Hello guys there r near 3500 engineering collages in india but, i m giving u the latest top 50 engineering collages of india .
RANK Name of Institute
1 Indian Institute of Technology IIT Kanpur
2 Indian Institute of Technology IIT Kharagpur
3 Indian Institute of Technology IIT Bombay
4 Indian Institute of Technology IIT Madras
5 Indian Institute of Technology IIT Delhi
6 BITS Pilani
7 IIT Roorkee
8 IT-BHU
9 IIT-Guwahati
10 College of Engg , Anna University, Guindy
11 Jadavpur University , Faculty of Engg & Tech., Calcutta
12 Indian School of Mines, Dhanbad
13 NIT- National Institute of Technology Warangal
14 BIT, Mesra
15 NIT- National Institute of Technology Trichy
16 Delhi College of Engineering , Delhi
17 Punjab Engineering College, Chandigarh
18 NIT- National Institute of Technology, Suratkal
19 Motilal Nehru National Inst. of Technology, Allahabad
20 Thapar Inst of Engineering & Technology, Patiala
21 Bengal Eng and Science University , Shibpur
22 MNIT Malviya National Institute of Technology Bhopal
23 PSG College of Technology Coimbatore
24 IIIT - International Institute of Information Technology Hyderabad
25 Harcourt Butler Technological Institute (HBTI), Kanpur
26 Malviya National Institute of Technology, Jaipur
27 VNIT - Visvesvaraya National Institute of Technology Nagpur
28 NIT- National Institute of Technology, Calicut
29 Dhirubhai Ambani IICT, Gandhi Nagar
30 Osmania Univ. College of Engineering, Hyderabad
31 College of Engineering , Andhra University, Vishakhapatnam
32 Netaji Subhas Institute of Technology, New Delhi
33 NIT- National Institute of Technology Kurukshetra
34 NIT- National Institute of Technology Rourkela
35 SVNIT Surat
36 Govt. College of Engineering, Pune
37 Manipal Institute of Technology, Manipal
38 JNTU Hyderabad
39 R.V. College of Engineering Bangalore0
40 NIT- National Institute of Technology Jamshedpur
41 University Visvesvaraya College of Engg. Bangalore
42 VJTI Mumbai
43 Vellore Institute of Technology, Vellore
44 Coimbatore Institute of Technology, Coimbatore
45 SSN College of Engineering, Chennai
46 IIIT, Allahabad
47 College of Engineering, Trivandrum
48 NIT Durgapur
49 SIT Calcutta
50 MBM Jodhpur rajasthan
THERE IS TOP 10 PRIVET ENGINEERING COLLAGES OF INDIA :
1 BITS
2 BIT Mesra
3 PSG College of Technology
4 Thapar Inst. of Engineering & Technology
5 Dhirubhai Ambani Inst. of Infocom. Tech
6 Manipal Institute of Technology
7 Vellore Institute of Technology
8 VJTI
9 SSN College of Engineering
10 RV College of Engineering
Sunday, July 19, 2009
Sunday, April 6, 2008
Friendship
Friendship :
Small-minded administrators and authority figures like to speak in clichés. All my life I heard the same trite line: “ You can tell a lot about a person by the friends they keep.” The black sheep of the honors program, I hung out with the so-called “ losers.” During my freshman year, not a day went by when a teacher or family member did not deride my closest friends and warn me that by hanging out with “ bad seeds” I would fall into a downward spiral, never graduate college, and have a miserable life. They thought that they had me figured out. One day, while my ninth grade math teacher, Mr. Pedersen, was reviewing some math concepts with me, my friend Mariam ran by the classroom, stuck her head in the doorway, called out: “ Hi Yassee, ” and then ran away. Mr. Pedersen looked at me coldly and said with a scowl: “ How can you call yourself an Honors student? A real honors student doesn’t associate with people like that!” I wanted to ask him how he could call himself a teacher; after all, a real teacher is supposed to want to help everyone. Instead, I sat silent, stunned by his ignorance and cruelty. He wanted me to drop my childhood friends simply because they didn’t place the same importance on schoolwork that I do. If he had thought before speaking, he would have realized that people like him, rather than people like my friends, are better able to turn good students into poor ones by discouraging them with ridiculous comments. I would never slight Mariam. One of my closest friends in freshman year, she was also a below average, non-college bound student. Many of the adults in my life, especially my parents and teachers, would look at those closest to me: Mariam, Alisa, Zena, Lianne, and Marvin, and ask how I could call these “ low-life losers” my friends. But such questions show a lack of understanding of the nature of friendship. Friendship is unconditional and uncritical, based only on mutual respect and the ability to enjoy each other’ s company. These authority figures never saw the way one of us could do something outrageous, and the rest of us would joke about it for days. We could have fun doing absolutely nothing at all - because the company we provided each other with was enough. Rather than discussing operas, Lewinsky, or the weather, we enjoyed just hanging around each other without any one of us trying to outsmart the others. Still, I realize that these adults had a point to be concerned about the direction my friends were heading; I also was concerned for them, but I wasn’t about to leave them. Many times I would advise my friends that some activity may be dangerous or to think things through before doing something, but I would never claim to hold the moral high ground and to condescend to them. When Marvin would begin rolling joints, when Alisa would tell me she skipped school because of a hangover, or when Mariam would tell me that her new boyfriend was in a street gang, I expressed my discomfort with their actions. However, I never blackmailed them with the threat of taking my friendship away. Contrary to the commercials on television, you can have friends who use drugs. In fact, probably everyone does without realizing it. In my junior year, AP U.S. History class, the teacher, Mr. Jacobsen, addressed the class saying: “ I bet none of you have ever seen a drug deal!” With a look of absolute certainty and an odd smile on his face he scanned the room. “ I’ve seen a drug deal before, ” I answered. Everyone in the room turned to look at me, either gasping or in disbelief. I realized that maybe my experiences thus far were a typical of most of my honor student friends. Despite our varying experiences, I still maintained many friends who were excellent students. Yogita, Nitin, Hans, Vishal, Saurabh, Anuj, Nick, and I have had almost every class together since eighth grade. Nitin and I both love to shop and eat. What is different about shopping with Nitin, however, is that we argue about the necessity of a high sales tax or discuss the effectiveness of the acting welfare system. Yogita and I always go to the library together and “ pull all nighters” at her house. While I do enjoy accomplishing my academic goals and working with this highly motivated group of friends, I also enjoy “ the losers, ” who to me seem much more sincere and loyal. In retrospect, I wouldn’t change my ninth grade experience, because I learned many of life’ s important lessons from my friends and the ignorance of teachers and administrators. It’ s sad to say, but in many of my friends’ dangerous actions, I saw what I never wanted to become. In the future, I’ d like to continue helping adolescents, in addition to my studies. I have been fortunate thus far in being able to reach out to them through programs like C.H.A.N.G.E. For my efforts, I have been recognized and was honored to receive the 1998 Operation Pride Youth Award for my dedication to helping other kids live a substance free lifestyle. My familiarity with teenagers from all walks of life greatly enhances my ability to both identify with and influence others. I will be a successful adult in the future because I am willing to work with everyone and to give everyone a chance. Hopefully, I will also have the chance to change other kids’ lives for the better.
Tuesday, February 5, 2008
Biochemistry
Biochemistry Transformations
Biochemistry is the study of the chemical processes and transformations in living organisms. It deals with the structure and function of cellular components, such as proteins, carbohydrates, lipids, nucleic acids, and other biomolecules. Chemical biology aims to answer many questions arising from biochemistry by using tools developed within synthetic chemistry.Although there are a vast number of different biomolecules, many are complex and large molecules (called polymers) that are composed of similar repeating subunits (called monomers). Each class of polymeric biomolecule has a different set of subunit types. For example, a protein is a polymer made up of 40 or more amino acids. Biochemistry studies the chemical properties of important biological molecules, like proteins, in particular the chemistry of enzyme-catalyzed reactions. The biochemistry of cell metabolism and the endocrine system has been extensively described. Other areas of biochemistry include the genetic code, protein synthesis, cell membrane transport, and signal transduction.
