• 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

To investigate whether the concentration of substrate (starch) affects the time taken for color change.

Extracts from this document...


´╗┐Strategy- Enzyme Concentration Investigate what Factors affect enzyme activity Enzymes are biological catalyst; they are responsible for chemical reactions in living organisms. Furthermore enzymes are proteins made of large molecules made up of long chains of amino acids, which speed up the chemical reaction in every living organism. The common model used to explain how food is broken down is called the lock and key model. The model consists of an active site, enzyme, and the product. An active site has a specific shape that whereby only another complimentary substrate can fit in. When the substrate has the matching shape it then fits into the active site. Then the enzyme speeds up the reaction, breaking down the substrate into 2 products. Now that the activation energy has been reduced to its minimum, the rate of reaction will escalate drastically. Sourced from Google images Factors that affect the rate of enzymes * Temperature- Enzymes have an optimum temperature of 37 degrees, the higher the temperature the faster the rate of reaction, but enzymes are proteins, and proteins at too high temperatures start to denature and therefore become inactive. * pH- Enzymes have an optimum pH (pH7), and if the pH is too high or too low the active site changes shape (denatures) ...read more.


My results were also affected by human error, as when adding iodine we were only meant to add 5 drops, but we added more. This was because the solution had not turned dark blue. Second Preliminary Hydrogen peroxide and Catalase On my second preliminary experiment, I decided to investigate whether the concentration of hydrogen peroxide changes the volume of gas created. The substrate is hydrogen peroxide and the enzyme is catalase. We first diluted the hydrogen peroxide with water, with concentrations of 25%, 50%, 75%; this gave us a wide range of results. Then we measured 5ml of catalase and 10ml of hydrogen peroxide. During the experiment I added 5ml of catalase and hydrogen peroxide with water consequently. Then I put the bung on and started the timer, and for every 10 seconds I recorded the amount of gas produced; I did this until 50 seconds. Amount of catalase(ml) Amount of Hydrogen peroxide +(water)(ml) Concentration of hydrogen peroxide Volume of gas 10sec 20sec 30sec 40sec 50sec 5 4+ 6 25% 0 3 5 5 6 5 5+ 5 50% 3 3 4 10 10 5 6+ 4 75% 2 2 2 2 2 My results show that using a concentration of hydrogen peroxide at 50% made the most gas, but the 75% concentration barley produced any gas and this told me that there barely was a reaction. ...read more.


* Boiling tubes- to hold our solution and allows us to have a more focused concentration of our enzyme. * Boiling tube rack- to hold our boiling tubes. * Stopwatch- to measure our measurements. * Measuring cylinders (10ml) - We chose to use the 10ml measuring cylinders because they have more intervals; allowing us to have more accurate results. * White paper- From our preliminary experiments we have learnt that if you keep a white paper behind the boiling tube rack then you can see when the solution has turned fully transparent. Method 1. Measure out 5ml of amylase in a boiling tube. 2. Using a pipette measure out 5ml of starch and 5ml of water (50%) in a separate boiling tube. 3. Add 7 drops of iodine to the starch using a buffer. 4. Then add the amylase to the blue starch solution. 5. Start timing on the stopwatch until the solution is transparent then stop. 6. Record your results of how long it took. 7. Carry on doing this with 5ml, 10ml, 15ml and 20ml of starch with 5ml of amylase each. I have worked out these concentrations because it gives me a good range of data. Risk Assessment Iodine- Harmful by inhaling and when in contact with skin. (Avoid contact with eyes, secure the lid firmly on the iodine, clean up ant spillages). By Mustafa Subhe ...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

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

    To investigate the effect of substrate concentration on Catalase Activity.

    3 star(s)

    The hydrogen peroxide will be out in a beaker to the required capacity is reached. A measuring cylinder will be placed upside down into a bowl and the tubing will be led into the measuring cylinder. The 3 potato discs will be put into a solution of hydrogen peroxide and the bung will be taken every minute for five minutes.

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

    Into a spotting tile put two drops of iodine into each well, using a pipette. 5) When the test tubes have been in the water bath for ten minutes, mix them together and start the stop clock. 6) Every fifteen seconds take two drops from the mixture and place

  1. Investigating the Effect of Substrate Concentration on Catalase

    Method * Collect all apparatus required * Put a piece of masking tape on the trough approx 3/4 of the way up and fill trough with water up to the bottom of the masking tape. * Set up the clamp stand so that the burette will be just above the bottom of the trough.

  2. To investigate the effect of the concentration of starch on an amylase controlled reaction

    If the pH levels are low, then the enzyme will not work to its potential. Amylase is the enzyme used to break down cooked starch into a simple sugar called maltose. To test if starch is present, iodine solution can be added, which turns a dark blue/black colour if there is starch present.

  1. I am going to investigate how a variable affects the rate of reaction in ...

    DATA: We had to decide on what data we were going to collect in our experiment. - Range of data: 5 different percentages of enzyme concentration - we chose this because it's sufficient data to produce a good graph from and interpret the trend and correlation.

  2. An experiment to investigate whether a change in the concentration of hydrogen peroxide substrate ...

    However if the temperature is too low, the energy and collision rate decreases, meaning the rate that oxygen is produced decreases. Another control variable is the Ph level. Ph measures acidity--water is neutral and has a pH of 7. Each enzyme has an optimum Ph level, this is mostly Ph7

  1. An Investigation into how the varying concentration of a substrate affects the rate of ...

    you increase the concentration of the substrate, the rate of reaction will be quicker because the more concentrated the molecules are, the more densely packed they are and so are more likely to collide and react. The rate of reaction will reach a plateau when there are higher concentrations because

  2. Structures and functions in living organisms. Revision Notes

    Pseudopodia surround the bacterium before the bacterium is enclosed in a vacuole where enzymes destroy it. Lymphocytes produce antibodies which specifically match a pathogen, attracting phagocytes or simply causing the pathogen to break open and die. Lymphocytes also produce memory cells which remain in the blood after the pathogen is

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