Saturday, November 15, 2014
Friday, November 14, 2014
Ancient Aliens Mystery Continues
Friday, October 24, 2014
Diwali : The festival of lamp
Diwali also known as Deepavali and the "festival of lights", is an ancient Hindu festival celebrated in autumn every year. [ 5 ] [ 6 ]The festival spiritually signifies the victory of light over darkness, knowledge over ignorance, good over evil, and hope over despair. [ 7 ] [ 8 ] [ 9 ]The festival preparations and rituals typically extend over a five day period, but the main festival night of Diwali coincides with the darkest, new moon night of the Hindu Lunisolar month Kartika. In the Gregorian calendar, Diwali night falls between mid-October and mid-November.
Before Diwali night, people clean, renovate and decorate their homes and offices. [ 10 ]On Diwali night, Hindus dress up in new clothes or their best outfit, light up diyas(lamps and candles) inside and outside their home, participate in familypuja(prayers) typically to Lakshmi– the goddess of wealth and prosperity. Afterpuja, fireworks follow, [ 11 ]then a family feast includingmithai( sweets), and an exchange of gifts between family members and close friends. Diwali also marks a major shopping period in nations where it is celebrated. [ 12 ]
Diwali is an important festival for Hindus. The name of festive days as well as the rituals of Diwali vary significantly among Hindus, based on the region of India. In many parts of India, [ 13 ]the festivities start with Dhanteras, followed by Naraka Chaturdasion second day, Diwali on the third day,Diwali Padvadedicated to wife–husband relationship on the fourth day, and festivities end with Bhau-beejdedicated to sister–brother bond on the fifth day. Dhanterasusually falls eighteen days after Dussehra.
On the same night that Hindus celebrate Diwali, Jainscelebrate a festival of lights to mark the attainment of mokshaby Mahavira, [ 14 ] [ 15 ]and Sikhscelebrate Bandi Chhor Divas. [ 16 ]
Diwali is an official holiday in India, [ 17 ] Nepal, Sri Lanka, Myanmar, Mauritius, Guyana, Trinidad and Tobago, Suriname, Malaysia, Singaporeand Fiji.
Etymology
Diwali celebrations
Indoor Diyadecoration on Naraka Chaturdasinight
Outdoor Diya decoration on Diwali night
Diwali lanterns before Dhanterasin Maharashtra
A Nepalesetemple lighted up for Diwali
Official Bandi Chhor Divas celebrations in Amritsar
Diwali night fireworks over a city
Rural celebrations – floatingDiyaover river Ganges
DiwaliMithai( sweets)
Diwali festivities include a celebration of sights, sounds, arts and flavors. The festivities vary between different regions. [ 18 ] [ 19 ] [ 20 ]
Diwali is derived from the Sanskritfusion wordDīpāvali, formed fromdīpa(, "light" or "lamp" [ 21 ] [ 22 ]) andāvalī(, "series, line, row" [ 23 ]).DīpāvaliorDeepavalithus meant a "row" or "series of lights". [ 24 ]Tamil: ). Its celebration include millions of lights shining on housetops, outside doors and windows, around temples and other buildings in the communities and countries where it is observed. [ 18 ]
Diwali (Englishpronunciation: / d ɨ ˈ w ɑː l iː /) [ 5 ]is variously spelled or pronounced in diverse languages of India: 'deepabali' ( Oriya:), 'deepaboli' ( Bengali:), 'deepavali' ( Assamese:, Kannada:, Malayalam:and Telugu:), 'divali' ( Gujarati:, Hindi:, Marathi:, Konkani: Punjabi:), 'diyari' ( Sindhi:), and 'tihar' ( Nepali:).
Diwali also known as Deepavali and the "festival of lights", is an ancient Hindu festival celebrated in autumn every year. [ 5 ] [ 6 ]The festival spiritually signifies the victory of light over darkness, knowledge over ignorance, good over evil, and hope over despair. [ 7 ] [ 8 ] [ 9 ]The festival preparations and rituals typically extend over a five day period, but the main festival night of Diwali coincides with the darkest, new moon night of the Hindu Lunisolar month Kartika. In the Gregorian calendar, Diwali night falls between mid-October and mid-November.
