...Chapter 3 Enzymes Learning Outcomes Candidates should be able to: (a) explain that enzymes are globular proteins that catalyse metabolic reactions; (b) explain the mode of action of enzymes in terms of an active site, enzyme/substrate complex, lowering of activation energy and enzyme specificity; (c) [PA] follow the progress of an enzyme-catalysed reaction by measuring rates of formation of products (for example, using catalase) or rates of disappearance of substrate (for example, using amylase); (d) [PA] investigate and explain the effects of temperature, pH, enzyme concentration and substrate concentration on the rate of enzymecatalysed reactions; (e) explain the effects of competitive and non-competitive inhibitors on the rate of enzyme activity; (f) use the knowledge gained in this section in new situations or to solve related problems. Enzymes are globular protein which act as catalysts • Enzymes are protein molecules defined as biological catalysts which speed up a chemical reaction and remain unchanged at the end of reaction. • Enzyme names end in –ase E.g. amylase, ATPase • Enzyme are globular proteins. Enzymes are globular protein which act as catalysts • Enzyme molecules are coiled into a precise threedimensional shape, which hydrophilic R groups (side-chains) on the outside of the molecule ensuring that they are soluble. Enzymes are globular protein which act as catalysts • Enzyme molecules have active site. • The active site of an enzyme is a region...
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...Title: Enzyme Introduction The main reason for conducting this experiment is to establish the various factors that affect enzymes and reaction rates. Various experiments have been conducted to help gain a wide range of the factors that affect enzyme controlled reactions. Enzymes are affected by very many factors. It was the main aim of this experiment to establish these factors and the manner in which they affect them. This experiment also seeks to establish the manner in which some enzymes like Catalase affect the rates of reactions (Cohnheim 2009). Methods To establish the factors that affect enzymes, the procedures for the experiments to be carried out had to be almost perfect. For this reason the apparatus to be used had to be cleaned thoroughly just before commencing the experiment. To avoid differentiated results, similar kinds of apparatus were used all through the experiment. In this case glass test tubes were used. Also measuring apparatuses used were of the same size and volume. In this case four experiments were carried out. The first experiment is to establish the manner in which the enzyme Catalase affects reaction rates. The procedure of this experiment is as follows; using a pencil, label tree test tubes as test tube 1, 2 & 3. On these test tubes, label two marks using the pencil. These are at the 1cm mark and at the 5 cm mark. For the first test tube, pour in Catalase enzyme up to the first mark and add Hydrogen Peroxide up to the...
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...Effects on Enzymatic Activity Tyler Mitchell BSC 118-002 Shon Johnson November 1, 2011 Abstract Without the effects of enzymes, many crucial chemical reactions would not be able to take place at the rate of which they were meant to perform. We conducted this series of labs in order to discover the effects of different biological and environmental aspects on enzymatic activity. In our first experiment, we looked at the effects that enzyme concentration had on amylase activity. We hypothesized that the higher the concentration of the enzyme, the higher the rate of reaction would take place. We found that a higher concentration of amylase led to a faster rate of reaction, proving our hypothesis to be correct. In our second experiment, we tested the effect the concentration of substrate would have on enzymatic activity. We hypothesized that the lower concentration of the substrate would not change the speed of the reaction. The experiment proved this hypothesis to be wrong because the speed of the reaction slowed down as the concentration lowered. In the third experiment, we tested the effects that different pH levels would have on enzymatic activity. We hypothesized that the more acidic the solution was, the lower the rate of the reaction will be. In Areekijseree’s article, it states that optimal pH levels for amylase are between 4 and 5, and 6 and 8 (Areekisjseree, Engkagul, Kovitvadhi, Thongpan, Mingmuang, Pakkong, Rungruangsak-Torrissen, 2004). This contradicts...
