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School of Forensic and Investigative Sciences Assessment Coversheet Module Code Module Title Student’s name Student ID Number Course/ Subject Assignment Title/ Number FZC008 Module Tutor Karen Lupton Biochemistry Rosie Bowers G 2 0 6 2 5 2 9 Foundation applied science Enzymes Essay 7 ‘I confirm that this piece of work which I have submitted is all my own work and that all references and quotations from both primary and secondary sources have been fully identified and properly acknowledged in footnotes and bibliography.’ Signature: Rosie E Bowers Extension Agreed date: Date: 26.3.15 Submission Deadline 27.3.15 Extension Agreed by: Work submitted should be presented in the following format: Grade* Double line-spaced, on A4 paper In Arial or Times New Roman font in black ink Learning Outcomes To be completed by the student Describe and apply key biochemical principles necessary for study on university level programmes. Describe and explain the structure and function of carbohydrates, lipids and proteins General comments: Strengths: Areas for improvement: Module Tutor Feedback Rosie Bowers ID: 20625297 If there is something you do not understand or some aspect on which you want further information, and you have not yet had the opportunity, you must make an appointment with your tutor to discuss this assessment and the feedback given. You may be asked to use this feedback to reflect upon your personal development (PDP). Upon receipt of the feedback from your module tutor, please complete below your reflections on this assessment for your future action. 1st Marker Signature Moderation signature** Date Date 1|Page Word Count: 1031 Rosie Bowers ID: 20625297 Self-Assessment of Your Assignment Please respond to the following questions at the point just before handing in your assignment. It will help me to provide you with more useful feedback about your work, and will also provide me with useful feedback about how you are finding the programme to date. Questions 1 Your replies to the questions What do you think was the Getting to fully thing you did best in this explore enzymes assignment? and how they work. 2 What was the hardest thing about this assignment? Trying to find relevant information from reliable sources to reference. 3 If you had the chance to start this assignment again from scratch, how (if at all) might you decide to go about it differently? Discuss the structure a little more. 4 Jot down 3 short questions you could like me to answer about this example of your work. 1. Was the information included completely relevant? 2. Is there anything else I could have added? 3. Was the essay structured properly? 2|Page Word Count: 1031 Tutor’s Response Your Action Points Rosie Bowers ID: 20625297 Describe the chemical structure and discuss the factors that modify enzyme structure and/or function. Enzymes are essential intracellular biological catalysts. They help in the catalysing of the metabolic reactions within the body. They reduce the activation energy required for the reaction to take place. (1) Enzymes have the potential to effect a person’s phenotype and therefore there physical appearance. This is because they aid in the reactions involved with growth and development. Enzymes have their own nomenclature. They can be categorised by the reactions they catalyse. These are: Oxidase (Oxidisation/reduction reactions), Hydrolase (Hydrolysis reactions), Isomerase (Isomerisation) and Ligase/Synthase (catalyse the joining of two substances). (2) Enzymes are globular proteins. (3)The structure of enzymes is very specific. They are made up of primary structures that are a simple sequence of amino acids that code for the enzyme protein chain. They are joined by peptide bond during a condensation reactions. These primary structures fold, bend and twist and are held by hydrogen bonds to produce structures such as α helix but also as a zig-zag structure called a ß pleated sheet. The tertiary structure is the precise 3D structure of the enzyme protein with various secondary structures. These are held together by ionic attraction between the R groups, disulphide bridges formed between cysteine, hydrogen bonds and hydrophobic attractions. The shape of active site of the enzyme complimentary to the substrate is determined by the specific structure of the primary, secondary and tertiary structure. This very specific structure is altered by temperature and PH amongst other things. (4) Chemically almost all enzyme reactions are reversible. The mechanism can be shown as (5). A and B are the reactants and C and D are the products. (4) The reactant will combine with the products until it reaches equilibrium. The time taken for the reactant to be converted into the product using the enzyme is dependent on a number of limiting factors. These limiting factors can also modify the enzymes and change the function 3|Page Word Count: 1031 Rosie Bowers ID: 20625297 (4) Temperature is a limiting factor. The temperature of the reaction can cause it the reaction to speed up. The reactant will move around faster and therefore collide