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

Investigation of the effect of the pH value on the enzyme controlled reaction

Extracts from this document...


Investigation of the effect of the pH value on the enzyme controlled reaction Background �A buffer is a mixture of a weak acid and a soluble salt of that acid. It is used to maintain the pH value of a solution. A weak acid can dissociate in solution to form H ions and the acid group ions. The concentration of the H ions decides the pH value of the solution. The H ions and the weak acid molecules are at an equilibrium state. If either of them increases the concentration, the reaction will go towards the side at which the molecules or ions with low concentration. To insure the solution with an almost constant pH value, the little amount H ions or OH ions should be removed if they are added to this solution. ...read more.


Neither too many nor too little is good for the shape of the enzyme (depend on the type of the enzyme). An enzyme with the distorted shape will not fit the substrate well so lose the ability to catalyse the reaction. As pH value gets higher and higher, the H ions get more and more and fewer and fewer enzymes can work properly. In consequence the rate of reaction is lower and lower. Safety a). Goggles essential as the solution with pH value 5 is irritant b). Almost all the enzymes all potentially irritant so avoid contact with skin. Apparatus 2 x Goggles / 10 x test tube / 6 x 2ml syringes / marker pen / 2 x iodine solution in dropper bottle (full) / 2 x stop clocks / 4 x spotting tiles / 1x thermometer / 4 x glass rods /10 x tissues Access to Starch suspension(1.0%)-about 25ml per group ( for wastage) ...read more.


6.Repeat step 5 for each pair of starch and amylase, record the time for amylase to break down the starch. Results pH at which reaction took place Time taken for amylase to breakdown the starch / s Personal results / reciprocals Average class results / reciprocals Personal Time Reciprocal *1000 Class average Average reciprocal*1000 4.0 1080+ 0.9 809 1.2 4.8 943 1.1 6.0 429 2.3 7.7 40 25 65 15.3 8.9 120 8.3 129 7.8 Note: To time the Average reciprocal is simply to make the value easier to read. Graph plotted on the graph paper Interpretations The graph shows as the pH value increases from 0 to around 7.7, the rate of reaction increases. As pH value increases from 7.7 to further, the rate of reaction decreases. This shows that amylase has an optimum pH around 7.7 (neutral). The interfering of the enzyme by H ions is described in the background. ...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 Aqueous Chemistry 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 Aqueous Chemistry essays

  1. Marked by a teacher

    The Effect of pH on the Strength of Keratin (hair protein).

    4 star(s)

    The alternative method of testing hair strength would be to draw the hair apart with hands, but this method means a difficulty in comparisons and also is very inaccurate. I will use a sample of a hundred (human, head) hair strands of the same hair type and of equal 20cm lengths.

  2. Investigating the effects of varying pH levels on the germination of cress seeds

    The 0% and 100% concentrations did not need bottles as I used the H2SO4 and H2O directly from the containers in which I received them (which were already labelled). I also labelled 2 of the 100cm� measuring cylinders with 'Sulphuric Acid' and 'Water' to prevent any accidental contamination.

  1. Calibrating pH meters

    Evaluation I will now evaluate my work to date be referring the aim set at the beginning of the assignment and will evaluate and analyse my performance and accomplishment the objectives. Aim: Within this experiment I will be using a Ph meter to identify the pH of three unknown substances.

  2. Establish what types of soil holds the most water and to see if changing ...

    Finally hands need to be washed with clean water after the experiment just in case a harmful substance has got onto the skin unnoticed and because germs can often breed in soil samples, again to reduce the risk of illness or injury.

  1. The action of amylase and pectinase in varying amounts when clarifying cloudy apple juice.

    2.7 2.7 6.4 0.3-0.7 2.7 2.75 6.4 0.2-0.8 2.75 2.75 6.4 0.1-0.9 2.9 2.9 6.4 Below is a graph of my results. Graph 1 shows more clearly the sudden drop in cloudiness towards the more equal mixtures of amylase and pectinase.

  2. Effects of immobilisation on the rate of reaction of an enzyme at different temperatures ...

    This is the number of substrate molecules which a molecule of the enzyme turns into product per minute. The turnover numbers of enzymes vary from 100 to several million; for the majority of cases it is approximately several thousand. One of the fastest enzymes is catalase, found in tissues where

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