Distribution of Terrestrial Biochemistry
This article only discusses terrestrial biochemistry (carbon- and water-based), as all the life forms we know are on Earth. Since life forms alive today are hypothesized by most to have descended from the same common ancestor, they would naturally have similar biochemistries, even for matters that seem to be essentially arbitrary, such as handedness of various biomolecules. It is unknown whether alternative biochemistries are possible or practical. Originally, it was generally believed that life was not subject to the laws of science the way non-life was. It was thought that only living beings could produce the molecules of life from other, previously existing biomolecules. Then, in 1828, Friedrich Wöhler published a paper about the synthesis of urea, proving that organic compounds can be created artificially. The dawn of biochemistry may have been the discovery of the first enzyme, diastase today called amylase), in 1833 by Anselme Payen. Eduard Buchner contributed the first demonstration of a complex biochemical process outside of a cell in 1896 alcoholic fermentation in cell extracts of yeast. Although the term “biochemistry” seems to have been first used in 1882, it is generally accepted that the formal coinage of biochemistry occurred in 1903 by Carl Neuberg, a German chemist. Previously, this area would have been referred to as physiological chemistry. Since then, biochemistry has advanced, especially since the mid-20th century, with the development of new techniques such as chromatography, X-ray diffraction, NMR spectroscopy, radioisotopic labeling, electron microscopy and molecular dynamics simulations. These techniques allowed for the discovery and detailed analysis of many molecules and metabolic pathways of the cell, such as glycolysis and the Krebs cycle citric acid cycle.Today, the findings of biochemistry are used in many areas, from genetics to molecular biology and from agriculture to medicine.
Carbohydrates&Monosaccharides
However, there are a lot of Type O blonds out there. If you find that the crime scene has footprints from a pair of Nike Air Jordans with a distinctive tread design and the suspect, in addition to being type O and blond, is also wearing Air Jordans with the same tread design, then you are much closer to linking the suspect with the crime scene. In this way, by accumulating bits of linking evidence in a chain, where each bit by itself isn't very strong but the set of all of them together is very strong, you can argue that your suspect really is the right person. With DNA, the same kind of thinking is used; you can look for matches based on sequence or on numbers of small repeating units of DNA sequence at a number of different locations on the person's genome; one or two even three aren't enough to be confident that the suspect is the right one, but four sometimes five are used and a match at all five is rare enough that you or a prosecutor or a jury can be very confident beyond a reasonable doubt that the right person is accused Experts point out that using DNA forensic technology is far superior to eyewitness accounts, where the odds for correct identification are about 50:50.The more probes used in DNA analysis, the greater the odds for a unique pattern and against a coincidental match, but each additional probe adds greatly to the time and expense of testing. Four to six probes are recommended. Testing with several more probes will become routine, observed John Hicks Alabama State Department of Forensic Services. He predicted that, DNA chip technology in which thousands of short DNA sequences are embedded in a tiny chip will enable much more rapid, inexpensive analysis using many more probes, and raising the odds against coincidental matches. RFLP is a technique for analyzing the variable lengths of DNA fragments that result from digesting a DNA sample with a special kind of enzyme.
Protein Synthesis
GlucoseThe simplest type of carbohydrate is a monosaccharide, which among other properties contains carbon, hydrogen, and oxygen, mostly in a ratio of 1:2:1 generalized formula CnH2nOn, where n is at least . Glucose, one of the most important carbohydrates, is an example of a monosaccharide. So is fructose, the sugar that gives fruits their sweet taste. Some carbohydratesespecially after condensation to oligo and polysaccharides contain less carbon relative to H and O, which still are present in ratio. Monosaccharides can be grouped into aldoses having an aldehyde group at the end of the chain, e. g. glucose and ketoses having a keto group in their chaine. Both aldoses and ketoses occur in an equilibrium between the open-chain forms and starting with chain lengths of C4 cyclic forms. These are generated by bond formation between one of the hydroxy groups of the sugar chain with the carbon of the aldehyde or keto group in a hemiacetal bond. This leads to saturated five membered in furanoses or six-membered in pyranoses heterocyclic rings containing one O as heteroatom. ordinary table sugar and probably the most familiar carbohydrate.Two monosaccharides can be joined together using dehydration synthesis, in which a hydrogen atom is removed from the end of one molecule and a hydroxyl group (OH) is removed from the other; the remaining residues are then attached at the sites from which the atoms were removed. The HOH or H2O is then released as a molecule of water, hence the term dehydration. The new molecule, consisting of two monosaccharides, is called a disaccharide and is conjoined together by a glycosidic or ether bond. The reverse reaction can also occur, using a molecule of water to split up a disaccharide and break the glycosidic bond; this is termed hydrolysis. The most well-known disaccharide is sucrose, ordinary sugar in scientific contexts, called table sugar or cane sugar to differentiate it from other sugars. Sucrose consists of a glucose molecule and a fructose molecule joined together. Another important disaccharide is lactose, consisting of a glucose molecule and a galactose molecule. As most humans age, the production of lactase, the enzyme that hydrolyzes lactose back into glucose and galactose, typically decreases. This results in lactase deficiency, also called lactose intolerance.Sugar polymers are characterised by having reducing or non-reducing ends. A reducing end of a carbohydrate is a carbon atom which can be in equilibrium with the open-chain aldehyde or keto form. If the joining of monomers takes place at such a carbon atom, the free hydroxy group of the pyranose or furanose form is exchanged with an OH-side chain of another sugar, yielding a full acetal. This prevents opening of the chain to the aldehyde or keto form and renders the modified residue non-reducing. Lactose contains a reducing end at its glucose moiety, whereas the galactose moiety form a full acetal with the C4-OH group of glucose. Saccharose does not have a reducing end because of full acetal formation between the aldehyde carbon of glucose and the keto carbon of fructos
Oligosaccharides and Polysaccharides
Cellulose as polymer of ß-D-glucoseWhen a few around three to six monosaccharides are joined together, it is called an oligosaccharide . These molecules tend to be used as markers and signals, as well as having some other uses.Many monosaccharides joined together make a polysaccharide. They can be joined together in one long linear chain, or they may be branched. Two of the most common polysaccharides are cellulose and glycogen, both consisting of repeating glucose monomers.Cellulose is made by plants and is an important structural component of their cell walls. Humans can neither manufacture nor digest it. Glycogen, on the other hand, is an animal carbohydrate; humans use it as a form of energy storag.Use of carbohydrates as an energy sourceSee also carbohydrate metabolism Glucose is the major energy source in most life forms. For instance, polysaccharides are broken down into their monomers glycogen phosphorylase removes glucose residues from glycogen Disaccharides like lactose or sucrose are cleaved into their two component monosaccharides. Glucose is mainly metabolized by a very important and ancient ten-step pathway called glycolysis, the net result of which is to break down one molecule of glucose into two molecules of pyruvate; this also produces a net two molecules of ATP, the energy currency of cells, along with two reducing equivalents in the form of converting NAD+ to NADH. This does not require oxygen; if no oxygen is available or the cell cannot use oxygen, the NAD is restored by converting the pyruvate to lactate or to ethanol plus carbon dioxide Other monosaccharides like galactose and fructose can be converted into intermediates of the glycolytic pathway.In aerobic cells with sufficient oxygen, like most human cells, the pyruvate is further metabolized. It is irreversibly converted to acetyl, giving off one carbon atom as the waste product carbon dioxide, generating another reducing equivalent as NADH. The two molecules acetyl-CoA from one molecule of glucosethen enter the citric acid cycle, producing two more molecules of ATP, six more NADH molecules and two reduced quinones via FADH2 as enzyme-bound cofactor, and releasing the remaining carbon atoms as carbon dioxide. The produced NADH and quinol molecules then feed into the enzyme complexes of the respiratory chain, an electron transport system transferring the electrons ultimately to oxygen and conserving the released energy in the form of a proton gradient over a membrane inner mitochondrial membrane in eukaryotes. Thereby, oxygen is reduced to water and the original electron acceptors NAD+ and quinone are regenerated. This is why humans breathe in oxygen and breathe out carbon dioxide. The energy released from transferring the electrons from high-energy states in NADH and quinol is conserved first as proton gradient and converted to ATP via ATP synthase. This generates an additional 28 molecules of ATP 24 from the 8 NADH + 4 from the 2 quinols, totaling to 32 molecules of ATP conserved per degraded glucose two from glycolysis two from the citrate cycle. It is clear that using oxygen to completely oxidize glucose provides an organism with far more energy than any oxygen-independent metabolic feature, and this is thought to be the reason why complex life appeared only after Earth's atmosphere accumulated large amounts of oxygen.