more frequently. As a result the product is formed quicker. The enzyme will have an optimum temperature in which the enzyme will work at its best. Just as the rate of reaction will decrease as the temperature decreases. (6) For example in metabolic reactions. When a body become hyper/hypothermic it is no longer at its optimum temperature for enzyme reactions and so the body in the case of hyperthermia the body’s temperature is increased and the enzymes can begin denature where as if the body become hypothermic the metabolic reactions will slow down to a dangerously low rate. (4) After that temperature the enzyme will denature. If the temperature of the enzyme is too high it can modify the shape of the active site rendering the enzyme ineffective. Where most enzyme reactions are reversible, the denaturing of the enzyme is irreversible. This can also be the case for the PH. The PH also has an optimum PH in which the enzymes work the best. For example digestive enzymes in the stomach work best at around 2 on the PH scale. An extreme PH increase or decrease will cause the enzymes active site alteration. (4) The H+ and OH- ions in acid and alkali solutions alter the ionic and hydrogen bonding holding the whole structure together. The active site will no longer be complimentary to its substrate and as a result the enzyme will be denatured. There are also other non-chemical and thermal components that can modify the enzymes structure and therefore their active site. Inhibitors can be competitive and non-competitive which can be further broken down into reversible and irreversible inhibition. (6) Inhibitors are a molecule than effects a single amino acid or even a side chain which ultimately alters the final structure of the enzyme. (4) Competitive inhibition happens when a compound with a similar to shape to that of the substrate bind to the active site instead of the complimentary substrate. This makes that substrate unable to bid and the reactants cannot convert into the product. Competitive inhibition is classed a reversible. The inhibitor will remove from the active site of the enzyme and the enzyme can be used again. By increasing the substrate concentration in the experiment, the enzyme is more 4|Page Word Count: 1031 Rosie Bowers ID: 20625297 likely to collide with the substrate to produce the enzyme-substrate complex rather that producing an enzyme-inhibitor complex. Non-competitive inhibition, on the other hand, modifies the structure and active site of the enzyme rather that blocking the active site and has no similarity to the substrate at all. (4) Non- competitive inhibitors bind covalently away from the active site. Ultimately they interfere with the tertiary structure of the enzyme which leads to the alteration of the active site. Enzymes with attached non- competitive inhibitor are classed as ‘switched off’. This is a reversible reaction, when the inhibitors are removed the enzyme will become functional again. Irreversible inhibition is a category on its own. Unlike reversible inhibitors they destroy the overall tertiary structure of the enzyme rendering them completely ineffective. (6) Some irreversible have no similar structure related relationships to a substrate. They bind covalently like non-competitive inhibitors but in some cases they can also bind by other means to an active site. As a result they break down essential functional groups needed for the active site to be functional. Examples of irreversible enzymes include cyanide. Cyanine will bind to respiratory enzymes and therefore respiratory reactions cannot take place. In the case of the human body irreversible inhibitors can be fatal. All in all, enzymes are an essential factor in the function of the living organism. They have specific structure that allows them to catalyse individual biochemical reactions that have substrates complimentary to that of its active site. Other molecules can alter and modify that active site making it impossible for a substrate to bind. Due to the specific and quite fragile tertiary structure even the slightest change in PH or Temperature can alter the effectiveness of the enzymes. 5|Page Word Count: 1031 Rosie Bowers ID: 20625297 Bibliography. (1) Mike Boyle, Katherine Senior. Collins Advanced Science: Biology, 3rd ed. London: Collins; 2008. Pg73-93 (2) University Of Arazonia. Energy, Enzymes and catalyst problems. http://www.biology.arizona.edu/biochemistry/problem_sets/energy_enzymes_ca talysis/01q.html(accessed23.3.15) (3) Dr. Edward Meyertholen Enzymes. http://www.austincc.edu/emeyerth/enzymes (accessed 23.3.15). (4) Jim Clark. Enzyme Inhibitors. http://www.chemguide.co.uk/organicprops/aminoacids/enzymes3.html (accessed 23.3.15) (5) Image can be found at: https://encryptedtbn0.gstatic.com/images?q=tbn:ANd9GcS6HfSAIXCOsQEG8GYwU9ClNx9axTOxHXb--41FgKplfRM23kWlg (6) Rakesh Sharma (2012). Enzyme Inhibition: Mechanisms and Scope, Enzyme Inhibition and Bioapplications, Prof. Rakesh Sharma (Ed.), InTech, Available from: http://www.intechopen.com/books/enzyme-inhibition-andbioapplications/enzyme-inhibition-mechanisms-andscope 6|Page Word Count: 1031