...Introduction (5 marks) Enzymes are globular shaped proteins that are found throughout the body, with their main function being to act as biological catalysts. An enzyme can act to speed up or regulate the rate of the reaction, in order to maintain an efficient rate of biological reactions. Enzymes, whilst having an important role in the reaction of many chemicals within the body, are not consumed in the reaction, and so are able to catalyze many reactions in their life cycle. Enzymes are able to reduce the activation energy of the reaction; the energy required to break bonds between the reactants, and form new bonds in the products, which allows more product to be formed. (Marieb and Hoehn, 2010, pp.51-53). Enzyme activity is affected by changes in the pH of their solution. For each individual enzyme, there is a corresponding pH at which, that particular enzyme’s activity will be at it’s maximum. This is known as the optimum pH. If the pH of the solution is getting closer to it’s optimum pH for that particular enzyme, then the activity of the enzyme, and therefore it’s rate of reaction, will increase. At extremes of pH (either extremely acidic or basic) enzymes tend to become denatured; a state in which they lose all of their biological activity. (Worthington Biochemical Corporation, 2011). Temperature has the ability to increase the reaction rate of chemical reactions, by increasing the kinetic energy of the molecules themselves. By increasing the kinetic energy...
Words: 2043 - Pages: 9
...The Effects of Peroxidase on Enzyme Activity Gianna Crowe Bio Lab 117 October 16th, 2014 Most enzymes are proteins that speed up reactions and are characterized as catalysts. Enzymes work in such a way that when the right chemicals of a molecule are present for the enzyme, it will fully fit the shape. The part of the particular shape is called the active site of the enzyme, since this is where the reaction occurs. The molecule that the enzyme works on is called the substrate. An enzyme reaction includes a substrate (substance) that is converted to another product. The unique shape of the active site of the enzyme allows it to bind with only certain kinds of molecules, which is the substrate of the enzyme (Strobl 2014). A substrate binds to the active site of the enzyme to form a enzyme-substrate complex for a very short time, this then becomes part of a new formation and a new product of a specific reaction is formed then released freeing the active site, allowing the enzyme to repeatedly bind another substrate. Enzymes are produced by all living things, and are a necessity to life. They are responsible for constructing, synthesizing, carrying, dispensing, delivering, and eliminating the many chemicals associated in living organisms (Colpa 2014). An example for how enzymes work in living organisms would be the process of food digestion, enzymes work to break down food and speed up the digestion process. Factors that affect enzyme activity deal with environmental conditions...
Words: 2496 - Pages: 10
...Introduction Enzymes are biological catalysts. Catalysts are substances that increase the rate of chemical reactions without being used up themselves. Enzymes are also proteins. They all have different and complex shapes that allow smaller molecules to fit into them. The place where these substrate molecules fit is called the active site. The shape of an enzyme can change; its active site may no longer work. It is said the enzyme is denatured. They can be denatured by high temperatures or extremes of pH. Like all other proteins, enzymes are made of amino acids. Each enzyme is made of between 100 to 1 million amino acids placed like pearls on a string. Each amino acid is bonded to the next by chemical bonds. Some enzymes can be made from 20 different kinds of amino acids. No two enzymes are alike. Each enzyme has its own unique sequence of amino acids, which is determined by the genes in the cells. Enzymes consist of millions of amino acids placed one after the other, however, do not look like a long string of amino acids. In most enzymes the string is coiled and folded thousands of times to form a highly complex three-dimensional structure. It is the chemical interactions between the amino acids that force the enzymes into their three-dimensional structure, which is held together by the many different links between the different amino acids. Each enzyme has its own unique three-dimensional structure that determines the function of the enzyme. The three-dimensional structure...
Words: 960 - Pages: 4
...Title: What is the effect of temperature on Enzyme activity? Purpose: Enzymes are proteins that speed up chemical reactions in cells. They break down molecules called substrates. Each enzymes have only one substrate that breaks down. Enzymes are produced in the cells of the body and affect the rate of almost all the chemical reactions which take place in living organisms. The rate of enzymes activity is influenced by temperature, pH, and substrate concentration. The purpose of this lab was to determine the affects of enzyme activity under specific temperature changes, pH values and substrate concentration. Since heat increases the rate of most chemical reactions, the addition of heat causes faster molecular movement. Most enzymes active in living tissue becomes denatured, their secondary or tertiary protein structure breaks down, at the temperature above 40 degrees C. In the effects of pH, it is expected that the changes in pH would have an effect on the action of enzymes. Lemon juice helps keep the apple from growing, because its full of ascorbic acid (Vitamin C) and it has a low acidic pH level. But extreme high levels of low pH values can result in a complete loss of enzymes activity thus leaving the apple to brown. The effects of substrate concentration, an enzyme substrate complex is formed when a substrate fits into active of an enzyme. The velocity, the rate of speed, at which the enzymes works will increase until it reaches a maximum. If the substrate...