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... Photosynthesis also occurs in algae, plants, and certain bacteria. In contrast, respiration takes glucose (sugar), along with other organic compounds oxidizing them to develop carbon dioxide. Respiration is the metabolic reaction in organic cells, biochemical energy into adenosine triphosphate/ATP. Each cycle depends on the other, in order for the ‘complete cycle’ to transpire. When it comes to receiving energy from the foods we eat, photosynthesis stores the energy and respiration releases it. Both cycles are important to ensure continuous life on earth. Photosynthesis and respiration are connected between plants and animals based on the reactants and products of both pathways by the usage of autotrophs and heterotrophs. An autotroph are organisms the have the ability to manufacture their own food (“Autotroph vs. Heterotroph” n.d.). Heterotroph organisms are essential in respiration and are not an element in photosynthesis. When it comes to the autotroph, this is done by the using the available substances, in their environment, with light (photosynthesis) or chemical energy (chemosynthesis). Energy is transferred from sunlight to ATP/adenosine phosphate by energy being extracted from the ATP molecule. While in the cell, a reaction removes one of the phosphate Running Head:...
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...Enzymes and pH pH is a measure of H+ concentration. The higher the concentration of H+ the lower the pH values (acids) A hydrogen ion has a (+) charge so will be attracted to negatively charged molecules or parts of molecules. As like charges repel, positive molecules or parts of molecules will repel hydrogen ions. Large numbers of hydrogen bonds and ionic bonds are responsible for holding the tertiary structure of an enzyme protein in place. This ensures that the active site is also held in the right place. These bonds are due to the attraction between oppositely charged groups on the amino acids that make up the enzyme protein. Because of their charge, hydrogen ions can interfere with the hydrogen and ionic bonds in the molecule holding the tertiary structure in place. This means increasing or decreasing the concentration of hydrogen ions can alter the shape of the tertiary structure and therefore the shape of the active site. This can also aler the rate of an enzyme-controlled reaction. The induced-fit hypothesis suggests that an important part of catalysis in the active site relies on charged groups on the R-groups of the amino acids that make up the active site. Increasing the concentration of hydrogen bonds will alter the charges around the active site, as more hydrogen ions are attracted towards any negatively charged groups in the active site. Optimum pH At the optimum pH, the concentration of hydrogen ions in the solution gives the tertiary structure...
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...11, 2013 1. Explain how photosynthesis and respiration are linked in order to provide you with energy from the food you eat. Photosynthesis can be defined as the process that living organisms such as plants use to translate the sun’s energy into chemical energy. Once the plant has translated the sun’s energy into chemical energy it then releases that energy and makes it readily available to other living things (Vermaas, 2007). Aerobic respiration can be defined as nutrients being converted into useful energy. Respiration allows cells to use the energy stored during the photosynthesis process. It’s the chemical reaction that breaks down the glucose and changes it into a larger amount of Adenosine Triphosphate which is also called ATP (Board, 2012). Plants use sunlight to make ATP for its energy source by creating a series of chemical reactions by producing oxygen as a waste product. Next, animals and human beings eat these plants. The nutrients digested by animals and human beings reverse the process by using the ATP as a source of energy. Our cells use the nutrients from the plants and convert the nutrients in a process that uses oxygen (Board, 2012). Once our bodies have used all the nutrients will be need from those plants our bodies as well as animals release carbon dioxide as waste. Photosynthesis and respiration are both means of converting one state of energy into another more useful state of energy at a cellular level (Vermaas, 2007). Although photosynthesis...
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...Enzyme Controlled Reactions Lab |Amount of Substrate |pH 3 |pH 5 |pH 7 |pH 9 |pH 11 | |0.5 g |19 |39 |72 |45 |24 | |1.0 g |39 |81 |145 |91 |49 | |2.0 g |82 |168 |300 |189 |103 | |4.0 g |96 |198 |350 |223 |121 | |8.0 g |96 |198 |350 |223 |121 | Question #1: Describe the relationship between substrate concentration and the initial reaction rate of an enzyme-catalyzed reaction. Is this a linear relationship? What happens to the initial reaction rate as substrate concentration increases? The enzyme and the substrate come together long enough to form a new substance. Yes this is a linear relationship because the substrate and the enzyme work together. The enzyme will actually change shape to fit the substrate so that a reaction can occur. The initial reaction rate of the substrate is variant on the pH level. The...