Before Diwali night, people clean, renovate and decorate their homes and offices. [ 10 ]On Diwali night, Hindus dress up in new clothes or their best outfit, light up diyas(lamps and candles) inside and outside their home, participate in familypuja(prayers) typically to Lakshmi– the goddess of wealth and prosperity. Afterpuja, fireworks follow, [ 11 ]then a family feast includingmithai( sweets), and an exchange of gifts between family members and close friends. Diwali also marks a major shopping period in nations where it is celebrated. [ 12 ]
Diwali is an important festival for Hindus. The name of festive days as well as the rituals of Diwali vary significantly among Hindus, based on the region of India. In many parts of India, [ 13 ]the festivities start with Dhanteras, followed by Naraka Chaturdasion second day, Diwali on the third day,Diwali Padvadedicated to wife–husband relationship on the fourth day, and festivities end with Bhau-beejdedicated to sister–brother bond on the fifth day. Dhanterasusually falls eighteen days after Dussehra.
On the same night that Hindus celebrate Diwali, Jainscelebrate a festival of lights to mark the attainment of mokshaby Mahavira, [ 14 ] [ 15 ]and Sikhscelebrate Bandi Chhor Divas. [ 16 ]
Diwali is an official holiday in India, [ 17 ] Nepal, Sri Lanka, Myanmar, Mauritius, Guyana, Trinidad and Tobago, Suriname, Malaysia, Singaporeand Fiji.
Etymology
Diwali celebrations
Indoor Diyadecoration on Naraka Chaturdasinight
Outdoor Diya decoration on Diwali night
Diwali lanterns before Dhanterasin Maharashtra
A Nepalesetemple lighted up for Diwali
Official Bandi Chhor Divas celebrations in Amritsar
Diwali night fireworks over a city
Rural celebrations – floatingDiyaover river Ganges
DiwaliMithai( sweets)
Diwali festivities include a celebration of sights, sounds, arts and flavors. The festivities vary between different regions. [ 18 ] [ 19 ] [ 20 ]
Diwali is derived from the Sanskritfusion wordDīpāvali, formed fromdīpa(, "light" or "lamp" [ 21 ] [ 22 ]) andāvalī(, "series, line, row" [ 23 ]).DīpāvaliorDeepavalithus meant a "row" or "series of lights". [ 24 ]Tamil: ). Its celebration include millions of lights shining on housetops, outside doors and windows, around temples and other buildings in the communities and countries where it is observed. [ 18 ]
Diwali (Englishpronunciation: / d ɨ ˈ w ɑː l iː /) [ 5 ]is variously spelled or pronounced in diverse languages of India: 'deepabali' ( Oriya:), 'deepaboli' ( Bengali:), 'deepavali' ( Assamese:, Kannada:, Malayalam:and Telugu:), 'divali' ( Gujarati:, Hindi:, Marathi:, Konkani: Punjabi:), 'diyari' ( Sindhi:), and 'tihar' ( Nepali:).
Sunday, September 7, 2014
Sodium Oxide (Na2O)
SODIUM PEROXIDE (NA2O2)
Oxides of Potassium
Short Info : Magnesiun Oxide (MgO)
Calcium Oxide (CaO)
Sodium Hydroxide ( Caustic Soda ) NaOH
Potassium Hydroxide (KOH)
Calcium Hydroxide (Ca(OH)2)
Crossbred animals
Complete "Soil" guide part 1
Complete "Soil" guide part 2
Complete "Soil" guide part 3
Short note on : Air Pollution
Good Question : Why the copper wire used in an electromagnet is insulated ?
Simple Electric cell/ Voltas cell
Sodium peroxide
SODIUM PEROXIDE (Na2O2)
Preparation :
1. By heating the metal in excess of air or oxygen at 300', which is free from moisture and CO2.
2Na + O2 (excess) --> Na2O2
2. Industrial method : It is a two stage reaction in the presence of excess air.
2Na + O2 --> Na2O
Na2O + O2 --> Na2O2
Safety measures in using electricity.
Friday, July 25, 2014
The amazing dual behaviour of hydrogen.
HYDROGEN COMPOUNDS
Hydrogen in atomic form consist of one proton and one electron but , in elemental form it exists as a atomic ( H2 ) molecule . H2 is called as dihydrogen.
Position of hydrogen in the periodic table : Hydrogen is the first element of the periodic table as its atomic number is 1 . The single electron is present in the K shell i.e 1s1
The real growth in Neuroscience
Neuroscience is advancing rapidly. Nobody's questioning that. Brain-computer interfaces, optogenetics, transcranial magnetic stimulation—there's a lot of good stuff out there.