Words: 310 - Pages: 2
...The purpose of this lab was to determine the effect of temperature and pH on the reaction rate of Catecholase. The substrates of catecholase are catechol and oxygen, and it is an enzyme that speeds up chemical processes. Enzymes work best under optimal conditions, and we tested the reaction rate of catecholase with substances containing different temperatures and pH levels. pH measures the acidity or alkalinity of a substance, and is measured on a scale from 1 to 14. Temperature is the measurement of heat found in a substance. We performed two separate tests to determine how varying pH levels and temperature affected the reaction rate of catecholase. For our temperature test, three test tubes were filled with the same amount of water, and ten drops...
Words: 612 - Pages: 3
...and explain how different factors affect the function of enzyme catalysed reactions (inhibitors not required) (10) There are four main factors that affect the rate of reaction on enzyme-catalysed reactions. The first of these is temperature. When increasing the temperature of a reaction the kinetic energy of molecules increases and therefore they more around more quickly and collide with each other more often. This means that within an enzyme-catalysed reaction the substrate molecules collide more often with an enzyme and so the rate of the reaction increases. When the temperature reaches a certain heat that is beyond the enzymes optimum temp the hydrogen bonds within the enzyme vibrate more rapidly and start to break. This in turn alters the shape of the active site so that the substrate no longer fits. The rate of reaction at this point then slows down as there are less enzyme-substrate reactions. Another factor that can affect the function of an enzyme-catalysed reaction is that of pH. Most enzymes have an optimum pH at which the rate of reaction is at its maximum. Small changes in this pH can cause reversible changes in the enzyme structure and can result in inactivation, although large changes may denature the enzyme entirely. A change in the pH means that the active site of the enzyme becomes wrongly charged. This means that at a high or low pH the active site will repel the substrate. It is the amino acid side-chains of the enzymes active site that is affected by free...
Words: 513 - Pages: 3
...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...
Words: 1331 - Pages: 6
...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...
Words: 595 - Pages: 3
...Temperature, pH, Enzyme Concentration , and Substrate Concentration on Catecholase Introduction Enzymes are biological proteins that speed up the reaction rate of a chemical reaction. They work in the human body by lowering activation energy making certain that reactions will initiate. For every action, there is an equal and opposite reaction. In this case, factors that influence the activity of an enzyme are called modulators. If modulators activate enzymes the reaction rate catalyzed will significantly increase, but if the modulator inactivates enzymes the reaction rate catalyzed will significantly decreased (Silverthorn, 2004). The potentially disastrous influence of temperature, pH, enzyme concentration, and substrate concentration on enzymes and other proteins is one reason why these modulators are very strictly regulated by the body (Silverthorn, 2004). Temperature, a measure of the intensity of heat, is an important factor in the activity of enzymes. The velocity of an enzymatic reaction is influenced by temperature. This is because substrates collide with active sites frequently in the presence of rapidly moving molecules. In addition, although these molecules do move rapidly the speed of the reaction drops sharply. In short, thermal agitation causes protein molecules (enzymes) to denature ( breakdown of protein structures). All enzymes have an optimal temperature at which reaction rates go fastest without denaturing the enzyme (Campbell and Reece, 2002) pH, a measure...
Words: 1991 - Pages: 8
...1025C Laboratory Exercise 3: Characteristics of Enzymes Introduction What are Enzymes? Enzymes are very large and complex proteins that that function as catalysts. They are synthesized by the cell to perform very specific functions. Each type of enzyme has a very specific shape (conformation) which provides its specific function. The shape of an enzyme molecule is determined and maintained by many weak intermolecular interactions between many different parts of the molecule. A catalyst is a material that donates energy to reactants in order to reduce their activation energy. In other words, they allow reactions to occur with less energy input (i.e. more quickly or at lower temperatures). The very specific shape of enzymes allows them to “fit” into a reaction and reduce the energy necessary for the reaction to occur. If their shape is changed, their ability to function as a catalyst is reduced or eliminated. As biological catalysts, enzymes are important because they speed up the rate of the reaction they catalyze that would otherwise be too slow to support life. Factors Affecting Enzyme Activity The rate at which an enzyme works is influenced by several factors including temperature and pH. Enzymes are most effective as catalysts under optimum physical and chemical conditions; as conditions change away from optimum, enzyme activity decreases (Figure 1.). Changes in various environmental factors, such as temperature or pH, may affect proteins by altering their shape; with loss of...
