Type: Process Essays
Sample donated: Stuart Hodges
Last updated: February 16, 2019
Task 1: A primary structureis the distinctive sequence of amino acids which make up a protein. Thissequence is also known as a polypeptide chain.
Ala-Gly-Val-Tyr-Arg-Leu-Ser-Met-Asn-Cys-ProAGVYRLSMNCPTo make it less complicated and abbreviate each amino acid residue witheither a three letter or one. The protein chain in the primary structure dependsall on the identification of the amino acid sequence. These molecules determinehow the molecular chain will fold. Diagram: The polypeptide bonds are created by enzyme catalysedcondensationreactions. Then it is broken by the enzyme catalysed hydrolysisreactions.
The monomers in the diagram below show that they form proteins. Proteins are made up of a variation of amino acidpolymers, and they are different type of bio-molecule in our bodies.Differentprotein types include enzymes that catalyse chemical reactions receptors thatcontrol signalling in bodies. Haemoglobin carried oxygen throughout the bloodstream,muscle and organ tissue, which gives your body structure and mobility, and somany other things.Amino acids form peptide bonds with one another, thepeptide bond between the two–NH and CO units, cause a condensation reaction. This is called a carboxyl group. Every amino acid has this.
A condensationreaction is the reaction of two small molecules that make a larger molecule– e.g. H2OIn this process water is removed. *draw picture* Proteinis a long polypeptide chain of amino acids. Amino acids are attached togethervia the peptide bonds. Then they make chains of amino acid chain.
Once the primary structure of thepolypeptide is formed, it begins to twist into regular patterns that make upthe secondary structure. The primary structure just describes the linear sequence ofamino acids, and it is dictated by the peptide bond that links to each aminoacid. This is a simple linear structure. You take an amino acid and bond themtogether and that bond is called a peptide bond, very strong covalent bonds. Secondarystructure forms as hydrogen bonds form between backbone atoms.
The tertiarystructure is the final fold of the protein and that is held by hydrogen, ionicand disulfide bonds. The proteins which have more than one polypeptide chain isa quaternary structure and that is represented by three dimensional arrangement. + Beta pleated sheet and ?loop. These twists are formedof as a regular pattern of hydrogen bonds between NH and C=O groups on theepolypeptide chain.
The beta sheet are formed by hydrogen bonds and there structure iszigzag. In secondary structure there arehydrogen bonds forming between the peptide groups. In the secondary structure the majorbond is the hydrogen bond apart from the peptide bond and disulphate bond. Insecondary structure the structure is referred to the plated sheet that aproteinchain can form because of hydrogen bonding.
When the process is finishedthat whole shape of the polypeptide is refereed as tertiary structure- So afterthe polypeptide chains form they are now called proteins. This happens inthe r groups of amino acids in the chain. 6 Each amino acid has a central atom with anamino acid group and a carboxyl group and a hydrogen atom.
When a watermolecule is occurred during a reaction between NH2 of on amino acid and –COOHof another amino acid this is when thepeptide bond is formed. Disulphide bond occurs only incertain amino and specific group which is referred as a sulfhydryl group. When the SH groups of two cysteine residuesare covalently linked as a dithiol by oxidation that is when disulphide bondsarise. Hydrogen bond is a bond between ahydrogen atom and an electronegative atom like oxygen, nitrogen. In amino acidsthe electromagnetic attract interactions between polar molecules. So the bondis weak when hydrogen is stuck to a highlyelectronegative atom, like N or O. Task 2 Tertiary structurethere are hydrophobic bonds, hydrogen bonds, ionic bonds, Van der Walls forces,Di-sulphite bonds. As amino acids interact the protein may fold upon itself.
In the Quaternarystructure there are hydrophobic bonds, hydrogen bonds, ionic bonds, Van derwalls forced an di-sulphite bonds. Ionic bond is a bondbetween oppositely charged amino acids of an aspartic acid which is a baseacidic amino acid it is a negatively charged where as lysine is a positivelycharged amino acid. Van der walls force is a weak electrical force betweenatoms. Also it is the sum total of all non covalentbonds between electricallyequal molecules. They hold molecules together. Hydrophobic: These blue molecules in thefigure are hydrophilic regions and the red ones are the hydrophobic regions.The hydrophobic is also referred as water-hating amino acids. Hydrophobic interactions actuallythe bond between two no polar groups.
The structure of the side chain can closely associate and areprotected from interaction with solvent water. So each type of a protein has a three-dimensionalstructure; this shows the order of the amino acids in its chain. A protein can be unfolded or denatured by exploringwith certain solvents, which causes disturbance to the no covalent interactionsthat hold the folded chain together. This causes the protein to transfer into aflexible polypeptide chain which loses its original shape. When the denaturingsolvent is removed, the protein often refolds automatically.