With respect to applications, a gaggle of neurotechnology startups are already starting to chip away at some curious corners of the medical technology space. But is the market ready? And more importantl y, is the science ready? This piece gives us some relatively concrete projection s on market readiness and financial/ scientific feasibility for a handful of emerging technologi es .
I'm a bit more conservat ive than the authors, though. Mainstrea m optogene tic implants in humans by 2026? Even if neuroscie nce does manage to wrangle $4.5 billion in extra funding over the next twelve years, I don't see this happenin g.
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Optogenetic implants in humans: The combination of genetic and optical methods to control specific events in targeted cells of living tissue, even within freely moving mammals and other animals, with the temporal precision (millisecond timescale) needed to keep pace with functioning intact biological systems.
Scientifically viable in 2021; mainstream and financially viable in 2026.
Really very hot stuff : Pepper
You know that tingling, numbing sensation you get from Sichuan peppers? It turns out that 'tingling' and 'numbing' might actually be the best way to describe it. A series of recent studies has shown that the relevant ingredient in the peppers targets neurons that respond to touch and vibration, thereby triggering the buzzing perception.
What's more is that evidence suggests we all feel those tingling vibrations at the same frequency. (It's around a low G.)
If only science was always this spicy.
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The task for the tingling volunteers was to try to match the peppery vibrations in their mouths to the vibrations they could feel in their fingertips as the researchers dialed the frequency of the box up or down — "They are closing their eyes and they're saying 'higher' or 'lower,' so it's kind of a bizarre situation," says Hagura — until the Sichuan buzz and the mechanical buzz converged on the same frequency, which turns out to be 50 hertz.Thursday, July 24, 2014
NASA X-43A 'Scramjet' Readied For Mach 10 Flight
NASA's high-risk, high-payoff Hyper-X Program is ready to attempt its greatest challenge yet - flying a "scramjet"-powered X-43A research vehicle at nearly 10 times the speed of sound.
Officials have set Nov. 15 or 16 for the flight, which will take place in restricted U.S. Naval airspace over the Pacific Ocean northwest of Los Angeles.
GaneshScience: s-BLOCK ELEMENTS
GaneshScience: s-BLOCK ELEMENTS: custom toolbar custom toolbar S.No. Atomic Properties Alkali metal 1. Outer electronic configuration ns^1 2. Oxidation nu...
Anti-Evolutionist s Need to Stop Talking About thermodynamics
The anti-evolutionists just never get tired of the second law thermodynamics! The latest bit of silliness comes from Barry Arrington, writing at Uncommon Descent. Here’s the whole post:
I hope our materialist friends will help us with this one.
As I understand their argument, entropy is not an obstacle to blind watchmaker evolution, because entropy applies absolutely only in a “closed system,” and the earth is not a closed system because it receives electromagnetic radiation from space.
Fair enough. But it seems to me that under that definition of “closed system” only the universe as a whole is a closed system, because every particular place in the universe receives energy of some kind from some other place. And if that is so, it seems the materialists have painted themselves into a corner in which they must, to remain logically consistent, assert that entropy applies everywhere but no place in particular, which is absurd.
Now this seems like an obvious objection, and if it were valid the “closed system/open system” argument would have never gained any traction to begin with. So I hope someone will clue me in as to what I am missing.
I think Arrington is missing quite a lot, actually.
Let’s start with the obvious. Many physical laws and theories only strictly apply to idealized scenarios, but that does not stop them from being very useful. There are no ideal gases in nature, but we have an ideal gas law that tells us how they behave. Physical objects never engage in perfectly elastic collisions, but classical mechanics tells us quite a lot about what would happen if they did. Heck, there are no triangles in nature, but trigonometry is still fantastically useful stuff.
So, yes, the only truly closed system is the universe as a whole, a fact pointed out in virtually every book on thermodynamics. But there are many systems that are close enough to closed for practical purposes, and that is enough to make the second law very useful indeed.
(Incidentally, for the purposes of this post I won’t belabor the distinction between a closed system and an isolated system. The former refers to one where no mass is crossing the system’s boundary, while the latter requires that neither matter nor energy is crossing the boundary. If you are making the statement, “Entropy cannot spontaneously decrease,” then you had better be talking about an isolated system. While we’re at it, for the purposes of this post I will be discussing everything in the context of classical thermodynamics. I will not discuss statistical mechanics or anything like that.)
The bigger thing that Arrington is missing, however, is that there is so much more to the second law than the statement that entropy cannot decrease in an isolated system.
