. Why is the Battle of Concord considered an important turning point in the early American Revolution? A. It showed that colonial militias could organize and successfully push back British troops B. It proved that the British army had already lost control of all the colonies C. It confirmed that the colonies had officially declared independence from Britain D. It demonstrated that foreign countries were already helping the colonial forces 3. Second Continental Congress Much of the early violent conflict between colonists and British soldiers took place in Boston. After fighting broke out at Lexington and Concord near Boston, colonial leaders met at the Second Continental Congress in 1775 to decide what to do next. Which answer best describes the main actions taken by the Second Continental Congress? A. They created an army, chose a leader, and tried to avoid war with Britain B. They declared independence, wrote the Constitution, and ended the war C. They raised taxes, formed a monarchy, and supported British rule D. They ended slavery, gave women rights, and expanded voting laws 4. Olive Branch Petition In 1775, colonial leaders sent a letter called the Olive Branch Petition to King George III of Britain. Based on this situation, what was the main purpose of the Olive Branch Petition sent to the king? A. To ask the king to restore peace between both sides B. To declare independence from Britain and begin a new nation C. To request help from foreign countries in the war effort D. To organize protests against British taxes across the colonies 5. Battle of Bunker Hill On June 17, 1775, during the Battle of Bunker Hill in Boston, colonial forces fought against the British on a hill overlooking the city. The fighting was intense and led to heavy losses on both sides. Which statement best explains why the Battle of Bunker Hill was an important battle in the war? A. The colonists won the battle, showing they were stronger than British forces B. The colonists won the battle, showing the British that the war would be short and easy for the colonists C. The British won the battle, showing the war would be difficult and costly for both sides D. The British won the battle, showing British forces could defeat the colonists easily 6. Pamphlets During the American Revolution, pamphlets were short printed writings that were inexpensive to produce and often written in everyday language so many colonists could read them. How did these features of pamphlets most affect their role in the American Revolution? A. They helped spread ideas widely, allowing more colonists to form and share opinions B. They limited ideas to educated leaders, keeping most colonists uninvolved C. They replaced newspapers entirely, becoming the only source of information D. They prevented disagreement, causing most colonists to think the same way 7. Thomas Paine’s Common Sense In 1776, Thomas Paine published Common Sense, a widely read piece of writing about the relationship between the colonies and Britain. How did this pamphlet most influence colonial thinking during the American Revolution? A. It encouraged colonists to support independence from Britain B. It convinced colonists to remain loyal to the British government C. It explained how colonial armies should organize attacks D. It described laws colonists were expected to follow 8. Declaration of Independence In July 1776, the Declaration of Independence listed complaints against King George III and explained the colonists’ ideas about government and rights. How do these parts of the Declaration of Independence work together to support the colonists’ decision? A. They connect ideas about rights to real examples, justifying separation from Britain B. They describe past events in detail, showing how the war had already ended C. They list future plans for government, explaining how leaders would be chosen D. They organize military actions, showing how the colonies planned to win 9. Washington Crosses the Delaware and Battle of Trenton In December 1776, George Washington led his army across the Delaware River and launched a surprise attack on Hessian mercenaries in Trenton. Which statement best explains why Washington’s crossing of the Delaware and the attack on Trenton was an important turning point in the war? A. It defeated British forces completely, ending the war in a short time B. It boosted morale, helping discouraged soldiers choose to keep fighting C. It brought foreign allies into the war, adding support for the colonies D. It led to independence, allowing the colonies to form a new nation 10. Battle of Saratoga In 1777, American forces defeated the British at the Battle