An Account of Proteins and Their Structure It is difficult to describe in a simple sentence the role of proteins. Let's say: When there is something to do, it is a protein that does it. Some examples of proteins * Antibodies: they recognize molecules of invading organisms. * Receptors: part of the cell membrane, they recognize other proteins, or chemicals, and inform the cell. * Enzymes: assemble or digest. The role (or function) of a protein depends on its shape, and chemical formula. Proteins play a number of vital roles in all organisms. Unlike carbohydrates and lipids they always contain nitrogen as well as carbon, hydrogen and oxygen. Sulphuris often present. The building blocks of the proteins are amino acids. Proteins are made of a long chain of amino acids, sometimes modified by the addition of sugars and phosphates. Amino acids unite to form proteins in much the same manner the monosaccharides combine to form polysaccharides, and fatty acids and glycerol combine to form fats and oils. This happens when two amino acids reacts. The reaction occurs between the amino group of one amino acid and the carboxyl group of another. To make this happen a condensation reaction has to occur which involves the removal of a molecule of water. Once this happens two amino acids become joined by a peptide link to form a dipeptide. To form a polypeptide a series of condensation reactions must happen which forms a longer chain. The individuality of a particular protein is determined by the sequence of amino acids comprising its polypeptide chains, together with the pattern of folding and cross-linkages. ... ... middle of paper ... ...rs, nails, hooves and horns. Collagen is another fibrous protein. It is the most abundant protein in vertebrates, making up a third of their total protein mass. The human body is mainly held together by collagen as it is found in bones, cartilage, tendons, ligaments, connective tissue and skin. Collagen fibres have a tensile strength greater than steel which makes it very strong. Careful analysis of collagen had shown that they consist of three polypeptide chains coiled round each other in a triple helix. The resulting structure is like a plaited rope and has great strength. In conclusion proteins are probably the most important class of biochemical molecules, although of course lipids and carbohydrates are also essential for life. Proteins are the basis for the major structural components of animal and human tissue.
The shape of the protein chains that produce the building blocks and other structures used in life is mostly determined by weak chemical bonds that are easily broken and remade. These chains can shorten, lengthen, and change shape in response to the input or withdrawal of energy. The changes in the chains alter the shape of the protein and can also alter its function or cause it to become either active or inactive. The ATP molecule can bond to one part of a... ... middle of paper ... ...
The primary structure is the sequence of amino acids that make up a polypeptide chain. 20 different amino acids are found in proteins. The exact order of the amino acids in a specific protein is the primary sequence for that protein. [IMAGE] [IMAGE]Protein secondary structure refers to regular, repeated patterns of folding of the protein backbone. The two most common folding patterns are the alpha helix and the beta sheet.
In the subsequent essay I will discuss and explain the relative function of the Prion protein. The Prion protein, also known as PrPC, ‘’is a membrane-anchored protein with two N-glycosylation sites and, although it is highly expressed in the nervous tissues, its physiological functions have yet to be well established’’ (Coordination Chemistry Reviews). PrPC/PrP is found in healthy brains in this form, and consists of 250 Amino Acids, yet after a simple misfolding in the secondary structure; this can alienate the PrP and forms PrPsc, which is the abnormal form of the Prion protein. The infectious agent PrPsc causes neuropathological changes in the brain, and instantly places the individual under the category of someone with the prion disease. PrPsc forms insoluble fibres and thus cannot be studied well using Nuclear Mass Resonance (NMR), and it is also more resistant to protease digestion. Furthermore, ‘’ The transmissible spongiform encephalopathies (TSEs) arise from conversion of the membrane-bound prion protein from PrPC to PrPSc, the latter being the scrapie form. Examples of the TSEs include mad cow disease, chronic wasting disease in deer and elk, scrapie in goats and sheep, and kuru and Creutzfeldt-Jakob disease in humans’’ (http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2904554/. 2014). The following diagram shows the conversion from PrPc to PrPsc:
Proteins are one of the main building blocks of the body. They are required for the structure, function, and regulation of the body’s tissues and organs. Even smaller units create proteins; these are called amino acids. There are twenty different types of amino acids, and all twenty are configured in many different chains and sequences, producing differing protein structures and functions. An enzyme is a specialized protein that participates in chemical reactions where they serve as catalysts to speed up said reactions, or reduce the energy of activation, noted as Ea (Mader & Windelspecht).
The mitochondria has an eggshape structure. The mitochondria consists of an inner and outer membrane. The outer membrane is what shapes the organelle to its egglike shape. The inner membrane which folds inward makes a set of "shelves" or cristae that allow the reactions of the mitochondria to take place. The more the mitochondria makes these reactions the more the inner membrane folds.