Gluconeogenesis & Proteins
In vertebrates, vigorously contracting skeletal muscles during weightlifting or sprinting, for example do not receive enough oxygen to meet the energy demand, and so they shift to anaerobic metabolism, converting glucose to lactate. The liver regenerates the glucose, using a process called gluconeogenesis. This process is not quite the opposite of glycolysis, and actually requires three times the amount of energy gained from glycolysis six molecules of ATP are used, compared to the two gained in glycolysis. Analogous to the above reactions, the glucose produced can then undergo glycolysis in tissues that need energy, be stored as glycogen starch in plants, or be converted to other monosaccharides or join A schematic of hemoglobin. The red and blue ribbons represent the protein globin; the green structures are the heme groups.Like carbohydrates, some proteins perform largely structural roles. For instance, movements of the proteins actin and myosin ultimately are responsible for the contraction of skeletal muscle. One property many proteins have is that they specifically bind to a certain molecule or class of molecules they may be extremely selective in what they bind. Antibodies are an example of proteins that attach to one specific type of molecule. In fact, the enzyme-linked immunosorbent assay (ELISA), which uses antibodies, is currently one of the most sensitive tests modern medicine uses to detect various biomolecules. Probably the most important proteins, however, are the enzymes. These amazing molecules recognize specific reactant molecules called substrates; they then catalyze the reaction between them. By lowering the activation energy, the enzyme speeds up that reaction by a rate of 1011 or more: a reaction that would normally take over 3,000 years to complete spontaneously might take less than a second with an enzyme. The enzyme itself is not used up in the process, and is free to catalyze the same reaction with a new set of substrates. Using various modifiers, the activity of the enzyme can be regulated, enabling control of the biochemistry of the cell as a whole.In essence, proteins are chains of amino acids. An amino acid consists of a carbon atom bound to four groups. One is an amino group,NH2, and one is a carboxylic acid group,COOH although these exist as and under physiologic conditions. The third is a simple hydrogen atom. The fourth is commonly denoted and is different for each amino acid. There are twenty standard amino acids. Some of these have functions by themselves or in a modified form; for instance, glutamate functions as an important neurotransmitter. Generic amino acids in neutral form, as they exist physiologically, and joined together as a dipeptide.Amino acids can be joined together via a peptide bond. In this dehydration synthesis, a water molecule is removed and the peptide bond connects the nitrogen of one amino acid's amino group to the carbon of the other's carboxylic acid group. The resulting molecule is called a dipeptide, and short stretches of amino acids usually, fewer than around thirty are called peptides or polypeptides. Longer stretches merit the title proteins. As an example, the important blood serum protein albumin contains 585 amino acid residues.The structure of proteins is traditionally described in a hierarchy of four levels. The primary structure of a protein simply consists of its linear sequence of amino acids; for ,cinetryptophan-serineglutamate-asparagine-glycine-lysine.dary structure is concerned with local morphology. Some combinations of amino acids will tend to curl up in a coil called an a-helix or into a sheet called a ß-sheet; some a-helixes can be seen in the hemoglobin schematic above. Tertiary structure is the entire three-dimensional shape of the protein. This shape is determined by the sequence of amino acids. In fact, a single change can change the entire structure. The ß chain of hemoglobin contains 146 amino acid residues; substitution of the glutamate residue at position 6 with a valine residue changes the behavior of hemoglobin so much that it results in sickle-cell disease. Finally quaternary structure is concerned with the structure of a protein with multiple peptide subunits, like hemoglobin with its four subunits. Not all proteins have more than one subunit.Ingested proteins are usually broken up into single amino acids or dipeptides in the small intestine, and then absorbed. They can then be joined together to make new proteins. Intermediate products of glycolysis, the citric acid cycle, and the pentose phosphate pathway can be used to make all twenty amino acids, and most bacteria and plants possess all the necessary enzymes to synthesize them. Humans and other mammals, however, can only synthesize half of them. They cannot synthesize isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan, and valine. These are the essential amino acids, since it is essential to ingest them. Mammals do possess the enzymes to synthesize alanine, asparagine, aspartate, cysteine, glutamate, glutamine, glycine, proline, serine, and tyrosine, the nonessential amino acids. While they can synthesize arginine and histidine, they cannot produce it in sufficient amounts for young, growing animals, and so these are often considered essential amino acids.If the amino group is removed from an amino acid, it leaves behind a carbon skeleton called an a-keto acid. Enzymes called transaminases can easily transfer the amino group from one amino acid making it an a-keto acid to another a-keto acid making it an amino acid. This is important in the biosynthesis of amino acids, as for many of the pathways, intermediates from other biochemical pathways are converted to the a-keto acid skeleton, and then an amino group is added, often via transamination. The amino acids may then be linked together to make a protein.A similar process is used to break down proteins. It is first hydrolyzed into its component amino acids. Free ammonia NH3, existing as the ammonium ion NH4 in blood is toxic to life forms. A suitable method for excreting it must therefore exist. Different strategies have evolved in different animals, depending on the animals' needs. Unicellular organisms, of course, simply release the ammonia into the environment. Similarly, bony fish can release the ammonia into the water where it is quickly diluted. In general, mammals convert the ammonia into urea, via t
Biochemistry is the study of the chemical processes and transformations in living organisms. It deals with the structure and function of cellular components, such as proteins, carbohydrates, lipids, nucleic acids, and other biomolecules. Chemical biology aims to answer many questions arising from biochemistry by using tools developed within synthetic chemistry.Although there are a vast number of different biomolecules, many are complex and large molecules (called polymers) that are composed of similar repeating subunits (called monomers). Each class of polymeric biomolecule has a different set of subunit types. For example, a protein is a polymer made up of 40 or more amino acids. Biochemistry studies the chemical properties of important biological molecules, like proteins, in particular the chemistry of enzyme-catalyzed reactions. The biochemistry of cell metabolism and the endocrine system has been extensively described. Other areas of biochemistry include the genetic code, protein synthesis, cell membrane transport, and signal transduction.
Distribution of Terrestrial Biochemistry
This article only discusses terrestrial biochemistry (carbon- and water-based), as all the life forms we know are on Earth. Since life forms alive today are hypothesized by most to have descended from the same common ancestor, they would naturally have similar biochemistries, even for matters that seem to be essentially arbitrary, such as handedness of various biomolecules. It is unknown whether alternative biochemistries are possible or practical. Originally, it was generally believed that life was not subject to the laws of science the way non-life was. It was thought that only living beings could produce the molecules of life from other, previously existing biomolecules. Then, in 1828, Friedrich Wöhler published a paper about the synthesis of urea, proving that organic compounds can be created artificially. The dawn of biochemistry may have been the discovery of the first enzyme, diastase today called amylase), in 1833 by Anselme Payen. Eduard Buchner contributed the first demonstration of a complex biochemical process outside of a cell in 1896 alcoholic fermentation in cell extracts of yeast. Although the term “biochemistry” seems to have been first used in 1882, it is generally accepted that the formal coinage of biochemistry occurred in 1903 by Carl Neuberg, a German chemist. Previously, this area would have been referred to as physiological chemistry. Since then, biochemistry has advanced, especially since the mid-20th century, with the development of new techniques such as chromatography, X-ray diffraction, NMR spectroscopy, radioisotopic labeling, electron microscopy and molecular dynamics simulations. These techniques allowed for the discovery and detailed analysis of many molecules and metabolic pathways of the cell, such as glycolysis and the Krebs cycle citric acid cycle.Today, the findings of biochemistry are used in many areas, from genetics to molecular biology and from agriculture to medicine.
