Free Essay

Action of Enzymes

In: Science

Submitted By rajeshnair511
Words 1114
Pages 5
Action of enzymes as catalysts in biochemical processes

* Enzymes acts as catalyst and increase the rate of all the chemical reactions. * Enzymes are also described by two properties like all other catalysts. It composed of two main functions. * The first function is that, they increase the rate of chemical reactions by without consumed themselves or undergo any change or alteration in the reaction. . ( Zemitec et,al 2008). * The second function is, they increase reaction rates without changing the chemical equilibrium between the reactants and products. ( Bhagavan et,al 2006). * The reaction between two substrates are catalyzed by enzymes. The enzyme brings a template upon which the two substrates are combined together in the proper position and make them to react each other.
Deficiency in aldolase B and hereditary fructose intolerance * Hereditary fructose intolerance is a condition I which affects a humans ability to digest the fructose sugar. The incidence of hereditary fructose intolerance is 1to 2 in 20000 to 30000 individuals in a year worldwide. .( John .R.H 1996) * Hereditary fructose intolerance can be caused by mutations in the ALDOB gene. The ALDOB gene is responsible for making the aldolase B enzyme. The aldolase B enzyme is primarily seen in the Liver. This helps for the fructose metabolism. This enzyme is responsible for the further step in the metabolism of fructose, which breaks down the molecule fructose-1-phosphate into other molecules called glyceraldehyde and dihydroxyacetone phosphate. * The lack of aldolase B can results in the accumulation of fructose 1 phosphate in the liver. This seems to be toxic and can cause death of liver cells. The short of aldolase B can cause the reduction of dihydroxyacetone phosphate and this will lead to decrease in phosphate level in the body. ( Monique L 2008) * The damage of liver cells and a decrease level of phosphate groups will lead to hypoglycemia and will damage liver.

Specific substrate acted on by aldolase B during the breakdown of fructose * The specific substrate that acts on Aldolase B during the breakdown of fructose is fructose -1 phosphate (F1P). (Lowenstein j.m 1969) * This fructose 1 phosphate is further converted in to DHAP and glyceraldehyde. When the process is finished the product will enter the glycolysis cycle to make ATP or energy that can be used for body functions. * In normal cellular conditions, the primary enzymatic activity of aldolase B is to cleave fructose diphosphate (FDP).” (Roth, 2012)
Role of aldolase B in the breakdown of fructose * The ALDOB gene is responsible for making the aldolase B enzyme. The aldolase B enzyme is primarily seen in the Liver. This helps for the fructose metabolism. This enzyme is responsible for the further step in the metabolism of fructose, which breaks down the molecule fructose-1-phosphate into other molecules called glyceraldehyde and dihydroxyacetone phosphate.( John .R.H 1996) * After glyceraldehyde is added by a phosphate ,i.e. by triose kinase to form G3P, can be used in the glycolytic and gluconeogenic pathway, and can be modified in to glucose or pyruvate. * The enzyme helps the chemical reaction to be speed up with minimum error. It is happen by lock and key process where as enzyme is key and substrate is lock. ( Monique L 2008)
ATP and Cori cycle * The Cori cycle , otherwise called as lactic acid cycle is the metabolic pathway in between the lactic acid produced as a result of glycolysis move to the liver and it is converted in to glucose and then comes back to muscles and made back to lactose. (Nelson 2005) * The lactate is accumulated in the liver instead of keeping it in the muscles. Then makes the second mode of Cori cycle, ie gluconeogenesis will start in the liver. * This reverses the glycolysis and fermentation by first converting lactate into pyruvate and then to glucose. * The part of glycolysis produces two ATP molecules. This is produced by consuming 6 ATP molecules in the glycogenesis part. In this stage each stage is maintained by consuming at least 4 ATP molecules. So the cycle cannot be sustained clearly. * This indicates that the Cori cycle reduces the metabolic efforts of muscles to the liver. (www.
Citric acid cycle * Glycolysis is a metabolic process that pyruvate and hydrogen is formed from glucose and glycogen. The pyruvate is converted into acetyl – coenzyme A. For this process enough oxygen is needed. So if the oxygen is sufficient the acetyl coenzyme A then goes on to Krebs cycle or citric acid cycle. (Lowenstein j.m 1969) * As a result of Krebs cycle or otherwise called as electron transfer chain the ADP is converted in to ATP. For this process also there should be sufficient oxygen is needed. * The process by which by using oxygen the ADP is converted into ATP is called as oxidative phosphorylation. * If there is not sufficient oxygen the production of ATP will be less and as a result lactose will be formed as a byproduct. * Because of this proteins will accumulate and will result into acidosis. ( Monique L2008) * If the enzyme called citrate synthase is unable to perform its function a hypothetical defect can happen and it affects the overall production of ATP. The citric acid cycle cannot be finished if the citrate cycle is affected. The citrate synthase has its own role in creating a COA ,which joint with pyruvate and forms acetyl COA. The acetyl COA initiates the citric acid cycle and produce ATP *
Role of coenzyme Q10 in ATP synthesis
The coenzyme Q10 is fat soluble and this is soluble and movable in the cellular membranes. This plays an important role in Electron Transport chain. The electrons from NADH and succinate moves through the electron transport chain to oxygen and further moved out to water.( Bhagavan et,al 2006). This occurs in the inner cellular membranes. The movement of electrons through the ETC will results in H+ pumping and make a proton gradient crossing the membranes. This will used by ATP synthase to release ATP.
The coenzyme Q10 acts in the role of electron carriers starting from enzyme complex 1 to 2 to 3 during the entire process. The coenzyme Q10 acts in each and every cells to make energy.( Zemitec et,al 2008).
John R Holum, 1996, 2nd ed, organic and biological chemistry, von Hoffman press.
Monique Laberge phd,2008, 1st ed, essential chemistry, Chelsea house publications.
Nelson David, 2005, 1st ed, principles of biochemistry, WH freeman company. www. Cori /cycle
Lowenstein J.M, 1969, 1st ed, citric acid cycle, Boston academic publication. Bhagavan et al, 2006, 1st ed, coenzyme Q10, intake and absorption, free radical research.
Zmitek et al, 2008, improving bioavailability of coq10, Agro food IND.