of Saratoga, a major event during the American Revolution. Which statement best explains why the Battle of Saratoga was an important turning point in the war? A. It brought French support, helping Americans gain a strong advantage in the war B. It ended the war quickly, forcing Britain to surrender all control in the colonies C. It improved army training, helping soldiers become more skilled in future battles D. It changed leadership roles, causing new generals to take control of the army 11. Battle of Yorktown In 1781, American forces surrounded British troops at Yorktown, leading to a major moment in the American Revolution. Which statement best explains why the Battle of Yorktown was an important event in the war? A. French forces helped the Americans win, leading to the end of major fighting in the war B. Italian forces helped the British win, leading to a final victory over the American army C. German forces switched sides and helped the Americans win, leading to a final defeat for British troops D. French forces helped the British win, leading to a complete end of the war in the colonies 12. Treaty of Paris After the Battle of Yorktown, British public opinion turned against the war, and peace negotiations began. In 1783, American leaders signed the Treaty of Paris, which included agreements between the United States and Britain. Which statement best explains how the Treaty of Paris reflected the outcome of the American Revolution? A. Both sides made agreements, recognizing independence B. Americans gained independence, taking land without agreements C. British leaders kept control, ending the war with power D. Both sides refused compromise, continuing the war
LESSON 4. Cellular Respiration • Define cellular respiration • Identify the stages of clan respiration You have just learned how the energy from the sun is captured, processed, and stored in the form of glucose. Cellular respiration, another important life process, is the means by which cells release the stored energy in glucose to make adenosine triphosphate (ATP). The primary goal of this life process is to convert stored energy into usable form, such as ATP, for the cells to carry out their functions. Cellular respiration involves several chemical reactions. The reactions can be summed up in the following equation: C6 H12 O6 + 602 ----- 6 CO₂ +6H₂O + ATP Glucose oxygen carbon dioxide water energy Aerobic respiration reactions, or cellular respiration that takes place in the presence of oxygen, can be grouped into three stages glycolysis, Krebs cycle, and electron transport chain (ETC). Stage 1: Glycolysis Glycolysis is the process that breaks down one molecule of 6-C glucose into 3-C pyruvates or pyruvic acids. It also releases four molecules of ATP. This process occurs in the cytoplasm of the cell. The following is the step-by-step process of glycolysis. Take note that several enzymes are involved in this process. 1. The first step of glycolysis requires energy. It can only proceed when the two ATP molecules donate energy to the glucose by transferring a phosphate group with the help of an enzyme, producing glucose 6-phosphate 2. Then, a specific enzyme promotes the rearrangement of the atoms, producing the fructose 6-phosphate. 3. The action of the enzyme in step 2 promotes the transfer of a phosphate group from another ATP molecule, forming fructose 1,6-bisphosphate. 4. The resulting fructose 1,6-bisphosphate molecules, with the help of another enzyme, splits into two molecules, each with three carbon backbones. These two sugars are dihydroxyacetone phosphate and glyceraldehyde 3-phosphate. 5. Another important enzyme then rapidly interconverts the molecules of dihydro-xyacetone phosphate and glyceraldehyde 3-phosphate. This produces two molecules of glyceraldehyde 3-phosphate or 3-phosphoglyceraldehyde (PGAL) 6. The succeeding step involves another enzyme-mediated action. The hydrogen (H) from PGAL is transferred to the oxidizing agent, nicotinamide adenine dinucleotide (NAD), which forms NADH. A phosphate (P) is also added from the cytosol of the cell to oxidize the two molecules of PGAL, forming two 1.3-bisphosphoglycerate. 7. A phosphate (P) from 1,3-biphosphoglycerate is transferred to ADP to form ATP. This happens for each of the two 1,3-bisphosphoglycerate. resulting to a yield of two ATP and two 3-phosphoglycerate molecules. 8. A phosphate is transferred from 3-phosphoglycerate molecules from the third carbon to the second carbon, forming 2-phosphoglycerate molecules A hydrogen atom and a hydroxyl ((OH) group is released, which then combines to form water (H2O). The removal of H2O from 2-phosphoglycerate results in the formation of 2- phosphoglycerate molecules. 