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The effect that temperature has on the enzymatic activity of sucrase.

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INTRODUCTION. Enzymes are a biological catalyst, which speed up or slow down many chemical reactions. However, the enzyme itself will remain unchanged. Various temperatures can affect the rate of reaction. Enzymes are proteins constructed from chains of amino acid and are present in all living things. Living cells produce enzymes. They are specific in their action, they are a 3-dimensional molecule and work within a certain range of temperature; all enzymes have their own optimum temperature. The shape of the active site fits only one type of molecule so each enzyme controls a particular type of chemical reaction. Substrate binds to the active site to form on the enzyme substrate complex where the reaction takes place and the product is released leaving the enzyme free to work again. Sucrase is an enzyme and has an optimum (the temperature that promotes maximum activity) temperature of 37 0 c, and catalyses the breakdown of sucrose into its component monosaccharides (fructose and glucose). Reaction rates will increase as the temperature increases, since the temperature increases to its optimum rate (the rate at which an enzyme catalyses increases). However, this also increases the chances of the breakdown of the 3-dimensional structure of the enzyme. ...read more.


Thermometers are used and they may contain mercury (core spills). First aid kit must be available. Electricity and water is a very dangerous combination so take special care not to merge the two. APPARATUS 30 Test tubes (10 per concentration). 24x 1cm 3 syringes (8 per concentration). Test tube holder 2x5 cm 3 syringes Benedicts reagent 2x water baths (38 0 c and 50 0 c) Pen to write on glass. Measuring cylinder. Stop clock. Sucrase enzyme (1%). Sucrose solution 0.25%, 0.5%, 1% and 2%. METHOD 1. 10 test tubes were collected and labelled A, B and 1 to 8. 2. To tube A 5 cm 3 2% sucrose solution was added. 3. To tube B 5 cm 3 1% of sucrase enzyme solution was added. 4. To tubes 1 to 8 1 cm3 of Benedicts solution was added. 5. A and B were heated in a water bath at 380c for a period of five minutes to bring about equilibrium. 6. The stop clock was started B (sucrase enzyme) was poured into A (sucrose) this was swirled and returned back into the water bath. 7. At 30 seconds intervals 1 cm 3 was removed with a clean syringe and added to tube 1 8. ...read more.


25 %, 1.50%, 1.75% and 2%. These are of an even amount additionally; it would have given added points to plot on the graph rather than the three points that were plotted. Taking an average of all the amounts recorded in the experiments may possibly have represented a truthful representation of the data and if all four groups had carried out the full experiment. Furthermore with this being qualitative data it could have been difficult to agree on the exact colour that was seen, it is highly likely a human error occurred. Three people performing the experiment together could possibly have noted a colour that was not the accurate colour; this could be so in the experiment performed in the 0.5% of sucrose solution in the time period in the table of 150 seconds (pale green). Measuring the substrate sucrose with a pipette was not very accurate, using a better method of measuring the sucrose solution along with analysing the exact moment the enzyme worked on the substrate would have given a more accurate result. This experiment would have been enhanced had it been repeated using another method, which is superior to the method that was used on this occasion, for example weigh the precipitate or use a colour meter to assess the percentage light transmission. Rosina Wallis Biology Assignment (enzymes) 08/05/2007 1 ...read more.

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