Carbohydrates&Monosaccharides
However, there are a lot of Type O blonds out there. If you find that the crime scene has footprints from a pair of Nike Air Jordans with a distinctive tread design and the suspect, in addition to being type O and blond, is also wearing Air Jordans with the same tread design, then you are much closer to linking the suspect with the crime scene. In this way, by accumulating bits of linking evidence in a chain, where each bit by itself isn't very strong but the set of all of them together is very strong, you can argue that your suspect really is the right person. With DNA, the same kind of thinking is used; you can look for matches based on sequence or on numbers of small repeating units of DNA sequence at a number of different locations on the person's genome; one or two even three aren't enough to be confident that the suspect is the right one, but four sometimes five are used and a match at all five is rare enough that you or a prosecutor or a jury can be very confident beyond a reasonable doubt that the right person is accused Experts point out that using DNA forensic technology is far superior to eyewitness accounts, where the odds for correct identification are about 50:50.The more probes used in DNA analysis, the greater the odds for a unique pattern and against a coincidental match, but each additional probe adds greatly to the time and expense of testing. Four to six probes are recommended. Testing with several more probes will become routine, observed John Hicks Alabama State Department of Forensic Services. He predicted that, DNA chip technology in which thousands of short DNA sequences are embedded in a tiny chip will enable much more rapid, inexpensive analysis using many more probes, and raising the odds against coincidental matches. RFLP is a technique for analyzing the variable lengths of DNA fragments that result from digesting a DNA sample with a special kind of enzyme.
Protein Synthesis
GlucoseThe simplest type of carbohydrate is a monosaccharide, which among other properties contains carbon, hydrogen, and oxygen, mostly in a ratio of 1:2:1 generalized formula CnH2nOn, where n is at least . Glucose, one of the most important carbohydrates, is an example of a monosaccharide. So is fructose, the sugar that gives fruits their sweet taste. Some carbohydratesespecially after condensation to oligo and polysaccharides contain less carbon relative to H and O, which still are present in ratio. Monosaccharides can be grouped into aldoses having an aldehyde group at the end of the chain, e. g. glucose and ketoses having a keto group in their chaine. Both aldoses and ketoses occur in an equilibrium between the open-chain forms and starting with chain lengths of C4 cyclic forms. These are generated by bond formation between one of the hydroxy groups of the sugar chain with the carbon of the aldehyde or keto group in a hemiacetal bond. This leads to saturated five membered in furanoses or six-membered in pyranoses heterocyclic rings containing one O as heteroatom. ordinary table sugar and probably the most familiar carbohydrate.Two monosaccharides can be joined together using dehydration synthesis, in which a hydrogen atom is removed from the end of one molecule and a hydroxyl group (OH) is removed from the other; the remaining residues are then attached at the sites from which the atoms were removed. The HOH or H2O is then released as a molecule of water, hence the term dehydration. The new molecule, consisting of two monosaccharides, is called a disaccharide and is conjoined together by a glycosidic or ether bond. The reverse reaction can also occur, using a molecule of water to split up a disaccharide and break the glycosidic bond; this is termed hydrolysis. The most well-known disaccharide is sucrose, ordinary sugar in scientific contexts, called table sugar or cane sugar to differentiate it from other sugars. Sucrose consists of a glucose molecule and a fructose molecule joined together. Another important disaccharide is lactose, consisting of a glucose molecule and a galactose molecule. As most humans age, the production of lactase, the enzyme that hydrolyzes lactose back into glucose and galactose, typically decreases. This results in lactase deficiency, also called lactose intolerance.Sugar polymers are characterised by having reducing or non-reducing ends. A reducing end of a carbohydrate is a carbon atom which can be in equilibrium with the open-chain aldehyde or keto form. If the joining of monomers takes place at such a carbon atom, the free hydroxy group of the pyranose or furanose form is exchanged with an OH-side chain of another sugar, yielding a full acetal. This prevents opening of the chain to the aldehyde or keto form and renders the modified residue non-reducing. Lactose contains a reducing end at its glucose moiety, whereas the galactose moiety form a full acetal with the C4-OH group of glucose. Saccharose does not have a reducing end because of full acetal formation between the aldehyde carbon of glucose and the keto carbon of fructos
Oligosaccharides and Polysaccharides
Cellulose as polymer of ß-D-glucoseWhen a few around three to six monosaccharides are joined together, it is called an oligosaccharide . These molecules tend to be used as markers and signals, as well as having some other uses.Many monosaccharides joined together make a polysaccharide. They can be joined together in one long linear chain, or they may be branched. Two of the most common polysaccharides are cellulose and glycogen, both consisting of repeating glucose monomers.Cellulose is made by plants and is an important structural component of their cell walls. Humans can neither manufacture nor digest it. Glycogen, on the other hand, is an animal carbohydrate; humans use it as a form of energy storag.Use of carbohydrates as an energy sourceSee also carbohydrate metabolism Glucose is the major energy source in most life forms. For instance, polysaccharides are broken down into their monomers glycogen phosphorylase removes glucose residues from glycogen Disaccharides like lactose or sucrose are cleaved into their two component monosaccharides. Glucose is mainly metabolized by a very important and ancient ten-step pathway called glycolysis, the net result of which is to break down one molecule of glucose into two molecules of pyruvate; this also produces a net two molecules of ATP, the energy currency of cells, along with two reducing equivalents in the form of converting NAD+ to NADH. This does not require oxygen; if no oxygen is available or the cell cannot use oxygen, the NAD is restored by converting the pyruvate to lactate or to ethanol plus carbon dioxide Other monosaccharides like galactose and fructose can be converted into intermediates of the glycolytic pathway.In aerobic cells with sufficient oxygen, like most human cells, the pyruvate is further metabolized. It is irreversibly converted to acetyl, giving off one carbon atom as the waste product carbon dioxide, generating another reducing equivalent as NADH. The two molecules acetyl-CoA from one molecule of glucosethen enter the citric acid cycle, producing two more molecules of ATP, six more NADH molecules and two reduced quinones via FADH2 as enzyme-bound cofactor, and releasing the remaining carbon atoms as carbon dioxide. The produced NADH and quinol molecules then feed into the enzyme complexes of the respiratory chain, an electron transport system transferring the electrons ultimately to oxygen and conserving the released energy in the form of a proton gradient over a membrane inner mitochondrial membrane in eukaryotes. Thereby, oxygen is reduced to water and the original electron acceptors NAD+ and quinone are regenerated. This is why humans breathe in oxygen and breathe out carbon dioxide. The energy released from transferring the electrons from high-energy states in NADH and quinol is conserved first as proton gradient and converted to ATP via ATP synthase. This generates an additional 28 molecules of ATP 24 from the 8 NADH + 4 from the 2 quinols, totaling to 32 molecules of ATP conserved per degraded glucose two from glycolysis two from the citrate cycle. It is clear that using oxygen to completely oxidize glucose provides an organism with far more energy than any oxygen-independent metabolic feature, and this is thought to be the reason why complex life appeared only after Earth's atmosphere accumulated large amounts of oxygen.