Words: 1552 - Pages: 7
... What is the effect of temperature, pH, and substrate concentration on Enzyme activity? Purpose: Enzymes are proteins that speed up chemical reactions in cells. They break down molecules called substrates. Each enzymes have only one substrate that breaks down. Enzymes are produced in the cells of the body and affect the rate of almost all the chemical reactions which take place in living organisms. The rate of enzymes activity is influenced by temperature, pH, and substrate concentration. The purpose of this lab was to determine the affects of enzyme activity under specific temperature changes, pH values and substrate concentration. Since heat increases the rate of most chemical reactions, the addition of heat causes faster molecular movement. Most enzymes active in living tissue becomes denatured, their secondary or tertiary protein structure breaks down, at the temperature above 40 degrees C. In the effects of pH, it is expected that the changes in pH would have an effect on the action of enzymes. Lemon juice helps keep the apple from growing, because its full of ascorbic acid (Vitamin C) and it has a low acidic pH level. But extreme high levels of low pH values can result in a complete loss of enzymes activity thus leaving the apple to brown. The effects of substrate concentration, an enzyme substrate complex is formed when a substrate fits into active of an enzyme. The velocity, the rate of speed, at which the enzymes works will increase until it reaches...
Words: 1327 - Pages: 6
...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...
Words: 2628 - Pages: 11
...The purpose of this experiment is to examine the effect that enzyme concentration has on reaction time and the effect that substrate concentration has on enzyme reaction. Enzymes are biological catalysts that catalyze different chemical reactions. In general, enzymes are proteins and they are each specific to specific chemical reaction. In order for enzymes to process properly, they should maintain a specific three dimensional structure. When enzymes function, they combine with their substrates (reactant) to form susbtrate-enzyme complex. Then this complex converts into a product and unaltered enzyme. Substrate + Enzyme Substrate-Enzyme Complex Product + Enzyme OR Substrate –Enzyme Product (From this equation, in general, the reaction of enzyme is irreversible.) Some of the factors that affect the rate of reaction are temperature, pH, enzyme concentration, substrate concentration, product concentration, etc. The rate of reaction is affected by the level of pH. The extreme level of pH can denature enzyme and result loss of its action. The optimum pH is 14 and this is the level of pH where the rate of reaction is the highest. Temperature also affects the rate of reaction. As temperature increases, the rate of reaction increases as well; however, it increases until the optimum temperature. After optimum temperature, the enzyme denatured. The concentration of enzyme and substrate affect the rate of reaction. In theory, the higher the concentration of substrate, the...
Words: 817 - Pages: 4
...Effects of Changes in Temperature, pH and Enzyme Concentration on Enzymatic Activities 1. Introduction Enzymes are biological catalysts that are protein. They speed up the rate of chemical reactions and metabolism in the body of organisms. They are specific in their action that means a certain enzyme will only speed up a certain reaction involving a specific substrate to bring about a specific product. Enzymes work on a key and lock mechanism where substrates are linked to their active sites. Enzymes reduce the activation energy required for reactions thus ensuring that reactions are more efficient in the sense that they use the least possible activation energy. Since enzyme are protein nature, changes in environmental conditions such as temperature and pH affects the structure of the enzyme’s active site and thus the activity of the enzyme which in turn affects the reaction in which the enzyme participates. Equally, the rate of enzyme activity is affected by the relative concentration of enzyme and substrate in the reaction mixture. This experiment investigates how the changes in temperature, pH and enzyme concentration affect the enzymatic activity of catecholase in potato juice extract (Biology 107 Lab Manual, 2011-2012 ed.) The presence of polyphenoloxides (PPO) in fruits and vegetables is one of the causes of change in color. Color is one of the most important attributes of food both for its aesthetic value and for quality. Minimally processed fruits and vegetables are...
Words: 490 - Pages: 2
...* Key Topics: * Explain and give examples of why proteins are essential to cell function * The basic structure of an amino acid * Describe the 4 levels of protein structure, and give examples of each * Explain what an enzyme is, understand why enzymes are needed to help chemical reactions, and know the role of the active site * Revisiting the Theory of Chemical Evolution * Modern life arose through a series of endergonic chemical reactions. 1. Production of small organic compounds * i.e., formaldehyde (H2CO), hydrogen cyanide (HCN) 2. Formation of mid-sized molecules from these small compounds * i.e., amino acids, simple sugars 3. Mid-sized building blocks combine to form large molecules. * i.e., proteins, complex carbohydrates 4. Life became possible when one of these large molecules self-replicated. * Organic Molecules * Large organic molecules are called macromolecules * Four major categories of macromolecules: 1. Proteins 2. Nucleic Acids 3. Carbohydrates 4. Lipids * Several of these are long chains of smaller subunits. * The smaller subunits are known as monomers * The long chains of monomers are known as polymers * Four groups of Macromolecules * Building Macromolecules – Monomers and Polymers * Molecules, such as amino acids, are individual units called monomers. They link together (polymerize) to form polymers, such as proteins...
Words: 1630 - Pages: 7
