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Isolation and Purification of Muscle Proteins, 2008.
This paper discusses the isolation and purification of actin and myosin in skeletal myofibrils.
1,791 words (approx. 7.2 pages), 7 sources, APA, $ 57.95
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Abstract
The writer explains that in the set of experiments discussed in the paper, myosin and actomyosin were isolated and gradually purified from rabbit muscle myofibrils. The two proteins were initially precipitated together out of solution, in order to remove any impurities. Then, the two proteins could be separated from each other, by taking advantage of differential solubility. The writer notes that after each time they were re-suspended or redissolved, the solutions were centrifuged in order to further improve purity. Any solution containing the contractile proteins or ATP were kept on ice during the experiments, and stored in a freezer at all other times. The writer discusses that using the Bradford protein assay and the SDS-PAGE, the concentrations and weights of the purified proteins in the final solutions were measured. For all protein samples, no appreciable concentration of protein could be detected after diluting the samples by 100 times. However, the other two dilutions yielded normal results.
Outline:
Abstract
Introduction
Materials and Methods
Results
Discussion
From the Paper
"The head of the myosin is the part which interacts with the other molecules. Without ATP, the myosin head is bound tightly to the actin, called the rigor state. However, ATP weakens this interaction by opening a cleft in the myosin head and disrupting the actin-binding site. When the myosin head is free of actin, it hydrolyzes ATP to ADP. This causes a conformational change in the head that moves it to a new position, closer to the (+) end of the actin filament, (away from the origin site) where it reattaches. The dissociation of the phosphate from ATP also causes a conformational change, this time in the myosin head. As a result, myosin returns to its original state (the rigor state). Because myosin is still bound to actin, this conformational change exerts a force that causes myosin to move the actin filament. This is the power stroke. Essentially, contraction is a series of these power strokes by the actomyosin complex, the myosin head is moving along the actin filament through constant detachment and reattachment."
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Measuring Speeds, 2006.
This paper examines mobile eukaryotic cells.
1,063 words (approx. 4.3 pages), 5 sources, APA, $ 37.95
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Abstract
The writer notes that the objective of the laboratory describe in the paper is to observe mobile cells and their characteristics. Three distinct samples are viewed: plant cells from an Elodea leaf, a eukaryotic animal cell called Tetrahymena pyriformis, and myofibrils from a rabbit muscle. The writer points out that when movement is detected in the plant and animal cells, it can lead to calculations of speed. Both intracellular and inter-cellular movement is exemplified in the samples. The writer notes that cells are not only observed under natural conditions, but also after biochemical alterations. The effects of these biochemical changes are also noted. The addition of methyl cellulose enables more accurate observation of the animal cells, since it reduces their speed. The writer concludes that when the ATP was added, the decrease in size proved that the myofibrils are responsible for the muscular function and that the muscle is dependant on the myofibrils successfully working together. However, each cluster of myofibrils appeared to be structurally independent, meaning it was not connected to any other cluster.
Outline:
Introduction
Materials and Methods
Discussion
References
From the Paper
"The Tetrahymena cells were all similar in size, and were either circular or elliptical in shape. Their nuclei and cytoplasms were clearly seen, but any other organelles were difficult to distinguish. Whether they moved horizontally, vertically or diagonally, linear motion was consistent in all the cells. It also seemed like they each one followed a unique path across the field of view. After adding methyl cellulose to these cells, their movement became significantly slower, and deceleration continued until the cells stopped moving altogether. However, their movement also became random, sporadic and generally unpredictable, since they did not seem to be following any particular path. As well, some cells began moving in a circular motion, as if around an axis, and many cells began to gather in large groups once they stopped moving."
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Isolation and Purification of Lysozyme, 2007.
This paper looks at an experiment in an enzyme purification lab for the purification of lysozyme.
