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

Activity of starch synthase enzyme.

Extracts from this document...


Biology Experiment Report --Activity of starch synthase enzyme Introduction Enzyme is a protein that acts as a catalyst in biochemistry reactions. Enzymes speeds up biochemical reactions by lowering the activation energy-the minimum energy required for a chemical reaction to take place. With the presence of enzyme, the rate at which the reaction proceeds to form the product can greatly increase by a factor of up to 1020. Enzymes have several important properties: * They are specific. Each enzyme is specific to a particular reaction or group of similar reactions. For example, trypsin cuts an amino acid chain at a point between arginine and lysine, and nowhere else; amylase only attacks 2-glycosidic bonds but not other bonds. This can be explained by the 'lock and key hypothesis': each enzyme has an active site-the site on the surface of the enzyme molecule that binds the substrate molecule. The size, shape and chemical nature of the active site corresponds closely with a particular substrate molecule, so they fit together like a key fits into a lock, which means other substrates cannot react with the enzyme. * They have an optimum PH and temperature under which they can work most effectively. Most enzymes have an optimum PH of around 7 and an optimum temperature of around 30 C to 40 C (e.g. ...read more.


with glucose-a-phosphate at room temperature * Label 8 test tubes to receive 3 cm of 1% glucose-1-phosphate * Label 4 test tubes to receive 3 cm of 1% glucose * Label 12 test tubes to receive 5 cm of standard iodine solution * Label 12 miniature tubes to receive 1 cm of potato extract * When ready to begin the experiment, add 1 tube of potato extract to each tube of substrate. Note the time. * Immediately i.e. zero time tip one tube of the reaction mixture into a tube of iodine. The iodine denatures the enzyme and stains any starch present. * At intervals of 20 minutes tip another tube of reaction mixture into iodine. Repeat for a total of 4 tubes. * At the end of the experiment determine the amount of starch in each tube by reading the depth of colour in the colorimeter. Record the results and repeat the experiment for the other 2 treatments. * Plot light absorption against time for each experiment. The colorimeter consists of a light source, a filter to select the appropriate range of wavelengths, a photocell whose electrical resistance is proportional to the intensity of light falling on it, and a meter. The sample is then places between the filter and the photocell, a simple diagrammatic representation being given below. ...read more.


Accuracy can be improved by using a volumetric pipette. 2. One container was used for all the samples in the same experiment when using the colorimeter, so there were always a few drops from the previous sample left in the container, which might have affected the reading of the next sample. We can wash the container every time before reusing or use a new one for each sample. 3. The biggest source of error in the experiment was time controlling. * In step 6, I was required to immediately tip one tube of the reaction mixture into a tube if iodine. Whether I was slow of fast in this step might have affected the result. * I used a two-handed watch in the experiment, so I was unable to keep the intervals at exactly 20 minutes. A three-handed watch or even a stopwatch would be much more accurate. The method can be improved by interfacing the colorimeter to a computer to obtain a more accurate reading result. A further study could repeat the experiment at different time intervals and longer time, say 10 minutes for 2 hours, to give more data on the production of starch. Also different enzymes and substrates from different types of organisms (e.g. animals and bacteria) could be employed. The effect of different temperature and chemicals (acids and bases and some inhibitors) could be investigated as well. ...read more.

The above preview is unformatted text

This student written piece of work is one of many that can be found in our GCSE Life Processes & 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

3 star(s)

This is a well written report that has some good sections. However the investigation itself lacks direction.
1. The introduction is well researched, but the sources need to be referenced.
2. The hypothesis, equipment and method section all demonstrate good practice.
3. The evaluation is detailed and shows an understanding of scientific processes.
4. The investigation itself needs more direction. It would benefit from a preliminary test to determine the optimum temperature before the actual investigation is run.
***(3 stars)

Marked by teacher Luke Smithen 08/05/2013

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 GCSE Life Processes & Cells essays

  1. Marked by a teacher

    Isotonic Point of Potatoes

    5 star(s)

    * They did not bend very easily. * The colour was again a slightly lighter shade of yellow 0.3M - * The potato cylinders were quite soft. * They looked slightly smaller and shrunken then before * The colour was a light yellow * The potato cylinders could bend easily 0.4M - * The potato cylinders looked

  2. Marked by a teacher

    Osmosis in Potato Chips

    5 star(s)

    Record all results accurately. 8. Dispose of all equipment used safely and appropriately. Preliminary test results Mass of potato chip, g % of sucrose solution Mass after 2 hours, g Mass after 4 hours, g Mass after 6 hours, g 9.17 0 10.37 9.08 9.07 9.30 50 8.55 7.07

  1. Marked by a teacher

    Investigating Enzymes and the effects of different variables such as temperature on how they ...

    4 star(s)

    change, stopping them from reacting any more (I explain this in lots of detail further on). I will also keep the concentration of H2O2 the same as too high or low causes enzyme denaturing. I predict that the central temperatures such as room temperature shall have highest rate of reaction because there is only a small possibility of enzyme denaturing.

  2. Marked by a teacher

    To investigate the effect of temperature on enzyme activity. The enzyme used will be ...

    4 star(s)

    Repeat the experiment with temperatures of 10�C, 40�C, 50�C, 60�C, 70�C and at room temperature. To achieve 10�C place the test tube containing the hydrogen peroxide and buffer into ice until it reaches the temperature 10�C. Each experiment will be repeated three times for reliable results.

  1. What is the difference in Vitamin C content between orange juice and orange squash?

    The molecules of the orange squash DO in fact need to work hard in order to diffuse the DCPIP molecules, and more orange squash is needed in order to successfully decolurise the DCPIP solution. The following are two diagrams to explain this very process easier: If more orange juice or

  2. To investigate the factors that effect osmosis in living tissue.

    1 Concentration ==> % Change in Mass = k Concentration Most points correspond to the linear trend-line within an x and y-axis error margin of 5%. However, the point that seems least accurate is that obtained from the 0.1molar solution.

  1. The Effect Of Temperature On Anaerobic Respiration In Yeast

    I added hot and cold water whenever necessary in order to keep it at the temperature. This is not the most accurate way of keeping the water bath at one temperature, however it is fairly accurate and was one of few ways available to me.

  2. Experiment to investigate the effect of Temperature on the enzyme activity of Pectinase

    Non competitive inhibitor (non active site directed) - Where it attaches itself to another part of the enzyme which forces the enzyme to change shape. This basically slows down the rate if reaction by not allowing any substrate to attach onto the enzymes active site Different enzymes work on different substrates.

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