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...Lactase Enzyme Lab Kailen Roop Biology A1 5/5/15 Roop 1 Table of Contents Introduction……………………………………………………………………………………26 Methods…………………………………………………………………………………....…..7 Results………………………………………………………………………………………....8 Conclusion……………………………………………………………………………………..9 Citations…………………………………………………………………………………….1011 Roop 2 Introduction This paper is about lactose intolerance, how it works and why it happens. This paper will discuss lactose intolerance form a molecular level to the evolutionary level. Also, this paper will outline an experiment designed to show the various levels of lactose and glucose in various samples of milk. First we must understand, what is lactose intolerance? To do that we must first understand what happens in the human body that defines lactose intolerance. The first step is learning what takes place in order to have a chemical reaction. Then, what happens during that reaction to make someone lactose intolerant or non lactose intolerant. Finally, what happened during evolution that makes some people lactose intolerant and some not. Enzymes are proteins that make reactions happen faster. (National Enzyme Company 2015). Enzymes regulate chemical reactions. They do this by binding to molecules called substrates. Enzyme activators are molecules that start or speed up an enzyme’s activity...
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...LAB #3: An Enzyme in Plant and Animal Tissues BACKGROUND INFORMATION Liver and other living tissues contain the enzyme catalase. This enzyme breaks down hydrogen peroxide (H2O2), which is a harmful by-product of cellular respiration if it builds up in cells. In this lab, you will perform reactions with the enzyme catalase. OBJECTIVES: 1. Investigate the enzyme catalase in various tissues. 2. Measure the effect of changes in temperature on reaction rates of an enzyme-catalyzed reaction in a controlled experiment. INTRODUCTION: What would happen to your cells if they made a poisonous chemical? You might think that they would die. In fact, your cells are always making poisonous chemicals. They do not die because your cells use enzymes to break down these poisonous chemicals into harmless substances. Enzymes are proteins that speed up the rate of reactions that would otherwise happen more slowly. The enzyme is not altered by the reaction. You have hundreds of different enzymes in each of your cells. Each of these enzymes is responsible for one particular reaction that occurs in the cell. In this lab, you will study an enzyme that is found in the cells of many living tissues. The name of the enzyme is catalase (KAT-uh-LAYSS); it speed up a reaction that breaks down hydrogen peroxide, a toxic chemical, into 2 harmless substances--water and oxygen. The reaction is as follows: 2H2O2 à 2H2O + O2 This reaction is important to cells because hydrogen peroxide...
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...an enzyme Abstract The experiment was to analyse what reaction temperature would have on Amylase enzyme. We heated alpha amylase solution to set temperatures then tested for the presents starch with iodine solution. Any starch would turn the iodine black. Once the starch had broken down the iodine would remain brown to suggest the presents of maltose. Usually I would expect to find that the reactions would increase as the temperature increased. After it reached its optimum temperature then the reaction would slow down rapidly or stop all together. However throughout the experiment we uncovered a number of flaws, the flaws would have contributed to the failure of this experiment and the rejection of my hypothesis. Introduction Enzymes are proteins that were made during protein synthesis. They are globular in shape and of a tertiary structure that has an active site. The protein molecules act as a catalyse biochemical reaction in living organisms. (Indge, B (1993), A-Z Biology. London. Wearset. 90). A catalyse is something that makes a chemical reaction happen more quickly without itself being changed. This means that enzymes can be re-used. Enzymes work by lowering the activation energy necessary to start a reaction. As less energy is necessary, biochemical reactions can take place at the temperatures and pressures found in living cells. (Indge, B (1993), A-Z Biology. London. Wearset. 90). The diagram on the left illustrates the action of an enzyme. As...
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...Biology HL 20/9/2013 How Substrate Concentration affects a Catalase Enzyme Reaction RQ How does changing the substrate concentration affect the rate of a catalase reaction in an enzyme? Hydrogen peroxide was used as the substrate and the rate was measured by oxygen production. Hypothesis If the substrate concentration is increased then the rate of a catalase reaction will also increase until it reaches the optimal concentration or saturation point and will remain constant. This is because there will be more substrate molecules in a higher concentration therefore a higher frequency of collisions. This increases enzyme activity and more product will be formed. However at a certain concentration the enzymes will become saturated (all active sites are full), so an increase in substrate molecules will stop affecting the rate. Variables Independent Variable - Hydrogen peroxide concentration Dependent Variable – rate of catalase reaction by measuring the volume of oxygen produced after five minutes Controlled Variables – performed at room temperature (21 Celsius), catalase used (potato), weight of potato (1g) in each trial, time given for reaction to take place (5 minutes), method & apparatus Apparatus 1. Safety goggles & apron 2. Measuring cylinder, 100 cm3 (+/- 0.5cm3) 3. Large plastic tub 4. Access to sink/water 5. Clamp stand, boss and clamp 6. Rubber bung and delivery tube 7. 9 large test tubes 8. Stopwatch (+/- 0.01s) 9. Hydrogen Peroxide, range of concentration:...
