• Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month
Page
  1. 1
    1
  2. 2
    2
  3. 3
    3
  4. 4
    4
  5. 5
    5
  6. 6
    6
  7. 7
    7
  8. 8
    8
  9. 9
    9
  10. 10
    10
  11. 11
    11
  12. 12
    12
  13. 13
    13

Immobilized Enzymes (Yeast)

Extracts from this document...

Introduction

Immobilized Enzymes (Yeast) By Candidate Name: Poon Shun Yan Candidate Number: 1556 T2 Investigation submitted for Advanced Level Biology to EDEXCEL GCE, June 2005 Woldingham School, Centre Number 64030, Marden Park, Woldingham, Surrey, CR3 7YA Contents Abstract . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . p. 1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . p. 2 - 3 Method . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . p. 4 - 7 Data Analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . p. 8 - 10 Discussion and Evaluation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . p. 11 - 13 Abstract Catalase is an enzyme found in living cells and is used to break down peroxides. Yeast cells, which contain catalase, are used to catalyse the decomposition of hydrogen peroxide solution into water and oxygen gas. ...read more.

Middle

50cm3 burette will be chosen to collect oxygen bubbles because it has a narrow bore, and small graduations from which readings can be read off accurately. Predictions Increasing the number of alginate beads, i.e. yeast concentration with excess substrate molecules, the volume of oxygen collected should increases in direct proportion. The rate of reaction will also be directly proportional to the enzyme concentration. The reasons of both predictions are because there are more active sites available for the substrate to fit in which will be able to form more products: - Modification While investigating the rate of reaction on hydrogen peroxide solution, 5 alginate beads were first used. However no gas bubbles were produced in 5 minutes. Ten more beads were the added to start the experiment with 15 beads. Gas bubbles were produced very slowly. Thus the minimum number of beads for the investigation was set to be 15 and the experiment was repeated using the following number of beads: 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75 and 80. Risk Assessment Hazardous chemical or micro-organism being used or made, or hazardous procedure or equipment Nature of the hazard(s) Source(s) of information Control measures to reduce the risks Calcium chloride (a) Irritant to the skin and the membranes of eyes when contacted, and may cause asthma when inhaled (b) Dangerous with water under anhydrous salt can cause CLEAPSS hazcards Raising dust is avoided when making solution Hydrogen peroxide (a) Corrosive and causes burns if equal to or stronger than 5.9M (i.e. 20% or 71'vol') (b) Irritant if stronger or equal to 1.5M (i.e. 5% or 18 'vol.'), less than 5.9M and irritant to the eyes and skin (c) Explosive when contact with organic compounds such as propanone, ethanol, glycerol and many others. (d) Violent decomposition when contact with metals and metal oxides (especially if finely divided) and tin(II) chloride. (e) Dangerous if swallowed, may cause serious internal damage due to release of oxygen CLEAPSS hazcards The 20 vol. ...read more.

Conclusion

Percentage uncertainty Uncertainty value of the 50cm3 Grade B burette = 0.05cm3 Average volume Largest percentage uncertainty in volume of oxygen gas collected = 0.05/21 = 0.00238% (3 s.f.) The value is small enough to be ignored, which means the data obtained are precise enough. Improvements 1. A control experiment should be done when investigating the rate of reaction. The set-up should be the same but without adding any immobilized yeast. There might be a change of the burette reading after each time interval, since hydrogen peroxide decomposes easily into water and oxygen gas. The change of the reading should also be included in the table of result and should also be plotted on figures 4 and 5. 2. Under observation during the experiment was carried out, 1 bubble decreased about 0.2cm3 of the burette reading. This increased the time interval between each bubble. Thus some of the gas could not be collected at the time the reading was taken. A smaller internal diameter of delivery tube should be used to improve accuracy of the volume of oxygen gas produced. 3. New beads should be used each time as oxygen produced on the active sites of the enzymes did not fall off, which blocked the hydrogen peroxide substrate to fit in, and evidence was obtained from the purple line with 55 alginate beads which had proved the reliability of using new beads for each experiment. 4. Since the rate of reaction of catalase in the yeast cell is concerned in the experiment, only catalase should be immobilized instead of a whole yeast cell which will be more precise. NOTE: Chemistry investigation: change temperature, concentration of yeast is constant Gradient of rate against temperature, prove equation REF1: Central Team - BURTON G, HOLMAN J, LAZONBY J, PILING G, WADDINGTON D, (2000). Chemical Storylines. Heinemann Educational Publishers. [p.160 Fig.52] REF2: ADDS J, LARKCOM E, MILLER R, (2000). Molecules and Cells. Nelson Thornes Ltd. [p.45] REF3: SHEEHAN M, (1994). Biochemistry and Molecular Biology. Thomas Nelson and Sons Ltd. 1 Candidate Name: Poon Shun Yan Candidate Number: 1556 1 Candidate Name: Poon Shun Yan Candidate Number: 1556 ...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

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 concentration of enzymes affect the breakdown of starch by a-amylase in ...

    4 star(s)

    Firstly, the cork borer that was used did not have a totally smooth cutting edge. Due to this the circular holes bored will have had jagged sides. These jagged sides 'protrusions' contained in the jagged surface will increase the overall area of the reacting surface, which would cause the starch to break down slightly more rapidly than expected.

  2. Catalyse Investigation

    the enzyme substrate, they must be evaluated to find the rate of reaction in each of the conditions. A measure for the rate of reaction will be calculated by dividing 1 by the average time taken for the acidified potassium manganate solution to decolourise.

  1. To investigate the rate at which hydrogen peroxide is broken down by the enzyme ...

    This set-up as you can see is quite difficult and time-consuming to set up each time. This is mainly due to it being hard to prevent there being any gas in the top of the measuring cylinder before I start, because it is hard to completely remove all the gas.

  2. Investigate how concentration of the enzyme catalase in celery tissue alters the rate of ...

    To make a reading to within a millisecond or ten milliseconds would be hard to do with just my observation, so to be accurate to within a second is all we can possibly do. However, it can be done with specialist equipment.

  1. How do temperature and concentration affect the rate of decomposition of hydrogen peroxide by ...

    have to use a graduated pipette and take the volume I want out of the stock solution. There is also a more even distribution of the enzyme in the solution, than in the natural liver or potato samples, because it is constantly having air blown through it to keep it

  2. The Origin of the Mitochondrion.

    To ensure that all codons of mitochondrial protein-coding genes are translated properly, the missing tRNAs are imported from the cytosol (Lang et al. 1999). Since no similar tRNA genes are found in aerobic prokaryotes, the missing mitochondrial genes must have been replaced by genes in the nucleus, a process that was repeated several times during mitochondrial evolution.

  1. Investigating and analyzing the factors affecting the rate of decomposition of hydrogen peroxide by ...

    I am doing and what I intend to do for my actual practical. The results showed me that as the temperature goes higher the rate at which catalase works at increases, until the enzyme cannot work anymore. At this stage it is said to be denatured.

  2. An investigation into what happens when hydrogen peroxide is broken down by an enzyme ...

    As the temperature of the solution containing the hydrogen peroxide and catalase molecules increases so does the rate of reaction. This occurs because as the temperature increases the kinetic energy of the molecules also increases. As the molecules are moving around faster there are more collisions which lead to reactions between catalase molecules, and hydrogen peroxide molecules.

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