What are the four stuctures of proteins???

Question

i kind of need it explained

Answer 1

Levels of protein structure

Protein structure, from primary to quaternary structure.Biochemists refer to four distinct aspects of a protein's structure:

Primary structure: the amino acid sequence of the peptide chains
Secondary structure: highly regular sub-structures--alpha helix and strands of beta sheet. Secondary structures are locally defined, meaning that there can be many different secondary motifs present in one single protein molecule
Tertiary structure: Three-dimensional structure of a single protein molecule; a spatial arrangement of the secondary structures
Quaternary structure: complex of several protein molecules or polypeptide chains, usually called protein subunits in this context, which function as part of the larger assembly or protein complex.
In addition to these levels of structure, proteins may shift between several similar structures in performing of their biological function. In the context of these functional rearrangements, these tertiary or quaternary structures are usually referred to as "conformations," and transitions between them are called conformational changes.

The primary structure is held together by covalent peptide bonds, which are made during the process of translation. The two ends of the amino acid chain are referred to as the carboxy terminus (C-terminus) and the amino terminus (N-terminus) based on the nature of the free group on each extremity.


[edit] Structure of the amino acids

An α-amino acidAn α-amino acid consists of a part, that is shared between all the amino acid types, and a side chain, that is unique to each type of residue. The Cα atom is bound to 4 different chemical (the H is omitted in the diagram), an amino group, a carboxyl group, a hydrogen and a side chain, specific for this type of amino acid. An exception from this rule is proline, where the hydrogen atom is replaced by a bond to the side chain. Because the carbon atom is bound to four different groups it is chiral, however only one of the isomers occur in biological proteins. Glycine however, is not chiral since its side chain is a hydrogen atom. A simple mnemonic for correct L-form is "CORN": when the Cα atom is viewed with the H in front, the residues read "CO-R-N" in a clockwise direction.


http://en.wikipedia.org/wiki/Protein_structure

Cruelty to Animals: Mechanized Madness

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The green pastures and idyllic barnyard scenes of years past are now distant memories. On today's factory farms, animals are crammed by the thousands into filthy windowless sheds, wire cages, gestation crates, and other confinement systems. These animals will never raise their families, root in the soil, build nests, or do anything that is natural to them. They won't even feel the sun on their backs or breathe fresh air until the day they are loaded onto trucks bound for slaughter.

Animals on today's factory farms have no legal protection from cruelty that would be illegal if it were inflicted on dogs or cats: neglect, mutilation, genetic manipulation, and drug regimens that cause chronic pain and crippling, transport through all weather extremes, and gruesome and violent slaughter. Yet farmed animals are no less intelligent or capable of feeling pain than are the dogs and cats we cherish as companions.

The factory farming system of modern agriculture strives to maximize output while minimizing costs. Cows, calves, pigs, chickens, turkeys, ducks, geese, and other animals are kept in small cages, in jam-packed sheds, or on filthy feedlots, often with so little space that they can't even turn around or lie down comfortably. They are deprived of exercise so that all their bodies' energy goes toward producing flesh, eggs, or milk for human consumption. The giant corporations that run most factory farms have found that they can make more money by cramming animals into tiny spaces, even though many of the animals get sick and some die. Industry journal National Hog Farmer explains, "Crowding Pigs Pays," and egg-industry expert Bernard Rollins writes that "chickens are cheap; cages are expensive."

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They are fed drugs to fatten them faster and to keep them alive in conditions that would otherwise kill them, and they are genetically altered to grow faster or to produce much more milk or eggs than they would naturally. Many animals become crippled under their own weight and die within inches of water and food.

While the suffering of all animals on factory farms is similar, each type of farmed animal faces different types of cruelty.
Chickens killed for their flesh in the United States are bred and drugged to grow so quickly that their hearts, lungs, and limbs often can't keep up. Read more about chickens.
Hens used for eggs live six or seven to a battery cage the size of a file drawer, thousands of which are stacked tier upon tier in huge, filthy warehouses. Read more about laying hens.
Cattle are castrated, their horns are ripped out of their heads, and third-degree burns (branding) are inflicted on them, all without any pain relief. Read more about cows raised for their flesh.
Factory Farming Photo Gallery
Cows used for their milk are drugged and bred to produce unnatural amounts of milk; they have their babies stolen from them shortly after birth and sent to notoriously cruel veal farms so that humans can drink the calves' milk. Read more about dairy cows.
Mother pigs on factory farms are confined to crates so small that they are unable to turn around or even lie down comfortably. Read more about pigs.
Fish on aquafarms spend their entire lives in cramped, filthy enclosures, and many suffer from parasitic infections, diseases, and debilitating injuries. Conditions on some farms are so horrendous that 40 percent of the fish may die before farmers can kill and package them for food. Read more about fish.
Turkeys' beaks and toes are burned off with a hot blade. Many suffer heart failure or debilitating leg pain, often becoming crippled under the weight of their genetically manipulated and drugged bodies. Read more about turkeys.
When they have finally grown large enough, animals raised for food are crowded onto trucks and transported over many miles through all weather extremes to the slaughterhouse. Those who survive this nightmarish journey will have their throats slit, often while they are still fully conscious. Many are still conscious when they are plunged into the scalding water of the defeathering or hair-removal tanks or while their bodies are being skinned or hacked apart

http://www.goveg.com/factoryFarming.asp

Answer 2

egg, chicken, beef and pork