9. A hydrogen atom and a hydroxyl ((OH) group is released, which then combines to form water (H2O). The removal of H2O from 2-phosphoglycerate results in the formation of two phosphoenolpyruvic acid (PEP) 10. Phosphate (P) from PEP is transferred to ADP (and forms ATP) and the final product, pyruvic acid. This reaction yields two molecules of pyruvic acid and two ATP molecules In summary, a single glucose molecule that undergoes the process of glycolysis produces two molecules of pyruvic acid, four molecules of ATP, two molecules of NADEL and two molecules of H.O. However, only two molecules of ATP are counted as net products since two molecules of ATP are spent throughout the process. Stage II: Krebs Cycle The Krebs cycle, named after its proponent Sir Hans Adolf Krebs, is a cyclical series of enzyme-controlled reactions. This stage of cellular respiration occurs in the matrix of the mitochondria. It is sometimes. called the citric acid cycle (CAC) since it produces citric acid. Citric acid contains three carboxyl (COOH) groups; hence, it is also called the tricarboxylic acid cycle (TCA). This requires the pyruvic acids produced during glycolysis. The main function of this cycle is to produce high-energy-yielding molecules, namely, NADH and flavin adenine dinucleotide (FADH) that will later on be used in the electron transport chain reaction. Figure 6-7. Summary of glycolysis and corresponding products in each reaction presented (See Appendix F on page 285 for an enlarged and complete version of the image.) An initial process is needed for the Krebs cycle to begin. As a pyruvate molecule from glycolysis enters the mitochondrion, it undergoes an important preliminary ate to form acetyl-CoA reaction. Coenzyme-A (COA) combines with pyruvate help of an enzymatic complex. This conversion also produces CO, and NADH. The Krebs cycle is summarized as follows. Take note that several enzymes are involved in this process. 1. The Krebs cycle technically begins when the acetyl-CoA combines with oxaloacetic acid (OAA), a 4-C molecule, to produce citric acid, a 6-C molecule. 2. With the aid of an enzyme, the citric acid now goes through a series of reactions that releases energy. Water molecule is removed from the citric acid and is returned in a different location. The-OH group is repositioned, forming the molecule isocitrate. 3. Isocitrate is then oxidized, forming the a-ketoglutarate, a 5-C molecule. The byproducts of this reaction are NADH and CO, 4 The a-ketoglutarate loses its CO, and a coenzyme-A is added in its place. The decarboxylation occurs with the help of NAD, which then becomes NADH. The resulting molecule is called succinyl-CoA. 5. Succinyl-CoA is converted into succinate. Also in this reaction, a molecule of guanosine triphosphate (GTP) is synthesized. The GTP molecule has similar structure and energy properties to that of ATP and is used by cells the same way. The free phosphate group attacks the succinyl-CoA molecule, which detaches the COA. Then, phosphate is attached to GDP to come up with GTP, similar to the process that occur in ATP synthesis (from ADP to ATP). 6. Two hydrogens are removed from succinate, A molecule of flavin adenine dinucleotide (FAD), a coenzyme similar to NAD, is reduced to FADH, as it takes the hydrogens from the succinate. This reaction produces the fumarate. 7. Fumarate is then converted into malate as the addition of a water molecule is catalyzed. The final reaction is the regeneration of oxaloacetate. The resulting byproduct of this regeneration is NADH Recall that two pyruvate molecules were produced during glycolysis, causing the Krebs cycle to turn twice. Each tuts produces three molecules of NADH, single ATH one FADIH, and the by-product CO, which is exhaled. Stage III: Electron Transport Chain The electron transport chain (ETC) is a series of photon pumps on the inner membrane of the mitochondrion. Electron transport is the last stage of the cellular respiration. In this stage, the energy from NADH and FADH, from the Krebs cycle is transferred to ADP to produce ATP. This process is generally known as oxidative phosphorylation. This energy coupling mechanism in the cell was revealed by the work of Peter stored energy in the form of proton (1) gradient to phosphorylate (add phosphate) ADP and produce ATP. The pumping of hydrogen sons across the inner membrane creates higher concentration ions in the inner membrane than on the outside of the membrane. This chemiosmotic gradient causes the ions to flow back across the membrane where the concentration of ions is lower. ATP synthase lined in the matrix serve as a channel protein, helping the ions to move across the membrane. The chemiosmotic gradient powers the phosphorylation of ADP to ATP, which also occurs in the ATP synthase. After passing through the ETC, the oxygen, being the final hydrogen acceptor, combines with two electrons and two protons, forming a water molecule. Water is a by-product of cellular respiration and is excreted. MINI TEST 6-3 1. Which energy-releasing pathway yields the most ATF in each glucose molecule? 