Prion proteins are small infectious particles that are formed by the miss-folding of the protein structure. It is believed the miss-folding of such proteins has been the cause of disease such as Bovine spongiform encephalopathy in cows and Creutzfeldt-Jakob disease in humans. The prion proteins that are known to mankind so far suggest that they affect the brain of the affected individual. “A study1 in the British Medical Journal reveals that 1 in 2,000 people in the United Kingdom might harbour the infectious prion protein that causes variant Creutzfeldt–Jakob disease (vCJD).”(Callaway, 2013). The study therefore shows that a high number of people are at risk and this is a cause for concern as the prion protein which is miss-folded prompts normal proteins present in the brain, to alter their structure so they also become miss folded. The miss folded structure is understood to be very stable and as levels of the protein build up within the infected tissue this results in destruction and eventually death of the cell. The prion protein, PrP is thought to be the cause of all mammalian prion diseases but the structure of the protein is yet to be discovered. The normal cellular form of the prion protein is PrPc, whereas the miss folded scrapie form is PrPSc. PrPc is constructed from 209 amino acids and one disulphide bond and are found on cell membranes. “Several topological forms exist; one cell surface form anchored via glycolipid and two transmembrane forms.”(Hedge et al, 1998). The miss folded form, PrPSc has more Beta sheets however the normal form PrPc has Alpha structure present. “Fourier-transform infrared (FTIR) spectroscopy demonstrated that PrPC has a high alpha-helix content (42%) and no beta-sheet (3%), findings that were c...
The Structure and Function of Carbohydrates Large biological molecules are called macromolecules, there are giant molecules (polymers) made up of repeating units (monomers). Carbohydrates are one of the main classes of biological molecules. Macromolecule units (monomers) are joined together by condensation reactions and hydrolysis reactions split macromolecules down into their individual units. Carbohydrates are molecules that contain elements of carbon, hydrogen, and oxygen. Carbohydrates have a 2:1 hydrogen to oxygen ratio, there are twice as many hydrogen atoms as oxygen atoms (the same proportion as in water).
By definition, a cell is life's basic unit. In practice, the cells share several mechanisms across different animals, plants, and microorganisms. Two fundamental differences exist between the architecture of cells for different classes of organisms (Jan, 2014). Lipids build and maintain both the plasma (the external bilayer) and the nuclear membrane within a cell. In addition, the thick filament of proteins (actin filaments and microtubes) confer rigidity to the cytoskeleton of the cell. Factors, such as physical forces acting on a cell as and the cell’s mechanical environment control gene regulation (the rate of production of proteins). In animals, the polymer filament gel (network) regulate the motility of cells. In fact, forces acting on the polymer gel tend to deform the cell membrane.
Membranes play an integral function in trapping and securing metabolic products within the borders of a cell within an aqueous environment. Without a selectively permeable border surrounding sites of anabolic function, potential useful products of this metabolism would simply diffuse away in the aqueous environment contained within and surrounding the cell. However, securing metabolites within the cell also comes with a price of not being able to acquire potentially useful compounds from the surrounding environment. Some very small gases and polar uncharged compounds are able to simply diffuse across this membrane, moving to the site of lower concentration on either side of the membrane. However, larger uncharged and charged polar molecules,
Protein have connection with amino acid to help in functions of: skin, muscle, hair and bones
An enzyme is a biological catalyst (Purchon 2012). Its most basic function is to speed up the rate of reaction (Enzymes (n.d.). Without the existence of enzymes in living organisms, the process of digestion would take weeks. The function of our muscles, nerves and bones will also decrease in efficiency (Purchon 2012). Therefore, the activities in living systems are dependent on and mostly controlled by enzymes. Similar to other catalysts, enzymes can be reused multiple times, however, their natural properties are easily taken away or altered by heat (Purchon 2012). In order for enzymes to maintain their qualities, they need to be in body temperature and a specific pH (Purchon 2012). The reason why enzymes are so sensitive to heat and pH is because they are protein molecules (Purchon
Eighteen percent of our body weight is made up of carbon. Carbon atoms make up important molecules in our bodies such as proteins, DNA, RNA, sugars, and fats. These molecules are called macromolecules. Carbon bonding to itself results in a wide variety of organic compounds, which means that organic compounds are carbon-based carbons. Most matter in living organisms that is not water is made of organic compounds. Nearly everything that is touched is organic. Four main classes of organic compounds that are needed for life are carbohydrates, lipids, proteins, and nucleic acids.
Proteins are considered to be the most versatile macromolecules in a living system. This is because they serve crucial functions in all biological processes. Proteins are linear polymers, and they are made up of monomer units that are called amino acids. The sequence of the amino acids linked together is referred to as the primary structure. A protein will spontaneously fold up into a 3D shape caused by the hydrogen bonding of amino acids near each other. This 3D structure is determined by the sequence of the amino acids. The 3D structure is referred to as the secondary structure. There is also a tertiary structure, which is formed by the long-range interactions of the amino acids. Protein function is directly dependent on this 3D structure.
"Within a single subunit [polypeptide chain], contiguous portions of the polypeptide chain frequently fold into compact, local semi-independent units called domains." - Richardson, 1981
Proteins (macronutrient), which are found in animal products, nuts and beans, they help to build new cells, maintain tissue and synthesis new proteins essential for performing basic bodily functions. Proteins are in abundance in the human body and are present in the outer and inner membranes of all living cells (Dummies, 2018). Proteins are essential for building new cells, maintaining tissue and helping new proteins needed for basic bodily function (