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

    plus iodine turned from a clear solution to a dark blue color. The solution (Salvia + Starch) plus iodine turned from being a clear solution to a light blue color. The solution (Salvia + Starch) plus iodine was not 100% accurate because of the failure to wait until time limit

  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. Type - 1 Hypersensitivity Reaction

    contracted, the histamine possibly was not only bound to the H1 receptors but quite likely bound to the H2 receptors as well. It seemed evident that the shot of histamine from outside the guinea pig ileum also creates a contractile response that occurs via histamine binding on the H1 receptors.

  2. Acid Hydrolysis of Polysaccharides.

    The highly branched structure is important for the metabolism of the glycogen molecule, as it maximises the surface area available for reaction, while its spherical shape allows the molecule to travel unimpeded through the blood, and not 'snag'. Amylose Amylopectin Glycogen Cellulose Aim: To compare the hydrolysis of glycogen, starch and cellulose.

  1. DETERMINING THE WATER POTENTIAL OF A POTATO TUBER CELLS USING THE WEIGHING METHOD.

    This would not have given very accurate results for my pilot study. I predict this to happen because of osmosis. If the two water potentials of two systems either side of a partially permeable membrane are the same, then there will be equilibrium and there will be no net movement of water molecules.

  2. The investigation to find the effect of glucose concentration on fermentation of yeast.

    the ionic bonds in enzymes, both of which can denature the enzyme * Respiration involves a number of enzymes, which, work with a number of substances in order to make ATP. In order for ATP to be successfully made there are a number of chemical reactions that occur.

  1. Investigating how different concentrations of a antibiotic effects the growth of a bacterium.

    So in final conclusion it can be seen that the increase in the concentration mean that the binary fission process is less likely to be complete due to the cell wall synthesis inhibition. Therefore the greater the concentration percentage, the more inhibition is likely to occur and the grater the area surrounding the saturated discs will be.

  2. To Investigate an Enzymes Reaction.

    When I am ready I will add the substrate to the catalase and start the stopwatch. 3. Record every 20 seconds how high the bubbles (of foam) have gone and record this in the table. 4. Repeat 3. and 4.

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