2. Briefly describe the two stages of aerobic respiration that follow glycolysis: (a) Krebs cycle (b) Electron transport chain Anaerobic Respiration Most cells carry out arrobic respiration when oxygen is present. Aerobic respiration is an efficient process that yields a lot of ATP. However, many organisms thrive in mud, marshes, animal gut, canned goods, sewage treatment pond, and deep oceans where oxygen is scarce. Organisms that can live without oxygen are called anaerobes. Cellular respiration that proceeds without the presence of oxygen is called anaerobic respiration. In the event that the oxygen supply becomes low, aerobic cells also perform fermentation and lactic acid fermentation anaerobic pathways. There are two common anaerobic pathways in these cells, alcoholic fermentation and lactic acid fermentation. In alcoholic fermentation, ethyl alcohol and carbon dioxide are produced by some cells using the pyruvate from glycolysis. Each pyruvate molecule is rearranged into acetaldehyde and carbon dioxide, which is eventually released. NADII gives up electrons to acetaldehyde to form ethanol Fermentation is widely used in the industry. Yeast, a fungus used in making bread. can undergo anaerobic respiration. Bakers aux sugar, flour, water, and yeast to form the bread dough. The dough rises due to the carbon dioxide and alcohol released by the yeast cells trapped in air bubbles. Beer and wine manufacturers, we yeast to ferment the sugars in wheat and grape juice, forming alcoholic beverages such as beer and wine. In some cells, glycolysis produces two pyruvates, two NADH molecules, and two ATP molecules. Pyruvate itself becomes the final acceptor of the electrons from the NADH that produces the final product: lactate. Oftentimes, this product is called lactic acid. Human skeletal muscles can carry out fermentation when the blood cannot supply the cells with adequate oxygen during strenuous activities. When lactic acid builds up in the muscles, fatigue, burning sensation, and cramps result. Lactic acid will continue to build up until there is adequate supply of oxygen. Lactic acid is then converted back into pyruvate in the liver. Muscles also restore normal functions. Have you ever wondered why milk or cream turns sour after some time? Bacterial cells that undergo fermentation are responsible in producing lactate that turns the milk sour. These bacteria are used in manufacturing yogurt and sour milk products. Fermentation pathways do not breakdown and utilize the glucose completely. ATP is no longer produced beyond the process of glycolysis. Thus, energy produced is just enough for some single-celled organisms, or the energy can only be used by multicellular organisms for a short period.
When it was his turn to speak, Adam Malik, Presidium Minister for Political Affairs and Minister for Foreign Affairs of Indonesia, recalled that about a year before, in Bangkok, at the conclusion of the peace talks between Indonesia and Malaysia, he had explored the idea of an organization such as ASEAN with his Malaysian and Thai counterparts. One of the “angry young men” in his country’s struggle for independence two decades earlier, Adam Malik was then 50 years old and one of a Presidium of five led by then General Soeharto that was steering Indonesia from the verge of economic and political chaos. He was the Presidium’s point man in Indonesia’s efforts to mend fences with its neighbors in the wake of an unfortunate policy of confrontation. During the past year, he said, the Ministers had all worked together toward the realization of the ASEAN idea, “making haste slowly, in order to build a new association for regional cooperation.” Adam Malik went on to describe Indonesia’s vision of a Southeast Asia developing into “a region which can stand on its own feet, strong enough to defend itself against any negative influence from outside the region.” Such a vision, he stressed, was not wishful thinking, if the countries of the region effectively cooperated with each other, considering their combined natural resources and manpower. He referred to differences of outlook among the member countries, but those differences, he