One frustration in learning about thermodynamics is that you can consult a multitude of textbooks and popularizations and never find the second law stated the same way twice. Sometimes it is boiled down to the simple statement that heat always travels from a hot body to a cooler body. Sometimes it is expressed in terms of heat engines. Sometimes it is presented with an impenetrable amount of mathematics. Making things worse is that it is very hard to pin down what, precisely, entropy is. That’s why you get a lot of talk about complexity, or randomness, or useful energy, in popularizations of this topic. These ideas capture some of the spirit of the concept, but they also fool a lot of people into thinking they know what they are talking about.
When creationists first noticed that the second law could be used to rhetorical advantage, they tended to do so in a shockingly naïve way. For example, here’s Henry Morris, from his bookThe Troubled Waters of Evolution:
Evolutionists have fostered the strange belief that everything is involved in a process of progress, from chaotic particles billions of years ago all the way up to complex people today. The fact is, the most certain laws of science state that the real processes of nature do not make things go uphill, but downhill. Evolution is impossible!
And later:
There is … firm evidence that evolution never could take place.The law of increasing entropyis an impenetrable barrier which no evolutionary mechanism yet suggested has ever been able to overcome. Evolution and entropy are opposing and mutually exclusive concepts. If the entropy principle is really a universal law, then evolution must be impossible.
Now, when creationists are saying things likethat, it is perfectly reasonable to emphasize in reply that the second law only precludes spontaneous decreases in entropy in isolated systems, which the Earth certainly is not. But that statement is hardly the entirety of what physicists know about entropy.
To fully understand the magnitude of what Arrington is missing, we should consider what the second law was accomplishes. The principles of thermodynamics make certain claims about what sorts of processes are physically possible.
Super-sniffing elephants
Super-sniffing elephants
Feral Cats as Invasive Species
The ranger stood on the dirt road, facing south, and the rest of us, scattered about the parked safari truck, facing north and paying close attention to what she was saying. The sun was slipping quickly below the red sand dunes to our west, and the day’s warm breeze was rapidly changing to a chill wind. She talked about what we might see after we remounted the safari truck, which we had just driven out of the campground at the southern end of Kgalgadi Transfrontier Park, where we were staying in the South African camp, just across from the Botswana camp. This would be a night drive, cold, dark, uncomfortable seats, loud engine in the giant 26-seater truck, scanning the brush and the roadside with three or four strong spotlights wrangled by volunteers among the nature-loving tourists, and of course, the headlights of the truck. But for now the sun was still up and if anything interesting came along we’d see it just fine in the dusk.
And, of course, something interesting came along. Just as the ranger was telling us that we might see wild cats – well, not wild cats, but rather, Wildcats, the wild version of the domestic cat, Felis silvestris lybica, one of those cats popped its head out of the brush about 50 feet beyond her. As she continued her monologue about these cats, the Wildcat cautiously walked in our direction, never taking its eyes off of us, stiff-legged, ears motionless, striped like a standard “tiger” domestic cat but entirely in grays. The most interesting thing about this cat was lack of kitty-cat-ness. It was not a kitty cat, even though all of its relatives in the Americas were. It was deadly serious, intense looking, nothing like a kitty cat at all. And just as the ranger finished her monologue with “… so if we’re lucky, we’ll see one of those cats” the person standing next to me intoned, in a mimicking fake british-sounding accent to match the ranger’s South African dialect, “You mean like that one, there?” and all of us pointed simultaneously to the wildcat now about 10 feet behind her.
She turned, looked, and by the expression on her face I guessed she was thinking “Goodness, I’m glad that was not a lion.”
Protein : Other info
Methods of study
Main article: Protein methods
The activities and structures of proteins may be examined in vitro, in vivo, and in silico.In vitrostudies of purified proteins in controlled environments are useful for learning how a protein carries out its function: for example, enzyme kineticsstudies explore the chemical mechanismof an enzyme's catalytic activity and its relative affinity for various possible substrate molecules. By contrast,in vivoexperiments can provide information about the physiological role of a protein in the context of a cellor even a whole organism.In silicostudies use computational methods to study proteins.
