• Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month

The effect of temperature on the hydrolysis of starch using amylase extracted from barley.

Extracts from this document...

Introduction

Sasha Caddy, RM11. 20/01/04 The effect of temperature on the hydrolysis of starch using amylase extracted from barley Interpretation of results: Enzymes are a class of proteins that catalyse chemical reactions, which increases the rate of a metabolic reaction. Most enzymes are specific, working on a particular or class of reactions. In this case I am using an enzyme known as amylase (a group of enzymes which convert starch to sugar), which is an important metabolic enzyme. Amylase is found in various parts of the body including the saliva of the parotid gland and the pancreas, e.g. ptyalin, which aids in the digestion of carbohydrates by speeding up specific digestive processes taking place from the mouth to the small intestines. However, in this experiment we are using amylase which has been extracted from barley. The function of amylase is to catalyze (to modify the rate of a chemical reaction by catalysis) the hydrolysis (decomposition of a chemical compound by reaction with water) of starch into glucose. Starch is a mixture of two compounds; amylose and amylopectin, both of these molecules are polymers which contain a large, variable number of a-glucose molecules linked to each other by condensation. Amylase acts on starch, which is a polysaccharide (a class of carbohydrates; starch, consisting of a number of twenty-five monosaccharides) and breaks it down into maltose, a disaccharide. A disaccharide is defined as any class of carbohydrates; maltose, that yield two monosaccharides upon hydrolysis. ...read more.

Middle

This causes them to react more efficiently as this results in more enzyme-substrate complexes and in turn the formation of more products. At low temperatures e.g. 15 C, the molecules will not collide very frequently and the starch will not be broken down as quickly. This shown on the graphs at 15 C and at 0 minutes there is 0% transmission from the colorimeter, meaning that 0% of light can pass through the solution because there is 500mg of starch (shown by the 'Starch Calibration Curve'). As time increases to 22 minutes there is a 15% transmission from the colorimeter meaning there is 160mg of starch concentration left in the solution. This is because it has been broken down by amylase at a slow activity rate, so there is a higher concentration of starch left compared to the 25 C (120mg) and 35 C (70mg) results. From the second graph; 'A graph to show the milligrams of starch at minute intervals at different temperatures', it shows that with time, the starch concentration is decreasing for each temperature that is being tested. This graph shows an exponential decay curve of the amount of starch concentration broken down for every x minutes, therefore the substrate will not totally be broken down. This reaction is not a equilibrium reaction because as the starch concentration decreases the enzyme finds it increasingly difficult to find enough substrate to act on. From my results, I can conclude that between temperatures 15 C - 35 C, the efficiency of the enzyme increases with temperature. ...read more.

Conclusion

Another problem with the pipettes is that when the reaction medium was extracted and clearfully put into a diluted iodine solution, during this time the amylase was acting on the starch while this solution was in the pipette. This made the timings recorded slightly out, although this effect may have been lessened with the temperature at 35 C as the mixture was cooling down to room temperature in the pipette. Also we could have possibly swirled the enzyme extract and starch solution together in the water bath so that the substrate and enzyme could mix and the molecules collide. A solution to this whole experiment would have been to automate (convert to a automatic operation) the whole system. This would have allowed a sample of the mixture to be automatically taken every minute or possibly more frequently, and the concentration of the starch stored onto a computer. Carrying out the experiment like this would have solved any inaccuracies in timing, which may not have always been exact when using a stop clock and someone watching the time. This way it would have also removed any human errors e.g. the test tube not being wiped properly before being placed into the colorimeter or didn't shake the reaction medium and diluted iodine solution together enough/too much etc. So if the experiment had use of better apparatus and stricter conditions, my results would have been plotted onto a graph and a more clear and accurate curve would have resulted. In this experiment there were no anomalous results which can be shown from the graphs. ...read more.

The above preview is unformatted text

This student written piece of work is one of many that can be found in our AS and A Level Molecules & Cells section.

Found what you're looking for?

  • Start learning 29% faster today
  • 150,000+ documents available
  • Just £6.99 a month

Here's what a teacher thought of this essay

4 star(s)

****
This account includes detailed background theory and good discussion and evaluation sections. However, in places biological terminology might have been used more carefully.

Marked by teacher Adam Roberts 17/09/2013

Not the one? Search for your essay title...
  • Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month

See related essaysSee related essays

Related AS and A Level Molecules & Cells essays

  1. Marked by a teacher

    How does the pH affect the activity of amylase

    3 star(s)

    to wait for it, so at times assumptions were made that the pH was correct, so I would say that it could have affect my results although conclusions were still able to be drawn. Most of the errors made were systematic once as it was to do with measuring solutions

  2. Marked by a teacher

    Effect of temperature and inhibition on the rate of pepsin digestion.

    Results These graphs illustrate the results of our experiment. Some sets of results are not included because of error. First, no digestion occurred at 0'C, in view of the fact that our measurement was accurate to within � 0. 1 cm, but the amount of egg white eaten away was less than 0.1 cm.

  1. The Effect Of Temperature On The Action Of Salivary Amylase

    This can be denoted through the changes of color in the each test tube. If we reconnect what was said in the hypothesis "On the other hand we can also assume that enzyme activity can be more valuable when it is close to the body temperature".

  2. Qualitative tests for carbohydrates

    A positive result gives a dark blue-black product. (see fig.4 Iodine test positive result on the right) (www.wikipedia.org - Nov. 2007) e) Bial's test for Pentose - The test reagent consists of orcinol, hydrochloric acid and ferric chloride which dehydrates pentoses to form furfural.

  1. Investigation of the effect of adding different concentrations of NaCl to an enzyme-substrate (amylase-starch) ...

    The starch chains are chopped into smaller bits pieces. Glucoamylase, which can be a component of amylase, selectively attacks the last bond on the non-reducing terminals. It can act on both the alpha 1,4 and the alpha 1,6 glycosidic linkages, which therefore results in simple glucose units splitting off into the solution.

  2. An experiment to investigate the effect of chloride ion concentration on the activity of ...

    This in turn was then repeated for concentrations of chloride ions 0.05 mol.dm3 intervals until four identical endpoint had been recorded (e.g. 75 seconds). Further more the entire procedure was repeated to allow an average of two endpoints to be calculated for each concentration of chloride ions.

  1. An experiment to find of the isotonic point of root vegetables cells in contents ...

    0.7 these new concentrations will enable me to find the precise isotonic point. When the root vegetable is placed in the 0.3 molar sucrose solution I will expect the root vegetable to become turgid, because at this concentration the root vegetable will have a higher water potential and a lower solute potential.

  2. The effect of different temperatures on the movement of maggots.

    an optimum temperature of around 40�c due to enzyme activity in respiration. Diagram Apparatus * Glass tube, length approx 20cm * Two pieces of blue tack * Black paper + sticky tape * Tray * Water of varying temperatures * Lamp * Stop watch * 20 Maggots * Beaker The

  • Over 160,000 pieces
    of student written work
  • Annotated by
    experienced teachers
  • Ideas and feedback to
    improve your own work