said, would be overcome through a maximum of goodwill and understanding, faith and realism. Hard work, patience and perseverance, he added, would also be necessary. The countries of Southeast Asia should also be willing to take responsibility for whatever happens to them, according to Tun Abdul Razak, the Deputy Prime Minister of Malaysia, who spoke next. In his speech, he conjured a vision of an ASEAN that would include all the countries of Southeast Asia. Tun Abdul Razak was then concurrently his country’s Minister of Defence and Minister of National Development. It was a time when national survival was the overriding thrust of Malaysia’s relations with other nations and so as Minister of Defence, he was in charge of his country’s foreign affairs. He stressed that the countries of the region should recognize that unless they assumed their common responsibility to shape their own destiny and to prevent external intervention and interference, Southeast Asia would remain fraught with danger and tension. And unless they took decisive and collective action to prevent the eruption of intra-regional conflicts, the nations of Southeast Asia would remain susceptible to manipulation, one against another. “We the nations and peoples of Southeast Asia,” Tun Abdul Razak said, “must get together and form by ourselves a new perspective and a new framework for our region. It is important that individually and jointly we should create a deep awareness that we cannot survive for long as independent but isolated peoples unless we also think and act together and unless we prove by deeds that we belong to a family of Southeast Asian nations bound together by ties of friendship and goodwill and imbued with our own ideals and aspirations and determined to shape our own destiny”. He added that, “with the establishment of ASEAN, we have taken a firm and a bold step on that road”. For his part, S. Rajaratnam, a former Minister of Culture of multi-cultural Singapore who, at that time, served as its first Foreign Minister, noted that two decades of nationalist fervor had not fulfilled the expectations of the people of Southeast Asia for better living standards. If ASEAN would succeed, he said, then its members would have to marry national thinking with regional thinking. “We must now think at two levels,” Rajaratnam said. “We must think not only of our national interests but posit them against regional interests: that is a new way of thinking about our problems. And these are two different things and sometimes they can conflict. Secondly, we must also accept the fact, if we are really serious about it, that regional existence means painful adjustments to those practices and thinking in our respective countries. We must make these painful and difficult adjustments. If we are not going to do that, then regionalism remains a utopia.” S. Rajaratnam expressed the fear, however, that ASEAN would be misunderstood. “We are not against anything”, he said, “not against anybody”. And here he used a term that would have an ominous ring even today: balkanization. In Southeast Asia, as in Europe and any part of the world, he said, outside powers had a vested interest in the balkanization of the region. “We want to ensure,” he said, “a stable Southeast Asia, not a balkanized Southeast Asia. And those countries who are interested, genuinely interested, in the stability of Southeast Asia, the prosperity of Southeast Asia, and better economic and social conditions, will welcome small countries getting together to pool their collective resources and their collective wisdom to contribute to the peace of the world.” The goal of ASEAN, then, is to create, not to destroy. This, the Foreign Minister of Thailand, Thanat Khoman, stressed when it was his turn to speak. At a time when the Vietnam conflict was raging and American forces seemed forever entrenched in Indochina, he had foreseen their eventual withdrawal from the area and had accordingly applied himself to adjusting Thailand’s foreign policy to a reality that would only become apparent more than half a decade later. He must have had that in mind when, on that occasion, he said that the countries of Southeast Asia had no choice but to adjust to the exigencies of the time, to move toward closer cooperation and even integration. Elaborating on ASEAN objectives, he spoke of “building a new society that will be responsive to the needs of our time and efficiently equipped to bring about, for the enjoyment and the material as well as spiritual advancement of our peoples, conditions of stability and progress. Particularly what millions of men and women in our part of the world want is to