Protein purification
Main article: Protein purification
To perform in vitroanalysis, a protein must be purified away from other cellular components. This process usually begins with cell lysis, in which a cell's membrane is disrupted and its internal contents released into a solution known as a crude lysate. The resulting mixture can be purified using ultracentrifugation, which fractionates the various cellular components into fractions containing soluble proteins; membrane lipidsand proteins; cellular organelles, and nucleic acids. Precipitationby a method known as salting outcan concentrate the proteins from this lysate. Various types of chromatographyare then used to isolate the protein or proteins of interest based on properties such as molecular weight, net charge and binding affinity. [ 38 ]The level of purification can be monitored using various types of gel electrophoresisif the desired protein's molecular weight and isoelectric pointare known, by spectroscopyif the protein has distinguishable spectroscopic features, or by enzyme assaysif the protein has enzymatic activity. Additionally, proteins can be isolated according their charge using electrofocusing. [ 39 ]
For natural proteins, a series of purification steps may be necessary to obtain protein sufficiently pure for laboratory applications. To simplify this process, genetic engineeringis often used to add chemical features to proteins that make them easier to purify without affecting their structure or activity. Here, a "tag" consisting of a specific amino acid sequence, often a series of histidineresidues (a " His-tag"), is attached to one terminus of the protein. As a result, when the lysate is passed over a chromatography column containing nickel, the histidine residues ligate the nickel and attach to the column while the untagged components of the lysate pass unimpeded. A number of different tags have been developed to help researchers purify specific proteins from complex mixtures. [ 40 ]
Cellular localization
Proteins in different cellular compartmentsand structures tagged with green fluorescent protein(here, white)
The study of proteinsin vivois often concerned with the synthesis and localization of the protein within the cell. Although many intracellular proteins are synthesized in the cytoplasmand membrane-bound or secreted proteins in the endoplasmic reticulum, the specifics of how proteins are targetedto specific organelles or cellular structures is often unclear. A useful technique for assessing cellular localization uses genetic engineering to express in a cell a fusion proteinor chimeraconsisting of the natural protein of interest linked to a " reporter" such as green fluorescent protein(GFP). [ 41 ]The fused protein's position within the cell can be cleanly and efficiently visualized using microscopy, [ 42 ]as shown in the figure opposite.
Other methods for elucidating the cellular location of proteins requires the use of known compartmental markers for regions such as the ER, the Golgi, lysosomes or vacuoles, mitochondria, chloroplasts, plasma membrane, etc. With the use of fluorescently tagged versions of these markers or of antibodies to known markers, it becomes much simpler to identify the localization of a protein of interest. For example, indirect immunofluorescencewill allow for fluorescence colocalization and demonstration of location. Fluorescent dyes are used to label cellular compartments for a similar purpose. [ 43 ]
Other possibilities exist, as well. For example, immunohistochemistryusually utilizes an antibody to one or more proteins of interest that are conjugated to enzymes yielding either luminescent or chromogenic signals that can be compared between samples, allowing for localization information. Another applicable technique is cofractionation in sucrose (or other material) gradients using isopycnic centrifugation. [ 44 ]While this technique does not prove colocalization of a compartment of known density and the protein of interest, it does increase the likelihood, and is more amenable to large-scale studies.
Finally, the gold-standard method of cellular localization is immunoelectron microscopy. This technique also uses an antibody to the protein of interest, along with classical electron microscopy techniques.
Structural protein
Structural proteins
Structural proteins confer stiffness and rigidity to otherwise-fluid biological components. Most structural proteins are fibrous proteins; for example, collagenand elastinare critical components of connective tissuesuch as cartilage, and keratinis found in hard or filamentous structures such as hair, nails, feathers, hooves, and some animal shells. [ 36 ]Some globular proteinscan also play structural functions, for example, actinand tubulinare globular and soluble as monomers, but polymerizeto form long, stiff fibers that make up the cytoskeleton, which allows the cell to maintain its shape and size.
Other proteins that serve structural functions are motor proteinssuch as myosin, kinesin, and dynein, which are capable of generating mechanical forces. These proteins are crucial for cellular motilityof single celled organisms and the spermof many multicellular organisms which reproduce sexually. They also generate the forces exerted by contracting muscles [ 37 ]and play essential roles in intracellular transport.
Main Role of protein in body.
Types of synthesis : 2. Chemical synthesis
Chemical synthesis
Short proteins can also be synthesized chemically by a family of methods known as peptide synthesis, which rely on organic synthesistechniques such as chemical ligationto produce peptides in high yield. [ 9 ]Chemical synthesis allows for the introduction of non-natural amino acids into polypeptide chains, such as attachment of fluorescentprobes to amino acid side chains. [ 10 ]These methods are useful in laboratory biochemistryand cell biology, though generally not for commercial applications. Chemical synthesis is inefficient for polypeptides longer than about 300 amino acids, and the synthesized proteins may not readily assume their native tertiary structure. Most chemical synthesis methods proceed from C-terminus to N-terminus, opposite the biological reaction. [ 11 ]
Structure
Main article: Protein structure
Further information: Protein structure prediction
The crystal structure of the chaperonin. Chaperonins assist protein folding.