2,117 words (approx. 8.5 pages), 5 sources, APA, $ 66.95
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Abstract
The writer explains that in this experiment, lysozyme was purified from egg white solution into 24 fractions using gel column chromatography. The writer points out that the odd-numbered fractions were then assayed in order to determine the enzymatic activity of lysozyme, while the even-numbered fractions were assayed for total protein content, using the Bradford protein assay procedure. The writer notes that lysozyme is one of the most well-known enzymes, being abundant in mucus, tears, and albumen (commonly known as egg white).
The writer concludes that the purification of lysozyme from egg white was only somewhat successful since the estimated value of the molecular weight, 14.25 kDa, is practically the same as the known weight of 14.3 kDa. However, the specific activity, calculated at 400 units/mg, was significantly less than the expected specific activity of 25 000 units/mg of protein.
Outline:
Abstract
Introduction
Materials and Methods
Results
Calculations
Discussion
Conclusion
From the Paper
"Lysozyme is itself composed of 129 amino acids, including four disulfide bridges and three sets of alpha helices. The enzyme's active site consists of a long groove that can hold as many as six polysaccharides. According to past experiments, specific activity of lysozyme from egg white is approximately 25 000 units/mg. This is the expected result for this experiment. However, one factor that influences the specific activity is the actual column and type of chromatography being used, since accuracy differs among the different types of chromatographies. Therefore, some are able to purify enzymes better than others, giving a more accurate specific activity. In addition to obtaining the specific activity, molecular weight of the enzyme can be determined by comparing the fraction in which most of the enzyme eluted with the fractionation range."
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A Chemical Investigation of Fragrances, 2007.
A discussion of the discovery and development of fragrances, focusing on their chemical make-up and manufacturing process.
1,664 words (approx. 6.7 pages), 13 sources, MLA, $ 54.95
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Abstract
This paper looks into the chemical make-up manufacturing processes of fragrances. It begins by discussing the history of fragrances and their uses. It specifically discusses the discovery and development of fragrances. The paper also looks briefly at the shortcomings of fragrances that may pose health risks and other problems.
Table of Contents:
Introduction
Chemistry
Manufacturing Process
Insights
Summary-Conclusions
Appendix
From the Paper
"Many substantive (long-lasting) odorants are known, but a great number of them are too volatile to be perceived more than a few hours after their application. This is the reason why more efficient and effective fragrance-delivery systems, especially for laundry-care products, are intensely sought. The use of "prodrugs", an inactive drug derivative that is converted in the body into its active form, is a well-established technology to improve the oral bioavailability or the penetration across biological membranes. This led to the development of a wide range of precursors that are cleaved by hydrolysis during the laundry process to generate in situ fragrance materials, for example, aldehydes and ketones derived from oxazolidines and ionones and damascones from sz-amino compounds have been developed by Procter & Gamble Fragrance chemists are still looking for new systems with improved stability and release properties."
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Alternative Fuels, 2008.
This paper analyzes hydrogen and ethanol as potential replacements for gasoline.
3,799 words (approx. 15.2 pages), 8 sources, APA, $ 104.95
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Abstract
The paper considers the advantages and disadvantages of hydrogen and ethanol and determines that hydrogen is not a feasible alternative fuel until technology is developed to hold higher quantities. The paper explains why ethanol is the better alternative of the two and concludes that if we adopt ethanol as the fuel of the future, we are sure to have a cleaner and greener earth. The paper includes full color images.
Outline:
Hydrogen
Hydrogen Production
Hydrogen Storage
Hydrogen Transportation and Distribution
Production of Ethanol
Storage of Ethanol
Conclusion
From the Paper
"Hydrogen is one of the many competitors looking to replace gasoline at the pumps. It has many advantages over an ethanol fuel, hydrogen requires less heat to ignite than ethanol, which means that more energy is used for powering the vehicle as opposed to igniting the fuel. (2006) In addition, its flame gives off much less radiant heat than a hydrocarbons flame, yet the flame is just as hot. (2006) Hydrogen's energy produced per unit of mass is larger than that of hydrocarbon fuels by a factor of 2.8. (Snyder, 2006). The higher specific energy means that the car can produce more heat energy for the same amount of fuel mass."