Gluconeogenesis & Proteins
In vertebrates, vigorously contracting skeletal muscles during weightlifting or sprinting, for example do not receive enough oxygen to meet the energy demand, and so they shift to anaerobic metabolism, converting glucose to lactate. The liver regenerates the glucose, using a process called gluconeogenesis. This process is not quite the opposite of glycolysis, and actually requires three times the amount of energy gained from glycolysis six molecules of ATP are used, compared to the two gained in glycolysis. Analogous to the above reactions, the glucose produced can then undergo glycolysis in tissues that need energy, be stored as glycogen starch in plants, or be converted to other monosaccharides or join A schematic of hemoglobin. The red and blue ribbons represent the protein globin; the green structures are the heme groups.Like carbohydrates, some proteins perform largely structural roles. For instance, movements of the proteins actin and myosin ultimately are responsible for the contraction of skeletal muscle. One property many proteins have is that they specifically bind to a certain molecule or class of molecules they may be extremely selective in what they bind. Antibodies are an example of proteins that attach to one specific type of molecule. In fact, the enzyme-linked immunosorbent assay (ELISA), which uses antibodies, is currently one of the most sensitive tests modern medicine uses to detect various biomolecules. Probably the most important proteins, however, are the enzymes. These amazing molecules recognize specific reactant molecules called substrates; they then catalyze the reaction between them. By lowering the activation energy, the enzyme speeds up that reaction by a rate of 1011 or more: a reaction that would normally take over 3,000 years to complete spontaneously might take less than a second with an enzyme. The enzyme itself is not used up in the process, and is free to catalyze the same reaction with a new set of substrates. Using various modifiers, the activity of the enzyme can be regulated, enabling control of the biochemistry of the cell as a whole.In essence, proteins are chains of amino acids. An amino acid consists of a carbon atom bound to four groups. One is an amino group,NH2, and one is a carboxylic acid group,COOH although these exist as and under physiologic conditions. The third is a simple hydrogen atom. The fourth is commonly denoted and is different for each amino acid. There are twenty standard amino acids. Some of these have functions by themselves or in a modified form; for instance, glutamate functions as an important neurotransmitter. Generic amino acids in neutral form, as they exist physiologically, and joined together as a dipeptide.Amino acids can be joined together via a peptide bond. In this dehydration synthesis, a water molecule is removed and the peptide bond connects the nitrogen of one amino acid's amino group to the carbon of the other's carboxylic acid group. The resulting molecule is called a dipeptide, and short stretches of amino acids usually, fewer than around thirty are called peptides or polypeptides. Longer stretches merit the title proteins. As an example, the important blood serum protein albumin contains 585 amino acid residues.The structure of proteins is traditionally described in a hierarchy of four levels. The primary structure of a protein simply consists of its linear sequence of amino acids; for ,cinetryptophan-serineglutamate-asparagine-glycine-lysine.dary structure is concerned with local morphology. Some combinations of amino acids will tend to curl up in a coil called an a-helix or into a sheet called a ß-sheet; some a-helixes can be seen in the hemoglobin schematic above. Tertiary structure is the entire three-dimensional shape of the protein. This shape is determined by the sequence of amino acids. In fact, a single change can change the entire structure. The ß chain of hemoglobin contains 146 amino acid residues; substitution of the glutamate residue at position 6 with a valine residue changes the behavior of hemoglobin so much that it results in sickle-cell disease. Finally quaternary structure is concerned with the structure of a protein with multiple peptide subunits, like hemoglobin with its four subunits. Not all proteins have more than one subunit.Ingested proteins are usually broken up into single amino acids or dipeptides in the small intestine, and then absorbed. They can then be joined together to make new proteins. Intermediate products of glycolysis, the citric acid cycle, and the pentose phosphate pathway can be used to make all twenty amino acids, and most bacteria and plants possess all the necessary enzymes to synthesize them. Humans and other mammals, however, can only synthesize half of them. They cannot synthesize isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan, and valine. These are the essential amino acids, since it is essential to ingest them. Mammals do possess the enzymes to synthesize alanine, asparagine, aspartate, cysteine, glutamate, glutamine, glycine, proline, serine, and tyrosine, the nonessential amino acids. While they can synthesize arginine and histidine, they cannot produce it in sufficient amounts for young, growing animals, and so these are often considered essential amino acids.If the amino group is removed from an amino acid, it leaves behind a carbon skeleton called an a-keto acid. Enzymes called transaminases can easily transfer the amino group from one amino acid making it an a-keto acid to another a-keto acid making it an amino acid. This is important in the biosynthesis of amino acids, as for many of the pathways, intermediates from other biochemical pathways are converted to the a-keto acid skeleton, and then an amino group is added, often via transamination. The amino acids may then be linked together to make a protein.A similar process is used to break down proteins. It is first hydrolyzed into its component amino acids. Free ammonia NH3, existing as the ammonium ion NH4 in blood is toxic to life forms. A suitable method for excreting it must therefore exist. Different strategies have evolved in different animals, depending on the animals' needs. Unicellular organisms, of course, simply release the ammonia into the environment. Similarly, bony fish can release the ammonia into the water where it is quickly diluted. In general, mammals convert the ammonia into urea, via t
Biochemistry
Biochemistry Transformations
Biochemistry is the study of the chemical processes and transformations in living organisms. It deals with the structure and function of cellular components, such as proteins, carbohydrates, lipids, nucleic acids, and other biomolecules. Chemical biology aims to answer many questions arising from biochemistry by using tools developed within synthetic chemistry.Although there are a vast number of different biomolecules, many are complex and large molecules (called polymers) that are composed of similar repeating subunits (called monomers). Each class of polymeric biomolecule has a different set of subunit types. For example, a protein is a polymer made up of 40 or more amino acids. Biochemistry studies the chemical properties of important biological molecules, like proteins, in particular the chemistry of enzyme-catalyzed reactions. The biochemistry of cell metabolism and the endocrine system has been extensively described. Other areas of biochemistry include the genetic code, protein synthesis, cell membrane transport, and signal transduction.
Distribution of Terrestrial Biochemistry
This article only discusses terrestrial biochemistry (carbon- and water-based), as all the life forms we know are on Earth. Since life forms alive today are hypothesized by most to have descended from the same common ancestor, they would naturally have similar biochemistries, even for matters that seem to be essentially arbitrary, such as handedness of various biomolecules. It is unknown whether alternative biochemistries are possible or practical. Originally, it was generally believed that life was not subject to the laws of science the way non-life was. It was thought that only living beings could produce the molecules of life from other, previously existing biomolecules. Then, in 1828, Friedrich Wöhler published a paper about the synthesis of urea, proving that organic compounds can be created artificially. The dawn of biochemistry may have been the discovery of the first enzyme, diastase today called amylase), in 1833 by Anselme Payen. Eduard Buchner contributed the first demonstration of a complex biochemical process outside of a cell in 1896 alcoholic fermentation in cell extracts of yeast. Although the term “biochemistry” seems to have been first used in 1882, it is generally accepted that the formal coinage of biochemistry occurred in 1903 by Carl Neuberg, a German chemist. Previously, this area would have been referred to as physiological chemistry. Since then, biochemistry has advanced, especially since the mid-20th century, with the development of new techniques such as chromatography, X-ray diffraction, NMR spectroscopy, radioisotopic labeling, electron microscopy and molecular dynamics simulations. These techniques allowed for the discovery and detailed analysis of many molecules and metabolic pathways of the cell, such as glycolysis and the Krebs cycle citric acid cycle.Today, the findings of biochemistry are used in many areas, from genetics to molecular biology and from agriculture to medicine.
Carbohydrates&Monosaccharides
However, there are a lot of Type O blonds out there. If you find that the crime scene has footprints from a pair of Nike Air Jordans with a distinctive tread design and the suspect, in addition to being type O and blond, is also wearing Air Jordans with the same tread design, then you are much closer to linking the suspect with the crime scene. In this way, by accumulating bits of linking evidence in a chain, where each bit by itself isn't very strong but the set of all of them together is very strong, you can argue that your suspect really is the right person. With DNA, the same kind of thinking is used; you can look for matches based on sequence or on numbers of small repeating units of DNA sequence at a number of different locations on the person's genome; one or two even three aren't enough to be confident that the suspect is the right one, but four sometimes five are used and a match at all five is rare enough that you or a prosecutor or a jury can be very confident beyond a reasonable doubt that the right person is accused Experts point out that using DNA forensic technology is far superior to eyewitness accounts, where the odds for correct identification are about 50:50.The more probes used in DNA analysis, the greater the odds for a unique pattern and against a coincidental match, but each additional probe adds greatly to the time and expense of testing. Four to six probes are recommended. Testing with several more probes will become routine, observed John Hicks Alabama State Department of Forensic Services. He predicted that, DNA chip technology in which thousands of short DNA sequences are embedded in a tiny chip will enable much more rapid, inexpensive analysis using many more probes, and raising the odds against coincidental matches. RFLP is a technique for analyzing the variable lengths of DNA fragments that result from digesting a DNA sample with a special kind of enzyme.
