How the structure of proteins is related to their function Essay The primary structure of a protein is made from long chains of amino acids joined by polypeptide bonds. Its secondary structure is when the amino acid sequence starts to coil or fold into either a beta pleated sheet or an alpha helix. The tertiary structure determines the shape of a proteins active site. The tertiary structure is made up of hydrogen, ionic and disulphide bonds between the amino acid sequences. If the amino acid sequence is altered in any way it will have repucutions on the secondary and tertiary structure because bonds will be formed in different locations and therefore a different 3D structure will be present, thus meaning shape of the active site will change in enzymes.
There are many molecules within cells and organisms that must have complimentary shapes that fit together in order for them to carry out their function. One type of molecule for which this is extremely important is enzymes. There are two models that demonstrate how this may work, the first of which is the lock and key model in which the substrate and enzyme binding site have complimentary shapes so that the substrate or subtrates fit perfectly into the enzyme, which joins or separates them. The second model, the induced fit model, is similar, however the enzyme moulds its shape to match the substrate. There are many processes in which it is important that these shapes fit, for example DNA helicase, RNA polymerase and DNA polymerase must all have the correct shape in order for DNA strands to separate, mRNA to form and DNA to then rejoin during polypeptide synthesis.
Chaperones • Some proteins have trouble finding or forming their correct conformation. A protein chaperone can accompany the original protein and supervise and help it to assemble correctly. • PrPSc is acting like a chaperone in BSE but not positively. • PrPC is the protein that is getting influenced negatively. • This influence will turn all of the PrPC into PrPSc and aggregate inside the cell and kill the cell (Reynaud,
Cystic fibrosis is an inherited disease that affects the lungs and digestive system. In patients with cystic fibrosis, they inherit a defective gene on chromosome 7 called CFTR (cystic fibrosis transmembrane conductance regulator). CFTR is a transporter protein that transports chloride ions across the cellular membranes of cells in the digestive tract, pancreas, reproductive tract, liver, skin, and lungs. Cystic fibrosis patients have a deletion of three base pairs in the protein CFTR’s nucleotide sequence. This deletion causes the amino acid phenylalanine to be removed.
Within the body, biological catalysts are vital to many processes and without them bodily reactions would be too slow to sustain life. The functions of these substances are both anabolic and catabolic. Some examples of catabolic enzymes are pepsin, a substance released in the stomach to degrade proteins and the many catalysts involved in cellular respiration, a bio-chemical pathway similar to photosynthesis. An example of an anabolic, enzyme-facilitated process would be the production of proteins, which involves catalysts shaping and assembling structures of amino acids. Catalysts are important not only to living
In this case, the most effective factor is the reactant concentration, where the reactant is the enzyme. Enzymes are composed of proteins; therefore their characteristics reflect the properties of proteins which are extremely interesting properties that make enzymes little chemical-reaction machines. The purpose of an enzyme in a cell is to allow the cell to carry out chemical reactions very quickly. These reactions allow the cell to build things or take things apart as needed. This is how a cell grows and reproduces.
In this way genes program the basis of our biology. Our body shape and size, as well as our behaviour are caused by the interaction of our biology with broader environmental factors. A human being is the result of the interaction of genes and the environmental influences they are exposed to. The maturation theory- what is it? Some aspects of development, such as the ability to speak a first language, are the thought to be due to an in built genetic process.
Enzymes are "biological catalysts." "Biological" means the substance in question is produced or is derived from some living organism. "Catalyst" denotes a substance that has the ability to increase the rate of a chemical reaction, and is not changed or destroyed by the chemical reaction that it accelerates. Generally speaking, catalysts are specific in nature as to the type of reaction they can catalyze. Enzymes, as a subclass of catalysts, are very specific in nature.
On the surface of the enzyme is an active site that temporarily binds the reactants or substrates forming an enzyme-substrate complex. The catalytic action of the enzyme then converts the substrate to a product or products. This conversion can take the form of a synthesis (building more complex molecules), a decomposition (splitting of the substrate), an oxidation/reduction (addition or removal of electrons), or an isomerization (rearrangement of atoms within a molecule). When the product or products are released, the enzyme emerges unchanged and available to convert more substrate into more products. Since enzymes can be used again and again, they are effective even at low concentrations.