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What is the effect of temperature on the reaction between sucrose and invertase

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What is the effect of temperature on the reaction between sucrose and invertase. About enzymes Enzymes are biological catalysts that speed up the rate of reaction without taking part, therefore causing the reaction to use less energy. They are all proteins so having either a primary, secondary or teritary structure ( how it is held together by globular proteins). These structures either build up (anabolism) or break down substances (catabolism). When these enzymes go past their optimum temperature which they work best at they become denatured. This is when the molecule is moving so fast due to very high temperatures that it vibrates so energetically that some of the bonds break causing the enzyme to change shape. At first the substrate just fits less well into the active site but then more bonds break causing the enzyme to loose it's shape more and therefore the more shape that is lost the longer and harder it is for the substrate to bind with the active site. This eventually causes the enzyme to become denatured. About sucrose It is a non-reducing sugar that is formed when C1 of the ? glucose and C2 of the ? fructose join in a condensation reaction. Therefore it is a disaccharide They are join by a 1-2 glycosidic bond. Both carbonyl groups occur within the 1-2 glycosidic bond so there are no free carbonyl groups to reduce the copper in the benedicts solution. Yet both fructose and glucose have a fee carbonyl group therefore can react with benedicts and are reducing sugars. ...read more.


measuring cylinders 1 to measure 5cm( of sucrose 1 to measure 5cm( of invertase - each time * Benedicts 18cm( for each part of experiment * 72 test tubes To hold sucrose and invertase To combine substances To filter into * 18 funnels To filter precipitate from the solution * 3 stirring rods To agitate solution while in water bath * Timer To time how long substances are in the water bath * 3 plastic droppers To measure and transfer sucrose, invertase and benedicts. * Test tube rack To hold test tubes * 90cm( of 2% sucrose It is the substrate we are using for testing * 90cm( of 2% invertase The enzyme being used to break down substrate * Balance To weigh out precipitate Method 1. Collect apparatus 2. Heat water bath to 30?c 3. Measure 5cm( of 2% sucrose into 1 test tube and 5cm( of 2% invertase and 1cm( of benedicts. 4. Put both in water bath for 5 minutes, time using timer. 5. Mix invertase and sucrose together and agitate using stirrer and put back into water bath for 30 seconds for time to react. 6. Add substance to benedicts and put back in the water bath for 5 minutes. 7. Remove from the water bath and filter the solution and leave to dry over night. 8. Repeat this for another 2 times at this temperature 9. Now repeat the whole thing for 40?c, 45?c, 50?c, 55?c and 60?c 10. ...read more.


* Also even though each solution of sucrose and invertase is stirred 4 times it is still a limitation as the rate and pressure can not be determined with the available resources. This may cause the rate of reaction to increase in some experiments as the molecules are agitated and therefore collide more often and therefore form more precipitate. Analysis As the results show that an increasing amount of precipitate is formed as does the temperature. This is due to the fact that the higher the temperature the faster the molecules move therefore the substrate (sucrose) collides with the active site of the enzyme (invertase) more often. This substrate binds with the active site then the invertase breaks down the sucrose into ? glucose and ? fructose. As they both are reducing sugars and can react with the benedicts due to the free carbonyl group the precipitate is formed. Therefore the higher the temperature the more precipitate formed as more frequent collisions are happening. However once the enzyme reaches its' optimum temperature, shown in the results as 55?c, the molecules start to vibrate so energetically that the bonds begin to break causing the shape of the active site to slowly change. The substrate is unable to bind with the active site as effectively causing the amount of precipitate to decrease and eventually become non-existent. The reasons that the precipitate produced increases as the temperature is due to the above as the molecules are starting to collide more often. ?? ?? ?? ?? Jodie Arlott 29/04/05 Biology Course Work ...read more.

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