Three possible representations of the three-dimensional structure of the protein triose phosphate isomerase. Left: all-atom representation colored by atom type. Middle: Simplified representation illustrating the backbone conformation, colored by secondary structure. Right: Solvent-accessible surface representation colored by residue type (acidic residues red, basic residues blue, polar residues green, nonpolar residues white)
Most proteins foldinto unique 3-dimensional structures. The shape into which a protein naturally folds is known as its native conformation. [ 12 ]Although many proteins can fold unassisted, simply through the chemical properties of their amino acids, others require the aid of molecular chaperonesto fold into their native states. [ 13 ]Biochemists often refer to four distinct aspects of a protein's structure: [ 14 ]
*. Primary structure: the amino acid sequence. A protein is a polyamide.
*. Secondary structure: regularly repeating local structures stabilized by hydrogen bonds. The most common examples are the alpha helix, beta sheetand turns. Because secondary structures are local, many regions of different secondary structure can be present in the same protein molecule.
*. Tertiary structure: the overall shape of a single protein molecule; the spatial relationship of the secondary structures to one another. Tertiary structure is generally stabilized by nonlocal interactions, most commonly the formation of a hydrophobic core, but also through salt bridges, hydrogen bonds, disulfide bonds, and even posttranslational modifications. The term "tertiary structure" is often used as synonymous with the termfold. The tertiary structure is what controls the basic function of the protein.
*. Quaternary structure: the structure formed by several protein molecules (polypeptide chains), usually called protein subunitsin this context, which function as a single protein complex.
Proteins are not entirely rigid molecules. In addition to these levels of structure, proteins may shift between several related structures while they perform their functions. In the context of these functional rearrangements, these tertiary or quaternary structures are usually referred to as " conformations", and transitions between them are calledconformational changes.Such changes are often induced by the binding of a substratemolecule to an enzyme's active site, or the physical region of the protein that participates in chemical catalysis. In solution proteins also undergo variation in structure through thermal vibration and the collision with other molecules. [ 15 ]
Molecular surface of several proteins showing their comparative sizes. From left to right are: immunoglobulin G(IgG, an antibody), hemoglobin, insulin(a hormone), adenylate kinase(an enzyme), and glutamine synthetase(an enzyme).
Proteins can be informally divided into three main classes, which correlate with typical tertiary structures: globular proteins, fibrous proteins, and membrane proteins. Almost all globular proteins are solubleand many are enzymes. Fibrous proteins are often structural, such as collagen, the major component of connective tissue, or keratin, the protein component of hair and nails. Membrane proteins often serve as receptorsor provide channels for polar or charged molecules to pass through the cell membrane. [ 16 ]
A special case of intramolecular hydrogen bonds within proteins, poorly shielded from water attack and hence promoting their own dehydration, are called dehydrons.
Types of Protein synthesis 1) Biosynthesis
Synthesis
Biosynthesis
Main article: Protein biosynthesis
A ribosome produces a protein using mRNA as template.
The DNAsequence of a gene encodesthe amino acidsequence of a protein.
Proteins are assembled from amino acids using information encoded in genes. Each protein has its own unique amino acid sequence that is specified by the nucleotidesequence of the gene encoding this protein. The genetic codeis a set of three-nucleotide sets called codonsand each three-nucleotide combination designates an amino acid, for example AUG ( adenine- uracil- guanine) is the code for methionine. Because DNAcontains four nucleotides, the total number of possible codons is 64; hence, there is some redundancy in the genetic code, with some amino acids specified by more than one codon. [ 6 ]Genes encoded in DNA are first transcribedinto pre- messenger RNA(mRNA) by proteins such as RNA polymerase. Most organisms then process the pre-mRNA (also known as aprimary transcript) using various forms of Post-transcriptional modificationto form the mature mRNA, which is then used as a template for protein synthesis by the ribosome. In prokaryotesthe mRNA may either be used as soon as it is produced, or be bound by a ribosome after having moved away from the nucleoid. In contrast, eukaryotesmake mRNA in the cell nucleusand then translocateit across the nuclear membraneinto the cytoplasm, where protein synthesisthen takes place. The rate of protein synthesis is higher in prokaryotes than eukaryotes and can reach up to 20 amino acids per second. [ 7 ]
The process of synthesizing a protein from an mRNA template is known as translation. The mRNA is loaded onto the ribosome and is read three nucleotides at a time by matching each codon to its base pairing anticodonlocated on a transfer RNAmolecule, which carries the amino acid corresponding to the codon it recognizes. The enzyme aminoacyl tRNA synthetase"charges" the tRNA molecules with the correct amino acids. The growing polypeptide is often termed thenascent chain. Proteins are always biosynthesized from N-terminusto C-terminus. [ 6 ]
The size of a synthesized protein can be measured by the number of amino acids it contains and by its total molecular mass, which is normally reported in units ofdaltons(synonymous with atomic mass units), or the derivative unit kilodalton (kDa). Yeastproteins are on average 466 amino acids long and 53 kDa in mass. [ 5 ]The largest known proteins are the titins, a component of the muscle sarcomere, with a molecular mass of almost 3,000 kDa and a total length of almost 27,000 amino acids.