Protein Synthesis
GlucoseThe simplest type of carbohydrate is a monosaccharide, which among other properties contains carbon, hydrogen, and oxygen, mostly in a ratio of 1:2:1 generalized formula CnH2nOn, where n is at least . Glucose, one of the most important carbohydrates, is an example of a monosaccharide. So is fructose, the sugar that gives fruits their sweet taste. Some carbohydratesespecially after condensation to oligo and polysaccharides contain less carbon relative to H and O, which still are present in ratio. Monosaccharides can be grouped into aldoses having an aldehyde group at the end of the chain, e. g. glucose and ketoses having a keto group in their chaine. Both aldoses and ketoses occur in an equilibrium between the open-chain forms and starting with chain lengths of C4 cyclic forms. These are generated by bond formation between one of the hydroxy groups of the sugar chain with the carbon of the aldehyde or keto group in a hemiacetal bond. This leads to saturated five membered in furanoses or six-membered in pyranoses heterocyclic rings containing one O as heteroatom. ordinary table sugar and probably the most familiar carbohydrate.Two monosaccharides can be joined together using dehydration synthesis, in which a hydrogen atom is removed from the end of one molecule and a hydroxyl group (OH) is removed from the other; the remaining residues are then attached at the sites from which the atoms were removed. The HOH or H2O is then released as a molecule of water, hence the term dehydration. The new molecule, consisting of two monosaccharides, is called a disaccharide and is conjoined together by a glycosidic or ether bond. The reverse reaction can also occur, using a molecule of water to split up a disaccharide and break the glycosidic bond; this is termed hydrolysis. The most well-known disaccharide is sucrose, ordinary sugar in scientific contexts, called table sugar or cane sugar to differentiate it from other sugars. Sucrose consists of a glucose molecule and a fructose molecule joined together. Another important disaccharide is lactose, consisting of a glucose molecule and a galactose molecule. As most humans age, the production of lactase, the enzyme that hydrolyzes lactose back into glucose and galactose, typically decreases. This results in lactase deficiency, also called lactose intolerance.Sugar polymers are characterised by having reducing or non-reducing ends. A reducing end of a carbohydrate is a carbon atom which can be in equilibrium with the open-chain aldehyde or keto form. If the joining of monomers takes place at such a carbon atom, the free hydroxy group of the pyranose or furanose form is exchanged with an OH-side chain of another sugar, yielding a full acetal. This prevents opening of the chain to the aldehyde or keto form and renders the modified residue non-reducing. Lactose contains a reducing end at its glucose moiety, whereas the galactose moiety form a full acetal with the C4-OH group of glucose. Saccharose does not have a reducing end because of full acetal formation between the aldehyde carbon of glucose and the keto carbon of fructos
Oligosaccharides and Polysaccharides
Cellulose as polymer of ß-D-glucoseWhen a few around three to six monosaccharides are joined together, it is called an oligosaccharide . These molecules tend to be used as markers and signals, as well as having some other uses.Many monosaccharides joined together make a polysaccharide. They can be joined together in one long linear chain, or they may be branched. Two of the most common polysaccharides are cellulose and glycogen, both consisting of repeating glucose monomers.Cellulose is made by plants and is an important structural component of their cell walls. Humans can neither manufacture nor digest it. Glycogen, on the other hand, is an animal carbohydrate; humans use it as a form of energy storag.Use of carbohydrates as an energy sourceSee also carbohydrate metabolism Glucose is the major energy source in most life forms. For instance, polysaccharides are broken down into their monomers glycogen phosphorylase removes glucose residues from glycogen Disaccharides like lactose or sucrose are cleaved into their two component monosaccharides. Glucose is mainly metabolized by a very important and ancient ten-step pathway called glycolysis, the net result of which is to break down one molecule of glucose into two molecules of pyruvate; this also produces a net two molecules of ATP, the energy currency of cells, along with two reducing equivalents in the form of converting NAD+ to NADH. This does not require oxygen; if no oxygen is available or the cell cannot use oxygen, the NAD is restored by converting the pyruvate to lactate or to ethanol plus carbon dioxide Other monosaccharides like galactose and fructose can be converted into intermediates of the glycolytic pathway.In aerobic cells with sufficient oxygen, like most human cells, the pyruvate is further metabolized. It is irreversibly converted to acetyl, giving off one carbon atom as the waste product carbon dioxide, generating another reducing equivalent as NADH. The two molecules acetyl-CoA from one molecule of glucosethen enter the citric acid cycle, producing two more molecules of ATP, six more NADH molecules and two reduced quinones via FADH2 as enzyme-bound cofactor, and releasing the remaining carbon atoms as carbon dioxide. The produced NADH and quinol molecules then feed into the enzyme complexes of the respiratory chain, an electron transport system transferring the electrons ultimately to oxygen and conserving the released energy in the form of a proton gradient over a membrane inner mitochondrial membrane in eukaryotes. Thereby, oxygen is reduced to water and the original electron acceptors NAD+ and quinone are regenerated. This is why humans breathe in oxygen and breathe out carbon dioxide. The energy released from transferring the electrons from high-energy states in NADH and quinol is conserved first as proton gradient and converted to ATP via ATP synthase. This generates an additional 28 molecules of ATP 24 from the 8 NADH + 4 from the 2 quinols, totaling to 32 molecules of ATP conserved per degraded glucose two from glycolysis two from the citrate cycle. It is clear that using oxygen to completely oxidize glucose provides an organism with far more energy than any oxygen-independent metabolic feature, and this is thought to be the reason why complex life appeared only after Earth's atmosphere accumulated large amounts of oxygen.
Gluconeogenesis & Proteins
In vertebrates, vigorously contracting skeletal muscles during weightlifting or sprinting, for example do not receive enough oxygen to meet the energy demand, and so they shift to anaerobic metabolism, converting glucose to lactate. The liver regenerates the glucose, using a process called gluconeogenesis. This process is not quite the opposite of glycolysis, and actually requires three times the amount of energy gained from glycolysis six molecules of ATP are used, compared to the two gained in glycolysis. Analogous to the above reactions, the glucose produced can then undergo glycolysis in tissues that need energy, be stored as glycogen starch in plants, or be converted to other monosaccharides or join A schematic of hemoglobin. The red and blue ribbons represent the protein globin; the green structures are the heme groups.Like carbohydrates, some proteins perform largely structural roles. For instance, movements of the proteins actin and myosin ultimately are responsible for the contraction of skeletal muscle. One property many proteins have is that they specifically bind to a certain molecule or class of molecules they may be extremely selective in what they bind. Antibodies are an example of proteins that attach to one specific type of molecule. In fact, the enzyme-linked immunosorbent assay (ELISA), which uses antibodies, is currently one of the most sensitive tests modern medicine uses to detect various biomolecules. Probably the most important proteins, however, are the enzymes. These amazing molecules recognize specific reactant molecules called substrates; they then catalyze the reaction between them. By lowering the activation energy, the enzyme speeds up that reaction by a rate of 1011 or more: a reaction that would normally take over 3,000 years to complete spontaneously might take less than a second with an enzyme. The enzyme itself is not used up in the process, and is free to catalyze the same reaction with a new set of substrates. Using various modifiers, the activity of the enzyme can be regulated, enabling control of the biochemistry of the cell as a whole.In essence, proteins are chains of amino acids. An amino acid consists of a carbon atom bound to four groups. One is an amino group,NH2, and one is a carboxylic acid group,COOH although these exist as and under physiologic conditions. The third is a simple hydrogen atom. The fourth is commonly denoted and is different for each amino acid. There are twenty standard amino acids. Some of these have functions by themselves or in a modified form; for instance, glutamate functions as an important neurotransmitter. Generic amino acids in neutral form, as they exist physiologically, and joined together as a dipeptide.Amino acids can be joined together via a peptide bond. In this dehydration synthesis, a water molecule is removed and the peptide bond connects the nitrogen of one amino acid's amino group to the carbon of the other's carboxylic acid group. The resulting molecule is called a dipeptide, and short stretches of amino acids usually, fewer than around thirty are called peptides or polypeptides. Longer stretches merit the title proteins. As an example, the important blood serum protein albumin contains 585 amino acid residues.The structure of proteins is traditionally described in a hierarchy of four levels. The primary structure of a protein simply consists of its linear sequence of amino acids; for ,cinetryptophan-serineglutamate-asparagine-glycine-lysine.dary structure is concerned with local morphology. Some combinations of amino acids will tend to curl up in a coil called an a-helix or into a sheet called a ß-sheet; some a-helixes can be seen in the hemoglobin schematic above. Tertiary structure is the entire three-dimensional shape of the protein. This shape is determined by the sequence of amino acids. In fact, a single change can change the entire structure. The ß chain of hemoglobin contains 146 amino acid residues; substitution of the glutamate residue at position 6 with a valine residue changes the behavior of hemoglobin so much that it results in sickle-cell disease. Finally quaternary structure is concerned with the structure of a protein with multiple peptide subunits, like hemoglobin with its four subunits. Not all proteins have more than one subunit.Ingested proteins are usually broken up into single amino acids or dipeptides in the small intestine, and then absorbed. They can then be joined together to make new proteins. Intermediate products of glycolysis, the citric acid cycle, and the pentose phosphate pathway can be used to make all twenty amino acids, and most bacteria and plants possess all the necessary enzymes to synthesize them. Humans and other mammals, however, can only synthesize half of them. They cannot synthesize isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan, and valine. These are the essential amino acids, since it is essential to ingest them. Mammals do possess the enzymes to synthesize alanine, asparagine, aspartate, cysteine, glutamate, glutamine, glycine, proline, serine, and tyrosine, the nonessential amino acids. While they can synthesize arginine and histidine, they cannot produce it in sufficient amounts for young, growing animals, and so these are often considered essential amino acids.If the amino group is removed from an amino acid, it leaves behind a carbon skeleton called an a-keto acid. Enzymes called transaminases can easily transfer the amino group from one amino acid making it an a-keto acid to another a-keto acid making it an amino acid. This is important in the biosynthesis of amino acids, as for many of the pathways, intermediates from other biochemical pathways are converted to the a-keto acid skeleton, and then an amino group is added, often via transamination. The amino acids may then be linked together to make a protein.A similar process is used to break down proteins. It is first hydrolyzed into its component amino acids. Free ammonia NH3, existing as the ammonium ion NH4 in blood is toxic to life forms. A suitable method for excreting it must therefore exist. Different strategies have evolved in different animals, depending on the animals' needs. Unicellular organisms, of course, simply release the ammonia into the environment. Similarly, bony fish can release the ammonia into the water where it is quickly diluted. In general, mammals convert the ammonia into urea, via t
Biochemistry is the study of the chemical processes and transformations in living organisms. It deals with the structure and function of cellular components, such as proteins, carbohydrates, lipids, nucleic acids, and other biomolecules. Chemical biology aims to answer many questions arising from biochemistry by using tools developed within synthetic chemistry.Although there are a vast number of different biomolecules, many are complex and large molecules (called polymers) that are composed of similar repeating subunits (called monomers). Each class of polymeric biomolecule has a different set of subunit types. For example, a protein is a polymer made up of 40 or more amino acids. Biochemistry studies the chemical properties of important biological molecules, like proteins, in particular the chemistry of enzyme-catalyzed reactions. The biochemistry of cell metabolism and the endocrine system has been extensively described. Other areas of biochemistry include the genetic code, protein synthesis, cell membrane transport, and signal transduction.