Similar Documents

Premium Essay

Lop of Lop indicated by ... Experiment: investigation of action of saliva and hydrochloric ... Jun 25, 2012 - 1) Name of enzyme involved 2)specific action(s) of enzymes involved. Two hydrolytic enzymes and an epistemological–historical ... Science in School Sep 3, 2007 - 5 M sodium hydroxide (NaOH); 5 M hydrochloric acid (HCl); Saliva. ... To demonstrate the test methods, test all four carbohydrate solutions ... Discussion ... more concentrated than is necessary for the activity and that using a ... The authors have recommended the Fehling’s test for this investigation. What is the objectives of investigation of action of saliva and ... › Wiki Answers › Categories › Science › Biology ... of investigation of action of saliva and diluted hydrochloric acid in two ... to determine the type of carbohydrate ... Action of saliva in carbohydrate solution? Action of saliva in carbohydrate solution - › ... › Carbohydrates and Low-Carb Diets Which enzyme present in saliva helps in digestion of carbohydrates? .... of investigation of action of saliva and diluted hydrochloric acid in two carbohydrate ... Free enzymes investigation Essays and Papers Then add two drops of Iodine (to test if starch is present-the solution will go ... This enzyme is produced by the salivary gland. .... Plants......

Words: 799 - Pages: 4

Free Essay


...Temperature Role of Enzymes * Metabolism – All of the chemical processes occurring within an organism * Chemical activity is maintained by large proteins – Enzymes * Enzymes: * Protein molecule that acts as a biological catalyst * Speed up rates of reactions * Their action is specific: catalyzing only one type of reaction * Used over and over in small quantities * Made in cell when they’re needed * Most work effectively at 37°C Functions and Characteristics of Enzymes * Catalysts control the rate of reaction – speed it up or slow down – but they’re chemically unchanged at the end of the reaction * Enzymes work by providing a surface or active site (The surface of an enzyme where the catalyzed reaction occurs) where the reaction can occur. * Substrate – a molecule/substance that is affected by the action of a catalyst such as an enzyme * It binds with the active site * The binding changes the shape of the active site and enzymes – Induced fit – temporary change in the shape of the enzyme, that binds an attached substrate more strongly too it. * Chemical reaction occurs and substrate is changed * In increase in substrate concentration will increase the rate of reaction until all the enzyme active sites are occupied (Saturation Point) – it’ll then proceed at its maximum rate * Activation Energy – Is the least amount of energy needed for a chemical reaction to take place Two Models for enzyme......

Words: 374 - Pages: 2

Premium Essay


...the action of 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......