Biochemestry protein : Most interesting topic of the day
Most proteins consist of linear polymersbuilt from series of up to 20 differentL-α- amino acids. All proteinogenic amino acidspossess common structural features, including an α-carbonto which an aminogroup, a carboxylgroup, and a variable side chainare bonded. Only prolinediffers from this basic structure as it contains an unusual ring to the N-end amine group, which forces the CO–NH amide moiety into a fixed conformation. [ 1 ]The side chains of the standard amino acids, detailed in the list of standard amino acids, have a great variety of chemical structures and properties; it is the combined effect of all of the amino acid side chains in a protein that ultimately determines its three-dimensional structure and its chemical reactivity. [ 2 ]The amino acidsin a polypeptide chain are linked by peptide bonds. Once linked in the protein chain, an individual amino acid is called aresidue,and the linked series of carbon, nitrogen, and oxygen atoms are known as themain chainorprotein backbone. [ 3 ]
The peptide bond has two resonanceforms that contribute some double-bondcharacter and inhibit rotation around its axis, so that the alpha carbons are roughly coplanar. The other two dihedral anglesin the peptide bond determine the local shape assumed by the protein backbone. [ 4 ]The end of the protein with a free carboxyl group is known as the C-terminusor carboxy terminus, whereas the end with a free amino group is known as the N-terminusor amino terminus. The wordsprotein,polypeptide,and peptideare a little ambiguous and can overlap in meaning.Proteinis generally used to refer to the complete biological molecule in a stable conformation, whereaspeptideis generally reserved for a short amino acid oligomers often lacking a stable three-dimensional structure. However, the boundary between the two is not well defined and usually lies near 20–30 residues. [ 5 ]Polypeptidecan refer to any single linear chain of amino acids, usually regardless of length, but often implies an absence of a defined conformation.
Protein
Proteins( / ˈ p r oʊ ˌ t iː n z /or / ˈ p r oʊ t i . ɨ n z /) are large biological molecules, or macromolecules, consisting of one or more long chains of amino acid residues. Proteins perform a vast array of functions within living organisms, including catalyzing metabolic reactions, replicating DNA, responding to stimuli, and transporting molecules from one location to another. Proteins differ from one another primarily in their sequence of amino acids, which is dictated by the nucleotide sequenceof their genes, and which usually results in foldingof the protein into a specific three- dimensional structurethat determines its activity.
A linear chain of amino acid residues is called a polypeptide. A protein contains at least one long polypeptide. Short polypeptides, containing less than about 20-30 residues, are rarely considered to be proteins and are commonly called peptides, or sometimes oligopeptides. The individual amino acid residues are bonded together by peptide bondsand adjacent amino acid residues. The sequenceof amino acid residues in a protein is defined by the sequenceof a gene, which is encoded in the genetic code. In general, the genetic code specifies 20 standard amino acids; however, in certain organisms the genetic code can include selenocysteineand—in certain archaea— pyrrolysine. Shortly after or even during synthesis, the residues in a protein are often chemically modified by posttranslational modification, which alters the physical and chemical properties, folding, stability, activity, and ultimately, the function of the proteins. Sometimes proteins have non-peptide groups attached, which can be called prosthetic groupsor cofactors. Proteins can also work together to achieve a particular function, and they often associate to form stable protein complexes.