Distribution of Terrestrial Biochemistry
This article only discusses terrestrial biochemistry (carbon- and water-based), as all the life forms we know are on Earth. Since life forms alive today are hypothesized by most to have descended from the same common ancestor, they would naturally have similar biochemistries, even for matters that seem to be essentially arbitrary, such as handedness of various biomolecules. It is unknown whether alternative biochemistries are possible or practical. Originally, it was generally believed that life was not subject to the laws of science the way non-life was. It was thought that only living beings could produce the molecules of life from other, previously existing biomolecules. Then, in 1828, Friedrich Wöhler published a paper about the synthesis of urea, proving that organic compounds can be created artificially. The dawn of biochemistry may have been the discovery of the first enzyme, diastase today called amylase), in 1833 by Anselme Payen. Eduard Buchner contributed the first demonstration of a complex biochemical process outside of a cell in 1896 alcoholic fermentation in cell extracts of yeast. Although the term “biochemistry” seems to have been first used in 1882, it is generally accepted that the formal coinage of biochemistry occurred in 1903 by Carl Neuberg, a German chemist. Previously, this area would have been referred to as physiological chemistry. Since then, biochemistry has advanced, especially since the mid-20th century, with the development of new techniques such as chromatography, X-ray diffraction, NMR spectroscopy, radioisotopic labeling, electron microscopy and molecular dynamics simulations. These techniques allowed for the discovery and detailed analysis of many molecules and metabolic pathways of the cell, such as glycolysis and the Krebs cycle citric acid cycle.Today, the findings of biochemistry are used in many areas, from genetics to molecular biology and from agriculture to medicine.
Carbohydrates&Monosaccharides
However, there are a lot of Type O blonds out there. If you find that the crime scene has footprints from a pair of Nike Air Jordans with a distinctive tread design and the suspect, in addition to being type O and blond, is also wearing Air Jordans with the same tread design, then you are much closer to linking the suspect with the crime scene. In this way, by accumulating bits of linking evidence in a chain, where each bit by itself isn't very strong but the set of all of them together is very strong, you can argue that your suspect really is the right person. With DNA, the same kind of thinking is used; you can look for matches based on sequence or on numbers of small repeating units of DNA sequence at a number of different locations on the person's genome; one or two even three aren't enough to be confident that the suspect is the right one, but four sometimes five are used and a match at all five is rare enough that you or a prosecutor or a jury can be very confident beyond a reasonable doubt that the right person is accused Experts point out that using DNA forensic technology is far superior to eyewitness accounts, where the odds for correct identification are about 50:50.The more probes used in DNA analysis, the greater the odds for a unique pattern and against a coincidental match, but each additional probe adds greatly to the time and expense of testing. Four to six probes are recommended. Testing with several more probes will become routine, observed John Hicks Alabama State Department of Forensic Services. He predicted that, DNA chip technology in which thousands of short DNA sequences are embedded in a tiny chip will enable much more rapid, inexpensive analysis using many more probes, and raising the odds against coincidental matches. RFLP is a technique for analyzing the variable lengths of DNA fragments that result from digesting a DNA sample with a special kind of enzyme.
Protein Synthesis
GlucoseThe simplest type of carbohydrate is a monosaccharide, which among other properties contains carbon, hydrogen, and oxygen, mostly in a ratio of 1:2:1 generalized formula CnH2nOn, where n is at least . Glucose, one of the most important carbohydrates, is an example of a monosaccharide. So is fructose, the sugar that gives fruits their sweet taste. Some carbohydratesespecially after condensation to oligo and polysaccharides contain less carbon relative to H and O, which still are present in ratio. Monosaccharides can be grouped into aldoses having an aldehyde group at the end of the chain, e. g. glucose and ketoses having a keto group in their chaine. Both aldoses and ketoses occur in an equilibrium between the open-chain forms and starting with chain lengths of C4 cyclic forms. These are generated by bond formation between one of the hydroxy groups of the sugar chain with the carbon of the aldehyde or keto group in a hemiacetal bond. This leads to saturated five membered in furanoses or six-membered in pyranoses heterocyclic rings containing one O as heteroatom. ordinary table sugar and probably the most familiar carbohydrate.Two monosaccharides can be joined together using dehydration synthesis, in which a hydrogen atom is removed from the end of one molecule and a hydroxyl group (OH) is removed from the other; the remaining residues are then attached at the sites from which the atoms were removed. The HOH or H2O is then released as a molecule of water, hence the term dehydration. The new molecule, consisting of two monosaccharides, is called a disaccharide and is conjoined together by a glycosidic or ether bond. The reverse reaction can also occur, using a molecule of water to split up a disaccharide and break the glycosidic bond; this is termed hydrolysis. The most well-known disaccharide is sucrose, ordinary sugar in scientific contexts, called table sugar or cane sugar to differentiate it from other sugars. Sucrose consists of a glucose molecule and a fructose molecule joined together. Another important disaccharide is lactose, consisting of a glucose molecule and a galactose molecule. As most humans age, the production of lactase, the enzyme that hydrolyzes lactose back into glucose and galactose, typically decreases. This results in lactase deficiency, also called lactose intolerance.Sugar polymers are characterised by having reducing or non-reducing ends. A reducing end of a carbohydrate is a carbon atom which can be in equilibrium with the open-chain aldehyde or keto form. If the joining of monomers takes place at such a carbon atom, the free hydroxy group of the pyranose or furanose form is exchanged with an OH-side chain of another sugar, yielding a full acetal. This prevents opening of the chain to the aldehyde or keto form and renders the modified residue non-reducing. Lactose contains a reducing end at its glucose moiety, whereas the galactose moiety form a full acetal with the C4-OH group of glucose. Saccharose does not have a reducing end because of full acetal formation between the aldehyde carbon of glucose and the keto carbon of fructos
Oligosaccharides and Polysaccharides
Cellulose as polymer of ß-D-glucoseWhen a few around three to six monosaccharides are joined together, it is called an oligosaccharide . These molecules tend to be used as markers and signals, as well as having some other uses.Many monosaccharides joined together make a polysaccharide. They can be joined together in one long linear chain, or they may be branched. Two of the most common polysaccharides are cellulose and glycogen, both consisting of repeating glucose monomers.Cellulose is made by plants and is an important structural component of their cell walls. Humans can neither manufacture nor digest it. Glycogen, on the other hand, is an animal carbohydrate; humans use it as a form of energy storag.Use of carbohydrates as an energy sourceSee also carbohydrate metabolism Glucose is the major energy source in most life forms. For instance, polysaccharides are broken down into their monomers glycogen phosphorylase removes glucose residues from glycogen Disaccharides like lactose or sucrose are cleaved into their two component monosaccharides. Glucose is mainly metabolized by a very important and ancient ten-step pathway called glycolysis, the net result of which is to break down one molecule of glucose into two molecules of pyruvate; this also produces a net two molecules of ATP, the energy currency of cells, along with two reducing equivalents in the form of converting NAD+ to NADH. This does not require oxygen; if no oxygen is available or the cell cannot use oxygen, the NAD is restored by converting the pyruvate to lactate or to ethanol plus carbon dioxide Other monosaccharides like galactose and fructose can be converted into intermediates of the glycolytic pathway.In aerobic cells with sufficient oxygen, like most human