Words: 2628 - Pages: 11

Free Essay


...|Physical Digestion |Mechanical breakdown of food into small particles which increases the surface area to volume ratio so that| | |digestive enzymes can act on the food more efficiently | | |Achieved by teeth, tongue, stomach walls | |Chemical Digestion |Enzymatic hydrolysis of large food molecules such as proteins, starch and fats, into small soluble | | |molecules, which can be absorbed. | | |Achieved by digestive enzymes in the mouth, stomach, duodenum and ileum. | B) THE HUMAN ALIMENTARY CANAL (memorise all structures!) C) WHAT IS PERISTALSIS? • Definition: Peristalsis is the rhythmic wave-like contractions of the gut walls caused by the action of two antagonistic muscles (circular and longitudinal muscles). It moves the food along the gut and mixes it with digestive juices. [pic] • Antagonistic muscles = a set of 2 muscles that opposes the action of one another to bring about movement. (When 1 muscle contracts, the other relaxes and vice versa.) • When the circular muscles contract, the longitudinal muscles relax (......

Words: 1348 - Pages: 6

Premium Essay

Unit 4.2

...M1-Discuss the Roles of Energy in the Body In this assignment I will be explaining the physiology of the cardiovascular system and the respiratory system. Whilst explaining the two body systems I will be explaining energy production, process of cellular respiration, the role of enzymes within these body systems, the way that these systems absorb food and the products of digestion. The Cardiovascular System The heart pumps the blood around the body through the blood vessels which is made of mostly veins and capillaries. The blood carries the dissolved oxygen around the bodily cells, whilst carrying the dissolved oxygen the blood removes the waste and the other products from respiration. The body’s blood pressure has to be maintained. The blood distributes heat around the body along with hormones, nutrients, salts, enzymes and urea. The cardiovascular system transports simple molecules and materials to the liver and the body cells via the blood stream. This happens through the hearts pumping actions. The Respiratory System The respiratory system always refreshes oxygen within the lungs, it gets rid of the waste products like carbon dioxide and water, and this is done throughout actions like breathing. The dissolved oxygen passes through the alveolar walls into the bloodstream; this is then transported into the cells. Body cells are persistently being made into raw materials such as glucose and other nutrients like dissolved oxygen. This happens so the......

Words: 2740 - Pages: 11

Premium Essay

Effect of Temo on Catalase Expirement

...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......

Words: 310 - Pages: 2

Premium Essay


...Enzymes An enzyme is a protein molecule that helps to increase the rate in which chemical reactions occur. Recognizing an enzyme is very simple as they are named after a substrate with the suffix “ase” attached to the end. In terms of activation energy, an enzyme’s function is to decrease the amount of energy necessary for the reaction to take place. An enzyme inhibitor prevents that function from happening by binding to the enzyme. There are two different ways that enzyme inhibition can occur. The substrate imposter can either bind directly to the active site so the real substrate cannot bind or it can bind to a different site other than the active site. When it binds to another site it causes the enzyme to change its shape, therefore not allowing the real substrate to be accepted into the active site. Two different theories exist that explain how substrates fit into the active site of an enzyme. First is the Lock and Key theory which states that a substrate (key) fits into the active site of an enzyme (lock) perfectly without any change of shape of the active site at all, according to Elmhurst College’s virtual chemistry book. This theory differs from the Induced Fit theory, which states that when a substrate binds to the active site, the active site’s shape slightly changes to perfectly fit the substrate. Just like a protein, the class of macromolecule that an enzyme belongs to, the function of an enzyme depends greatly on its tertiary structure. If the structure of......

Words: 424 - Pages: 2

Free Essay

Chapter 6 Outline

...ioChapter 6 Metabolism: Energy and Enzymes The nature of energy and the laws of thermodynamics are discussed, followed by a detailed description of energy transformations that occur within the cell. The chemistry and functions of ATP are described. The role of enzymes in metabolism, oxidation-reduction reactions, and the cellular organelles in which these reactions take place are detailed. Chapter Outline 6.1 Cells and the Flow of Energy A. Forms of Energy 1. Energy is capacity to do work; cells continually use energy to develop, grow, repair, reproduce, etc. 2. Kinetic energy is energy of motion; all moving objects have kinetic energy. 3. Potential energy is stored energy. 4. Food is chemical energy; it contains potential energy. 5. Chemical energy can be converted into mechanical energy, e.g., muscle movement. B. Two Laws of Thermodynamics 1. First law of thermodynamics (also called the law of conservation of energy) a. Energy cannot be created or destroyed, but it can be changed from one form to another. b. In an ecosystem, solar energy is converted to chemical energy by the process of photosynthesis; some of the chemical energy in the plant is converted to chemical energy in an animal, which in turn can become mechanical energy or heat loss. c. Neither the plant nor the animal create energy, they convert it from one form to another. d. Likewise, energy is not destroyed; some becomes heat that dissipates into the environment. ...

