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

Biology Coursework Enzymes

Extracts from this document...


Biology Coursework Aim To investigate how starch concentration affects an amylase-controlled reaction. Introduction An enzyme is a protein with a special shape, which catalyses or speeds up chemical reactions inside our bodies. However not all enzymes are proteins. The enzyme amylase that I will be using throughout my investigation to find out how starch concentration affects an enzyme controlled reaction is found in saliva in the mouth and also in the small intestine. Inside the body the enzyme amylase is used to break down the substrate starch into simple sugar (maltose), which is soluble in water. Enzymes are crucial to the existence of humans as it speeds up chemical reactions inside the body, which would be too slow in the absence of enzymes. Enzymes themselves only catalyse chemical reactions and do not alter the actual reaction, they also increase the rate of reaction. Enzymes have many properties which if affected can change the outcome of reactions taking place. When enzymes react the same end product is always formed. Enzymes themselves react best at the optimum temperature of 36.7 �C, as that is the general temperature of our bodies. Also enzymes have optimal pH levels as well at which they react best. The pH at which enzymes work best at is 7 (neutral). However exposure to heat over 40 �C or extreme pH (acid or alkali) can denature the enzyme, which will mean that they can no longer act as a catalyst for the reaction. Temperatures under 36.7 �C will not denature the enzyme but the reaction taking place will be considerably slower. The lock and key theory is a theory in biochemistry that looks at why enzymes catalyse reactions. The theory states that all enzymes have a unique shape and have a special active site on which the substrate attaches itself to and allows the enzyme to begin breaking down the food into products (nutrients). ...read more.


* Then I will place the blue/black starch solution into the test tube rack for ease and safety when adding the amylase to it. * I will then add the amylase to the 1% starch concentration, and immediately start my digital stopwatch. I will stop the digital stopwatch when the amylase turns the starch colourless. * I will then record my results in a table. I will then wash my equipment thoroughly and repeat each concentration twice for accurate and reliable results. I have made a dilution table, which I will follow to help me make the different concentrations. Dilution Table Starch Concentration (%) Amount of starch (ml) Amount of water (ml) 1 2 8 2 4 6 3 6 4 4 8 2 4.5 9 1 5 10 0 Fair Test I will make sure that the experiment I conduct will be accurate and reliable by checking and modifying certain variables before I start my experiment. Variables: Will I keep it constant ? Why ? How ? Temperature (�C) (controlled variable) Yes, I will keep this variable constant as temperature affects the rate of reaction at which enzymes work. If I keep this constant then the enzymes will work at the same rate in each experiment. Also if I do not keep the temperature constant then there is a chance that the enzymes can become denatured. I will use a hot water bath to keep the temperature of the water at a constant of 30�C so that the enzymes perform to the closest to there optimum temperature of 37�C (Body Temperature) Concentration of starch (%) (Independent variable) I will not keep this variable constant, as I have to change it for my experiment to be able to be conducted. By changing the concentration of the starch by adding more/less water and more/less starch I will be able to change the percentage of starch.. ...read more.


A second person would be able to start the stopwatch immediately whereas I had to try and pour the amylase into the starch and also at the same time try and start the stopwatch. All of these improvements would increase the reliability and accuracy of my results ensuring a better outcome Also I did not have any anomalous results as visible by looking at my graph. Conclusion In conclusion I personally think that the investigation was very successful. The predictions that I made proved to be right. I think that the reason my predictions proved to be right were partly because of the insight information I had received from the preliminary work I conducted, this helped me very much. Also my Introduction (see above) also led me to my prediction as I based it on the collision and lock and key theory. Also knowing about the properties of enzymes helped me to formulate a prediction. My results proved that as the concentration of starch increases the time taken for the amylase to brake down that starch decreases. It also proved that as the starch concentration increases the rate of reaction increases too I also noticed that there is a positive correlation between the starch concentration and the rate of reaction. This is because as the starch concentration increases there are more successful collisions between the enzyme's active sites and the starch particles creating more products. Enzymes are biological catalyst that speed up reaction. I think that the graphs I drew were quite good as well as they displayed correlation of some sort which backs up the prediction of what my graphs would look like. I think that my graph would have been better if I would have had more points to plot. To conclude I believe that the overall investigation was successful and I was able to investigate how starch concentration affects an amylase-controlled reaction. However I think that the experiment would have been better if the changes I pointed out in my Evaluation (see above) would be carried out. Mustafa Saai, 11P ...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

4 star(s)

****A well constructed procedure demonstrating good scientific knowledge.
The experiment was trialled and the procedure modified. There was a qualitative prediction supported by scientific evidence. The main error was the inclusion of an apparatus list which belonged to an entirely different experiment.
Carrying out
The candidate has presented the results of the pilot experiment and main experiment in a fairly clear and organized way. The range and number of repeats was acceptable.
Analysis and Evaluation
There was evidence of good processing of results- calculations of mean and rate of reaction. The conclusion was explained well using scientific theory. The student has considered the reliability of the evidence and made some sensible suggestions to improve the method. It might have been improved if another method could have been suggested such as the inclusion of a buffer to maintain pH and the measuring of colour using a colorimeter. The student does not have to have the equipment available to carry out a different technique.

Marked by teacher Stevie Fleming 01/01/1970

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

    Biology Coursework - Osmosis

    5 star(s)

    In my full experiment, I have decided to use the longer potato chips, since the more varying results will make the test more interesting, and also will make it easier to gauge the results because of the larger changes. Evaluation I think the preliminary experiment was both informative and successful.

  2. Marked by a teacher

    Potato / Osmosis Experiment.

    5 star(s)

    ISOTONIC VALUE Conclusion The strong negative correlation of the results is due to the fact that as sucrose concentration increases beyond the concentration of the potato plant samples, more water molecules from the potato plant samples are needed to dilute it by osmosis.

  1. Marked by a teacher

    Osmosis in Potato Chips

    5 star(s)

    them, meaning that the pressure was less inside than it was outside. This would cause the cell walls of the cells to be squashed inwards, thus making the potato chip floppy and soft. Can I be certain that my results justify my prediction?

  2. A investigation into the effect of inhibitor concentration on the enzyme catalase.

    expected to seen a gradual decrease in rate of reaction as inhibitor concentration increased. I.e. completely dilute solution -all distilled water) would've had the most reaction as there were no traces of lead nitrate acting as an inhibitor to slow it down, and so would be at the top.

  1. Investigating the effect of changing the concentration of an acid on the rate of ...

    measuring cylinder until the bottom of the meniscus reached the 4cm3 mark. 2. I would collect some 1.0M hydrochloric acid, and squirt it into the measuring cylinder until the bottom of the meniscus reached the 5cm3 mark. Safety In order to make sure the experiment runs smoothly, I need to

  2. See the effects of amylase on starch at different temperatures and to find at ...

    I have to keep these factors the same because if I use amylase with a high concentration for 30 degrees (1st experiment) and then amylase with a low concentration for 30 degrees (2nd experiment) I will get very different and inaccurate results.

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

    A secondary source is apple pomace and sunflower heads. Pectin is widely used in the food industry, principally in the preparation of gels. It is used as a base for jelly and as a stabilizer in some dairy products and frozen desserts, such as sherbet, and also as edible protective coatings for sausages, almonds, candied dried fruit, and soft dates.

  2. How Temperature Affects the Movement of Pigment Through Cell Membranes

    of the surface though we could clearly see the concentration got higher as the temperature increased - Each person used a different beetroot - The discs were cut from different parts of the beetroot - No instructions were given on how long to wash the beetroot before analysing - The water baths were not at the suggested temperatures.

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