cells, the pyruvate is further metabolized. It is irreversibly converted to acetyl, giving off one carbon atom as the waste product carbon dioxide, generating another reducing equivalent as NADH. The two molecules acetyl-CoA from one molecule of glucosethen enter the citric acid cycle, producing two more molecules of ATP, six more NADH molecules and two reduced quinones via FADH2 as enzyme-bound cofactor, and releasing the remaining carbon atoms as carbon dioxide. The produced NADH and quinol molecules then feed into the enzyme complexes of the respiratory chain, an electron transport system transferring the electrons ultimately to oxygen and conserving the released energy in the form of a proton gradient over a membrane inner mitochondrial membrane in eukaryotes. Thereby, oxygen is reduced to water and the original electron acceptors NAD+ and quinone are regenerated. This is why humans breathe in oxygen and breathe out carbon dioxide. The energy released from transferring the electrons from high-energy states in NADH and quinol is conserved first as proton gradient and converted to ATP via ATP synthase. This generates an additional 28 molecules of ATP 24 from the 8 NADH + 4 from the 2 quinols, totaling to 32 molecules of ATP conserved per degraded glucose two from glycolysis two from the citrate cycle. It is clear that using oxygen to completely oxidize glucose provides an organism with far more energy than any oxygen-independent metabolic feature, and this is thought to be the reason why complex life appeared only after Earth's atmosphere accumulated large amounts of oxygen.
Gluconeogenesis & Proteins
In vertebrates, vigorously contracting skeletal muscles during weightlifting or sprinting, for example do not receive enough oxygen to meet the energy demand, and so they shift to anaerobic metabolism, converting glucose to lactate. The liver regenerates the glucose, using a process called gluconeogenesis. This process is not quite the opposite of glycolysis, and actually requires three times the amount of energy gained from glycolysis six molecules of ATP are used, compared to the two gained in glycolysis. Analogous to the above reactions, the glucose produced can then undergo glycolysis in tissues that need energy, be stored as glycogen starch in plants, or be converted to other monosaccharides or join A schematic of hemoglobin. The red and blue ribbons represent the protein globin; the green structures are the heme groups.Like carbohydrates, some proteins perform largely structural roles. For instance, movements of the proteins actin and myosin ultimately are responsible for the contraction of skeletal muscle. One property many proteins have is that they specifically bind to a certain molecule or class of molecules they may be extremely selective in what they bind. Antibodies are an example of proteins that attach to one specific type of molecule. In fact, the enzyme-linked immunosorbent assay (ELISA), which uses antibodies, is currently one of the most sensitive tests modern medicine uses to detect various biomolecules. Probably the most important proteins, however, are the enzymes. These amazing molecules recognize specific reactant molecules called substrates; they then catalyze the reaction between them. By lowering the activation energy, the enzyme speeds up that reaction by a rate of 1011 or more: a reaction that would normally take over 3,000 years to complete spontaneously might take less than a second with an enzyme. The enzyme itself is not used up in the process, and is free to catalyze the same reaction with a new set of substrates. Using various modifiers, the activity of the enzyme can be regulated, enabling control of the biochemistry of the cell as a whole.In essence, proteins are chains of amino acids. An amino acid consists of a carbon atom bound to four groups. One is an amino group,NH2, and one is a carboxylic acid group,COOH although these exist as and under physiologic conditions. The third is a simple hydrogen atom. The fourth is commonly denoted and is different for each amino acid. There are twenty standard amino acids. Some of these have functions by themselves or in a modified form; for instance, glutamate functions as an important neurotransmitter. Generic amino acids in neutral form, as they exist physiologically, and joined together as a dipeptide.Amino acids can be joined together via a peptide bond. In this dehydration synthesis, a water molecule is removed and the peptide bond connects the nitrogen of one amino acid's amino group to the carbon of the other's carboxylic acid group. The resulting molecule is called a dipeptide, and short stretches of amino acids usually, fewer than around thirty are called peptides or polypeptides. Longer stretches merit the title proteins. As an example, the important blood serum protein albumin contains 585 amino acid residues.The structure of proteins is traditionally described in a hierarchy of four levels. The primary structure of a protein simply consists of its linear sequence of amino acids; for ,cinetryptophan-serineglutamate-asparagine-glycine-lysine.dary structure is concerned with local morphology. Some combinations of amino acids will tend to curl up in a coil called an a-helix or into a sheet called a ß-sheet; some a-helixes can be seen in the hemoglobin schematic above. Tertiary structure is the entire three-dimensional shape of the protein. This shape is determined by the sequence of amino acids. In fact, a single change can change the entire structure. The ß chain of hemoglobin contains 146 amino acid residues; substitution of the glutamate residue at position 6 with a valine residue changes the behavior of hemoglobin so much that it results in sickle-cell disease. Finally quaternary structure is concerned with the structure of a protein with multiple peptide subunits, like hemoglobin with its four subunits. Not all proteins have more than one subunit.Ingested proteins are usually broken up into single amino acids or dipeptides in the small intestine, and then absorbed. They can then be joined together to make new proteins. Intermediate products of glycolysis, the citric acid cycle, and the pentose phosphate pathway can be used to make all twenty amino acids, and most bacteria and plants possess all the necessary enzymes to synthesize them. Humans and other mammals, however, can only synthesize half of them. They cannot synthesize isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan, and valine. These are the essential amino acids, since it is essential to ingest them. Mammals do possess the enzymes to synthesize alanine, asparagine, aspartate, cysteine, glutamate, glutamine, glycine, proline, serine, and tyrosine, the nonessential amino acids. While they can synthesize arginine and histidine, they cannot produce it in sufficient amounts for young, growing animals, and so these are often considered essential amino acids.If the amino group is removed from an amino acid, it leaves behind a carbon skeleton called an a-keto acid. Enzymes called transaminases can easily transfer the amino group from one amino acid making it an a-keto acid to another a-keto acid making it an amino acid. This is important in the biosynthesis of amino acids, as for many of the pathways, intermediates from other biochemical pathways are converted to the a-keto acid skeleton, and then an amino group is added, often via transamination. The amino acids may then be linked together to make a protein.A similar process is used to break down proteins. It is first hydrolyzed into its component amino acids. Free ammonia NH3, existing as the ammonium ion NH4 in blood is toxic to life forms. A suitable method for excreting it must therefore exist. Different strategies have evolved in different animals, depending on the animals' needs. Unicellular organisms, of course, simply release the ammonia into the environment. Similarly, bony fish can release the ammonia into the water where it is quickly diluted. In general, mammals convert the ammonia into urea, via t
Saturday, January 26, 2008
seo
seo stands for search engine optimization.
Recently, after South Korea national football team's head coach Pim Verbeek resigned, along with his former national team teammate, best friend, and the current South Korea national football team's assistant coach Hong Myung-Bo was made on the list for the vacant head coaching job for the South Korea national football team.
Recently, after South Korea national football team's head coach Pim Verbeek resigned, along with his former national team teammate, best friend, and the current South Korea national football team's assistant coach Hong Myung-Bo was made on the list for the vacant head coaching job for the South Korea national football team.
Monday, January 21, 2008
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