Words: 1545 - Pages: 7

Free Essay


...Enzymes • The secret ingredient in living organism is Catalysis, a process performed by protein enzymes. • Their three-dimensional architecture gives them exquisite specificity to select the substrate molecules to which they will bind and on which they will operate. • The scene of operation called “active site” is usually a groove ,cleft or cavity on the surface of the protein. • Enzyme function frequently occurs many times, and in some cases many thousands of times per second. • The miracle of life: a myriad chemical reactions in the cell occur simultaneously with great accuracy and at astonishing speed. • Without the proper enzymes to process the food you eat, it might take you 50 years to digest your breakfast. • Catalysis is probably the most important function of proteins. • Catalysts that serve this function in organism are called enzymes. • With the exception of some recently discovered RNAs that have catalytic activity, all enzymes are proteins. • Enzymes are the most efficient specific catalysts known (increase rate reaction up to 10²º). • Nonenzymatic catalysts (up to 10²-104). • Enzymes are highly specific,even to the point of distinguishing stereoisomers of a given compound. 1)Enzymes are Effective Biological Catalysts 2)Difference between Kinetic and Thermodynamic Aspects of Reactions • The rate of the reaction and its thermodynamic favorability are two different topics although so related. • The standard free energy change (ΔG°) is the......

Words: 1759 - Pages: 8

Free Essay


...Furnace/oven 8. Flame photometer 9. Charge analyzer ABSTRACT This review highlights the progress of application of Xylanase Enzyme in refining which includes the mechanism of action and its effects on Hard and Softwood pulp. Refining is a papermaking process where the cellulosic fibres are mechanically treated, resulting in morphological and structural changes to produce desired fibre properties for a better quality paper. Refining requires a large amount of energy and is performed in beaters or refiners. Due to high energy requirement and problems related to fines generation by the conventional refining process, use of enzymes especially the cellulases and hemicellulases is gaining popularity, and here Xylanase is taken to see its effects on refining. Enzymes are valuable in order to develop better fibrillation for better quality of paper, saving electrical energy, and improved drainability of pulp. But, there is a limitation of using enzyme in that it can reduce the pulp viscosity. The enzyme is added to the pulp, in the pulper, and given an appropriate reaction time to perform its particular action on pulp. Then the sample is taken at different time intervals, diluted with distilled water, consistency and SR is calculated and sheets are made to observe the effect of enzyme on the raw material. The physical properties of the sheets showed variations in values of sheet strength. The strength was increased in some sheets and......

Words: 5854 - Pages: 24

Premium Essay

Biol Lab Relationship Between Salivary Amylase & Phosphorylase

...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

Free Essay

The Test

...1. BIOCHEMISTRYLABORATORY(Midterm)Geromil J. Lara, RMT, MSMT 2. ACTIVITY 1A /1B Subcellular Components of the Living Cell• 5% Trichloroacetic Acid – Suspending medium – Able to precipitate proteins – Good fixative and preservative 3. ACTIVITY 1A /1B Subcellular components of the Living Cell• Sediment 1 – Nuclear Fraction – Nuclei and Unbroken Cells• Sediment 2 – Mitochondria• Sediment 3 – Microsome – Proteins, Enzymes, Inorganic Ions 4. ACTIVITY 1A /1B Subcellular components of the Living Cell• Qualitative Tests – Carbohydrates • Molisch Test • Benedict’s Test – Proteins • Biuret Test • Xanthoproteic Test – Lipids • Sudan Test • Acrolein Test 5. ACTIVITY 1A /1B Subcellular Components of the Living Cell• Carbohydrates – Molisch Test 5 drops of the supernate + Molisch Reagent shake Layer with 1 mL conc. H2SO4Control: 1% LecithinMolisch Reagent: α-Naphthol dissolved in Ethanol 6. ACTIVITY 1A Subcellular components of the Living Cell• Carbohydrates – Molisch Test 5 drops of the supernate + Molisch Reagent shake Layer with 1 mL conc. H2SO4Principle: when sugar solution is mixed with alpha- naphthol is brought in contact with conc. H2SO4, a violet ring is formed at the junction of the 2 liquids 7. ACTIVITY 1A Subcellular components of the Living Cell• Carbohydrates – Molisch Test 5 drops of the supernate + Molisch Reagent shake Layer with 1 mL conc. H2SO4H2SO4 : acts as dehydrating agent forming furfural derivatives which interact with alpha-naphthol liberating a colored......