Once formed, proteins only exist for a certain period of time and are then degradedand recycled by the cell's machinery through the process of protein turnover. A protein's lifespan is measured in terms of its half-lifeand covers a wide range. They can exist for minutes or years with an average lifespan of 1-2 days in mammalian cells. Abnormal and or misfolded proteins are degraded more rapidly either due to being targeted for destruction or due to being unstable.
Like other biological macromoleculessuch as polysaccharidesand nucleic acids, proteins are essential parts of organisms and participate in virtually every process within cells. Many proteins are enzymesthat catalyzebiochemical reactions and are vital to metabolism. Proteins also have structural or mechanical functions, such as actinand myosinin muscle and the proteins in the cytoskeleton, which form a system of scaffoldingthat maintains cell shape. Other proteins are important in cell signaling, immune responses, cell adhesion, and the cell cycle. Proteins are also necessary in animals' diets, since animals cannot synthesizeall the amino acids they need and must obtain essential amino acidsfrom food. Through the process of digestion, animals break down ingested protein into free amino acids that are then used in metabolism.
Proteins may be purifiedfrom other cellular components using a variety of techniques such as ultracentrifugation, precipitation, electrophoresis, and chromatography; the advent of genetic engineeringhas made possible a number of methods to facilitate purification. Methods commonly used to study protein structure and function include immunohistochemistry, site-directed mutagenesis, X-ray crystallography, nuclear magnetic resonanceand mass spectrometry.
Atmospheric Pressure
CONVERVATION OF BIODIVERSITY AND ENVIRONMENT
Biological diversity.
Tissue Culture
Tissue Culture
STARS AND OUR SOLAR SYSTEM
CO2 (Carbon Dioxide) for Good Use.
Soil Pollution
Microbial fuel cell new
Amicrobial fuel cell(MFC) orbiological fuel cellis a bio- electrochemicalsystem that drives a currentby usingbacteria and mimicki ... bacteriaand mimicking bacterial interactions found in nature. MFCs can be grouped into two general categories, those that use a mediator and those that are mediator-less. The first MFCs, demonstrated in the early 20th century, used a mediator: a chemical that transfers electrons from the bacteria in the cell to the anode. Mediator-less MFCs are a more recent development dating to the 1970s; in this type of MFC the bacteria typically have electrochemically active redox proteinssuch as cytochromeson their outer membrane that can transfer electrons directly to the anode. [ 1 ]Since the turn of the 21st century MFCs have started to find a commercial use in the treatment of wastewater. [ 2 ]
History
The idea of using microbial cells in an attempt to produce electricitywas first conceived in the early twentieth century. M. Potter was the first to perform work on the subject in 1911. [ 3 ]A professor of botany at the University of Durham, Potter managed to generate electricity from E. coli, but the work was not to receive any major coverage. In 1931, however, Barnet Cohen drew more attention to the area when he created a number of microbial half fuel cells that, when connected in series, were capable of producing over 35 volts, though only with a current of 2 milliamps. [ 4 ]
More work on the subject came with a study by DelDuca et al. who used hydrogen produced by the fermentationof glucose by Clostridium butyricumas the reactant at the anode of a hydrogen and air fuel cell. Though the cell functioned, it was found to be unreliable owing to the unstable nature of hydrogen production by the micro-organisms. [ 5 ]Although this issue was later resolved in work by Suzuki et al. in 1976 [ 6 ]the current design concept of an MFC came into existence a year later with work once again by Suzuki. [ 7 ]
By the time of Suzuki’s work in the late 1970s, little was understood about how microbial fuel cells functioned; however, the idea was picked up and studied later in more detail first by MJ Allen and then later by H. Peter Bennetto both from King's College London. People saw the fuel cell as a possible method for the generation of electricity for developing countries. His work, starting in the early 1980s, helped build an understanding of how fuel cells operate, and until his retirement, he was seen by many[ who?]as the foremost authority on the subject.
It is now known that electricity can be produced directly from the degradation of organic matter in a microbial fuel cell. Like a normal fuel cell, an MFC has both an anode and a cathode chamber. The anoxicanode chamber is connected internally to the cathode chamber via an ion exchange membrane with the circuit completed by an external wire.
In May 2007, the University of Queensland, Australia completed its prototype MFC as a cooperative effort with Foster's Brewing. The prototype, a 10 L design, converts brewery wastewaterinto carbon dioxide, clean water, and electricity. With the prototype proven successful[ citation needed], plans are in effect to produce a 660 gallon version for the brewery, which is estimated to produce 2 kilowatts of power. While this is a small amount of power, the production of clean water is of utmost importance to Australia, for which droughtis a constant threat.
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