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Linus Carl Pauling, 2008.
This paper looks at the many accomplishments of the chemist Linus Carl Pauling.
1,061 words (approx. 4.2 pages), 5 sources, MLA, $ 37.95
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Abstract
The paper reveals that Pauling has been labeled the premier chemist of the twentieth-century for his work and awards. The paper describes Pauling's birth and childhood, college life, family life, and his many accomplishments. This includes his works on crystal structures, the nature of chemical bonds, the use of Vitamin C to maintain and restore health, as well as his efforts to bring about world peace.
Outline:
Thesis Statement
I. Linus Carl Pauling
II. Accomplishments
From the Paper
"You can find Linus Carl Pauling in many areas of research. This man basically wore a coat of many colors. Pauling was a chemist, physicist, humanitarian, nutrition expert, author, educator, and family man. Having accomplishments that are a mile long--Pauling has been labeled the premier chemist of the twentieth-century for his work and awards. (Wiki, 2007)
"Linus Carl Pauling, was born on February 28, 1901, in the town of Portland, Oregon. (Hutchinson, 1999) His parents were Herman and Isabelle Pauling, and he had two younger sisters. Pauling's, father died in 1910, leaving his mother and the children to make it on their own. Pauling continued on through high school, but did not graduate; because the high school required everyone to take a civics class and Pauling, felt he could learn civics on his own."
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Fluoridation Of Drinking Water, 2005.
An examination of the fluorine in the drinking water in America.
2,358 words (approx. 9.4 pages), 9 sources, $ 72.95
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Abstract
This paper examines the fluoridation of drinking water, specifically in the United States. It explains that fluoridation began in the early 20th century with the aim of improving dental health and with the introduction of fluoridated water into community supplies in some countries, reductions in the rates of decayed, missing, and filled teeth (DMFT) among children occurred. The paper looks at how the World Health Organisation, the United States and the E.U. all advocate fluoridation as an effective method of reducing dental caries, and how only the USA, Britain, Australia and Ireland and a few other countries have fully adopted its use in spite of these world health guidelines. The paper also points out how the engineer plays a key role in implementing the use of fluorine and must act responsibly due to its toxic nature and potentially fatal consequences of incorrect use. The paper concludes that the safety and necessity of fluorine in the drinking water in America needs to be monitored with more studies and research by qualified, well-funded, scientific groups.
Table of Contents:
Introduction. What is Fluorine?
Fluoridation History
How Fluoridation Works
Why Fluoridate?
The Engineer and Fluoridation
Fluoridation And The Law
Some Interesting Quotes on the Subject of Fluoridation
Conclusions
From the Paper
"Fluoride is usually added to water samples in solution form because in powder form (e.g. Sodium Fluoride, Sodium Fluorosilicate, etc.) it is toxic, dangerous to handle and must be stored in dust tight containers. Thus fluorine is often added as hydrofluorosilicic acid (H2SiF6).
This acid is safer because if it is spilt on the skin it can easily be washed off using cold water. This acid is stored in water treatment facilities in tanks. The tanks are lined with corrosion resistant rubber lining. Fluoridation usually takes place after all other treatments of the drinking water have been carried out. It must be done after water has been softened because ions in the water interfere with the fluoride content. The water must be mixed thoroughly before it leaves the facility, as fluoride is toxic in higher concentrations."
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Chemical and Biological Warfare, 2006.
This paper examines the issue of chemical and biological weapons and war.
4,855 words (approx. 19.4 pages), 9 sources, APA, $ 123.95
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Abstract
In this article the writer discusses that, throughout time, the quest to dominate another is limited only to the imagination of one man poised against the other. The writer points out that sometimes common flu symptoms such as headache, dizziness, nausea, vomiting, coughing, and shortness of breath are the first signs of chemical and biological warfare (CBW). The writer maintains that for some reason, the more one searches for answers to counter the effects of CBW the worse it gets. In this essay, discussion centers upon the 1972 Biological Weapon's Convention and the Geneva Protocol. The writer focuses on scientific research in this regard and identifies several items that are being used to help detect biological and chemical agents.