Words: 2072 - Pages: 9

Premium Essay


...done by enzymes. If you understand enzymes, you understand cells. A bacterium like E. coli has about 1,000 different types of enzymes floating around in the cytoplasm at any given time. Enzymes have extremely interesting properties that make them 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. At the most basic level, a cell is really a little bag full of chemical reactions that are made possible by enzymes! Enzymes are made from amino acids, and they are proteins. When an enzyme is formed, it is made by stringing together between 100 and 1,000 amino acids in a very specific and unique order. The chain of amino acids then folds into a unique shape. That shape allows the enzyme to carry out specific chemical reactions -- an enzyme acts as a very efficient catalyst for a specific chemical reaction. The enzyme speeds that reaction up tremendously. For example, the sugar maltose is made from two glucose molecules bonded together. The enzyme maltase is shaped in such a way that it can break the bond and free the two glucose pieces. The only thing maltase can do is break maltose molecules, but it can do that very rapidly and efficiently. Other types of enzymes can put atoms and molecules together. Breaking molecules apart and putting molecules together is what enzymes do,......

Words: 598 - Pages: 3

Premium Essay


...PRACTICAL REPORT NAME | Dylan Yong Chun Yen | PARTNER’S NAME | Ng Cheau Wen | PRATICAL GROUP | PG 15 | DATE OF PRATICAL SESSION | 18th June 2014 | PROGRAMME | Foundation in Science ( P stream ) | UNIT CODE | FHSB 1214 | UNIT DESCRIPTION | Biology I | YEAR &TRIMESTER OF STUDY | 2014 Trimester 1 | TITLE OF LAB REPORT | Practical 3: Investigation of Action of Saliva and 3M Hydrochloric Acid in Two Carbohydrate Solutions | LECTURER’S NAME | Ms. Bong Siew Mee | Title: Investigation of Action of Saliva and 3M Hydrochloric Acid in Two Carbohydrate Solutions Objective: To investigate the action of saliva and 3M hydrochloric acid in two carbohydrate solutions. Results: Table 1: Observations made when two carbohydrate solutions provided in laboratory were tested with Benedict and Iodine solution. | Observations | Conclusions | Solution A | Benedict’s test: An initial blue translucent mixture turned to brick-red opaque solution and moderate amount of precipitate settled after heated at a high temperature for two minute. | Presence of reducing sugar | | Iodine test: The translucent colouration of the mixture retained its yellowish-brown colour. | Absence of starch | Solution B | Benedict’s test: The translucent colouration of the mixture remained its blue......

Words: 992 - Pages: 4

Premium Essay

Milk Processing

...color to whey. With all of the five factors described we will now move on the chemical side of milk. Milk has many natural enzymes; other enzymes are produced from bacteria growth. According to Encyclopedia Britannica “Enzymes are biological catalysts capable of producing chemical changes in organic substances. (1)” Enzymes in milk are very important. Enzymes control the flavor and body of different milk based products. Such important enzymes are “Lipases (fat-splitting enzymes), oxidases, proteases (protein-splitting enzymes), and amylases (starch-splitting enzymes) are among the more important enzymes that occur naturally in milk. (Britannica 1)”In addition to “the proteolytic enzyme (i.e., protease) rennin, produced in calves’ stomachs to coagulate milk protein and aid in nutrient absorption, is used to coagulate milk for manufacturing cheese.( Britannica 1)” The coagulation of milk is important Encyclopedia Britannica explains: The coagulation of milk is an irreversible change of its protein from a soluble or dispersed state to an agglomerated or precipitated condition. Its appearance may be associated with spoilage, but coagulation is a necessary step in many processing procedures. Milk may be coagulated by rennin or other enzymes, usually in conjunction with heat. Left unrefrigerated, milk may naturally sour or coagulate by the action of lactic acid, which is produced by lactose-fermenting bacteria. This principle is utilized in the......

Words: 1434 - Pages: 6