erase the old and obsolete concept of domination and subjection of the past and replace it with the new spirit of give and take, of equality and partnership. More than anything else, they want to be master of their own house and to enjoy the inherent right to decide their own destiny …” While the nations of Southeast Asia prevent attempts to deprive them of their freedom and sovereignty, he said, they must first free themselves from the material impediments of ignorance, disease and hunger. Each of these nations cannot accomplish that alone, but by joining together and cooperating with those who have the same aspirations, these objectives become easier to attain. Then Thanat Khoman concluded: “What we have decided today is only a small beginning of what we hope will be a long and continuous sequence of accomplishments of which we ourselves, those who will join us later and the generations to come, can be proud. Let it be for Southeast Asia, a potentially rich region, rich in history, in spiritual as well as material resources and indeed for the whole ancient continent of Asia, the light of happiness and well-being that will shine over the uncounted millions of our struggling peoples.” The Foreign Minister of Thailand closed the inaugural session of the Association of Southeast Asian Nations by presenting each of his colleagues with a memento. Inscribed on the memento presented to the Foreign Minister of Indonesia, was the citation, “In recognition of services rendered by His Excellency Adam Malik to the ASEAN organization, the name of which was suggested by him.” And that was how ASEAN was conceived, given a name, and born. It had been barely 14 months since Thanat Khoman brought up the ASEAN idea in his conversations with his Malaysian and Indonesian colleagues. In about three more weeks, Indonesia would fully restore diplomatic relations with Malaysia, and soon after that with Singapore. That was by no means the end to intra-ASEAN disputes, for soon the Philippines and Malaysia would have a falling out on the issue of sovereignty over Sabah. Many disputes between ASEAN countries persist to this day. But all Member Countries are deeply committed to resolving their differences through peaceful means and in the spirit of mutual accommodation. Every dispute would have its proper season but it would not be allowed to get in the way of the task at hand. And at that time, the essential task was to lay the framework of regional dialogue and cooperation. The two-page Bangkok Declaration not only contains the rationale for the establishment of ASEAN and its specific objectives. It represents the organization’s modus operandi of building on small steps, voluntary, and informal arrangements towards more binding and institutionalized agreements. All the founding member states and the newer members have stood fast to the spirit of the Bangkok Declaration. Over the years, ASEAN has progressively entered into several formal and legally-binding instruments, such as the 1976 Treaty of Amity and Cooperation in Southeast Asia and the 1995 Treaty on the Southeast Asia Nuclear Weapon-Free Zone. Against the backdrop of conflict in the then Indochina, the Founding Fathers had the foresight of building a community of and for all Southeast Asian states. Thus the Bangkok Declaration promulgated that “the Association is open for participation to all States in the Southeast Asian region subscribing to the aforementioned aims, principles and purposes.” ASEAN’s inclusive outlook has paved the way for community-building not only in Southeast Asia, but also in the broader Asia Pacific region where several other inter-governmental organizations now co-exist. The original ASEAN logo presented five brown sheaves of rice stalks, one for each founding member. Beneath the sheaves is the legend “ASEAN” in blue. These are set on a field of yellow encircled by a blue border. Brown stands for strength and stability, yellow for prosperity and blue for the spirit of cordiality in which ASEAN affairs are conducted. When ASEAN celebrated its 30th Anniversary in 1997, the sheaves on the logo had increased to ten – representing all ten countries of Southeast Asia and reflecting the colors of the flags of all of them. In a very real sense, ASEAN and Southeast Asia would then be one and the same, just as the Founding Fathers had envisioned. This article is based on the first chapter of ASEAN at 30, a publication of the Association of Southeast Asian Nations in commemoration of its 30th Anniversary on 8 August 1997, written by Jamil Maidan Flores and Jun Abad.
Act 3, Scene 2 of 'A Midsummer Night's Dream': order is restored in the forest