Outline:
Abstract
Advantages
Disadvantages
Chemical Agents and their Effects
From the Paper
"Throughout history, chemical and biological weapons (CBW), warriors and terrorists have used a wide range of tactics and techniques to help defeat their enemy on and off the battlefield. These weapons are used in war to gain the upper advantage against a more formidable adversary, to enhance the political status of a rogue terrorist group, or to cripple the economy of a nation from the simple mailing of a threatening letter with powder. Whatever the reason, the unknown effects of a release can be devastating. Law enforcement personnel who respond to the initial crisis of a release or assist with the aftermath have to know the difference between a chemical and a biological agent release. These weapons of war also have evolved from throwing rocks and sticks at each other to the unthinkable weapons of mass destruction called bioterrorism. You may ask yourself, what is bioterrorism? The Center for Disease Control defines bioterrorism as the intentional or threatened use of bacteria, fungi, or toxins from living organisms to produce death or disease in humans, animals, or plants and involves intimidation of nations or people to accomplish political or social ends."
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The Mutation Cluster Region of the APC Gene, 2007.
An examination of the mutation cluster region of the APC gene and its role in colon carcinogenesis.
4,146 words (approx. 16.6 pages), 27 sources, APA, $ 111.95
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Abstract
This paper is an examination of the mechanisms of colon tumorigenesis involving the mutation cluster region of the APC gene. There is an explanation of colon carcinogenesis including an analysis of the Wnt signaling pathway, the roles of the APC gene's different domains, "Knudon's two- hit hypothesis and the "just right" level of signaling theory. The paper also includes a critical discussion about the scientific arguments and research evidence that exists to challenge current understanding of the underlying mechanisms of colon tumorigenesis. One illustration is included which depicts the varying domains of the APC gene.
From the Paper
"Colorectal cancer is the third most common form of cancer and the second leading cause of death in the western world. Nearly 34,900 people are diagnosed with it in the U.K each year and about 16,000 of these die. About 15% of colorectal cancers are hereditary. Hereditary conditions are divided into two categories: the polyposis and the non polyposis types. Two hereditary conditions that have been identified are Familial Adenomatous Polyposis Coli (FAP) and Hereditary Non Polyposis Colorectal Cancer (HNPCC). The adenomatous polyposis coli (APC) gene is known to be mutated in all cases of FAP but this condition only accounts for less than 1% of colorectal cancer cases. The condition HNPCC results when mutation occurs in the DNA mismatch repair genes MSH2 and MLH-1 leading to microsatellite instability and defective DNA repair. Non inherited mutations of the APC gene have been detected in over 85% of the remaining sporadic colorectal cancers. "
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Playing with Food: Hidden Sugars, 2006.
A study on sugars hidden in so-called sugar-free samples, as scientifically detected by the Benedict's Test.
1,604 words (approx. 6.4 pages), 5 sources, APA, $ 52.95
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Abstract
This paper takes a look at our health-conscious society, which indulges in the use of sugar-free foods and beverages that have steadily dominated the market. The paper discusses how recent controversies that question product credibility have circulated, thus prompting various analyses on food content. By using the principles behind the Benedict's test, this study employs techniques used to test the presence of chemical compounds in food, particularly in sugar-free samples.
From the Paper
"While the Benedict's reagent can analyze the sugar content of most food products, the conducted experiment focused on sugar-free samples alone. Presenting novel results, this smaller scope diverts from previous experiments involving pure sugar concentrates."
"For the experiment, distilled water, small samples of selected sugar-free food, and a small bottle of Benedict's solution were prepared. Along with test tubes equivalent in number to the samples tested, the experiment required laboratory equipments inclusive of a Bunsen burner, a tripod, a dropper, and a beaker."
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