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...Lab Background: Enzymes are proteins that catalyze or control metabolic reaction. Enzymes work by lowering the amount of activation energy needed so the reaction will happen more quickly. The molecules that an enzyme acts upon are called substrates, the substrate solutions used in this lab were milk and water. In this lab, the enzymes are specific for particular substrates. The enzyme (junket tablet) converts these substrates into different molecules by curdling. If the enzyme concentration required to start the reaction increases and speeds up a reaction, then it will remain unchanged unless certain limiting factors are introduced. Analysis & Discussions: Enzyme concentration: According to figure 5, if the amount of concentration of junket tablet increased, the time for initial curdles to form in room temperature milk decreased. This was evident because the curdles that were formed on the edges of the test tube was much faster as the amount of enzyme concentration increased by 1/5th each. The trend shows the inclination of time versus the concentration of the junket tablet, indicating the presence of a higher amount of enzymes controls the decrease in time. Moreover, the curdles were then formed larger by the last few trials according to table 5. The hypothesis is proven true by figure 5, where the rate of reaction increased as the enzyme concentration increased except at trial four where it decreased slightly. In conclusion, the higher the enzyme concentration, the...
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...Temperature on the Enzymatic Activity of Amylase Enzymes are biological molecules or proteins that act as catalysts and help complex reactions occur everywhere in life. The enzyme and the substrate are in the same area, closely together. The enzyme grabs on to the substrate at a special area called the active site. The combination is called the enzyme/ substrate complex. After this, the substrate is changed. It can either be broken down or combined with another molecule to make something new. When this is complete, you will have the enzyme, still unchanged, and the product. The enzyme then releases the product. When the enzyme lets go, it returns to its original shape. It is then ready to work on another molecular substrate. In...
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...structurally, such as cellulose Lipids H O H H C H H C H H C O C O O C O O These come in many varieties: fats, oils, cholesterol, steroids, and more, and have uses in cellular membranes, insulating and protecting, and also act as a minor energy supply C H Proteins Proteins have several uses, such as for transport and structure; but they are also the basic components of all enzymes, hormones, antibodies, haemoglobin, ribosomes, and many more materials Water H O H Another essential life component, this is the most important content of many reactions forming most of these molecules, and also metabolic reactions; water is also an essential structural component in plants, and in the diet of animals Nucleic acids These are responsible for the formation of both DNA and all forms of RNA molecules, consisting of individual nucleotides www.asbiology101.wordpress.com Enzymes These are proteins which are used in many reactions – their function is to catalyse metabolic reactions in the vast majority of living organisms There is a lot of chemistry knowledge in the Biological Molecules section of this module, which is why it is important that you are aware of a few chemistry basics, such as the types of chemical bond. This unit on Biological Molecules is centred...
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...OF ENZYMES Enzymes are extremely important and without them, the reactions in living organisms would be so slow they would hardly proceed at all. They enable metabolic reactions to proceed rapidly at low temperatures, and as well as speeding up reactions they also control them. There are two main groups of enzymes: intracellular and extracellular. INTRACELLULAR: Occur inside cells where they speed up and control metabolism. EXTRACELLULAR: Produced by cells but achieve their effects outside the cell – includes digestive enzymes that break down food in the gut. Each enzyme is usually specific to particular reactions, and are pH sensitive, with every enzyme having its own range of pH in which it functions best. They are not destroyed by the reactions which they catalyse, meaning they can repeat a reaction over and over. (McMonagle,2015) In an enzyme controlled reaction, the substrate molecules bind with the enzyme to form an enzyme-substrate complex. The reaction then takes place and the product leaves the enzyme. As mentioned above, the enzyme (unchanged by reaction) can then be used again. Below is the equation, with the double arrow meaning that the reaction can go either way, depending on the amount of substrates and products – this ensures a equilibrium, meaning the enzyme will switch if there is an abundance of product and not enough substrates, and vice versa. (Advanced Biology, pg124, 2000) ENZYME + SUBSTRATE ENZYME-SUBSTRATE...
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