IB Biology Lab report

Biology HL Internal Assessment

The effect of different temperature of homogeneous mixture consisting of distilled water and Agaricus bisporus on enzyme activit y?

School name: ********************* ********************** * Candidate name: Agnes ********* Candidate number: *********

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Candidate number: ******-006

Research question: What is the effect of different temperature of homogeneous mixture consisting of distilled water and Agaricus bisporus on enzyme activity?

Background information:

Enzymes are globular proteins, which speed up reaction without being changed themselves. Without them, the reactions would be very slowly and nothing would control the reactions. ’’Enzymes are nearly always proteins, though they may contain non -protein component.’’1 The main properties of enzymes are: 

Work rapidly.



Work in both directions.



Speed up reactions.



Are dependent on pH, temperature and substrate concentration.



Can be reused. With the increase of temperature, enzyme activity increases too. The phenomena

occurs until the reaction obtain the optimum point, where the temperature is so high, that increased a little more will damage the enzyme’s structure. ’’At this point, the enzyme ceases to function; a phenomenon called enz yme or protein denaturation. Extremes in acidity (pH) can also cause the protein structure of enzymes to denature. Poisons often work by denaturing enzymes or occupying the enzyme’s active site so that it







Candidate number: ******-006 does not function. In some cases, enzymes will not function without cofactors, such as vitamins or trace elements.’’2 One of the fastest enzyme is catalyse. This enzyme is found in number of organs and tissues, including the liver where its job is to speed up decomposition of hydrogen peroxide into oxygen and water: 2 H2O2 → 2 H2O + O2

Enzyme activity is the quantity of active enzyme present and is thus dependent on conditions, which should be specified. Optimum temperature of enzyme is the temperature at which enzyme activity is the fastest.

Agaricus bisporus is more known as white mushrooms and is the most popular type of mushroom in the word. It has surprisingly high nutritional values and is excellent source of protein and plenty of vitamins and minerals.3







Candidate number: ******-006 Picture 14 Picture presenting the nutritional values in 100g of white mushrooms.

Hypothesis:

According to the background information, the temperature has a big influence on the rate of reaction and therefore on enzyme activity. Increases the temperature of the







Candidate number: ******-006 its optimum point – temperature temperature at which it works the fastest. If temperature will increase above the optimum temperature, protein will start to denature and the rate of the reaction will decrease. Finally the protein will be damaged completel y and no reaction will occur.

Variables:



Independent: 

Temperature of the homogeneous solution. The temperatures will be as follows:     and  .



Dependent: 

High of the foam produced after adding 3% hydrogen peroxide into homogeneous solution at different temperatures.



Controlled: 

One source of Agaricus bisporus.



One source of distilled water.



The same size and type of test tubes. This will eliminate a source of error during the process of measuring the high of the foam produced.



Once prepared homogeneous solution for all trials. This will eliminate a source of error, because every trial will the same ratio of Agaricus bisporus to distilled water.



One source of distilled water, distilled water from one bottle.



Careful timing. In this experiment, we wait just only for 5 seconds before taking measurements. This requires focus and high precision. Good stopper will be essential.



The same temperature. Conducting trials for one temperature of homogeneous solution, before putting the next test tube to hot water bath, the temperature of the bath must be checked. What is more, the use of polystyrene cup in which beaker with hot water is placed, will decrease the change of temperature.



The same laboratory conditions, e.g. no change in light light intensity, temperature.



The same source of 3% peroxide.








Apparatus and materials: 

300 cm3 beaker.



200cm3 beaker with lid.



Polystyrene cup for 300cm 3 beaker.



Bursen burner.



Noncontact digital infrared thermometer laser with accuracy  .



Electronic balance with accuracy 



1cm3 pipette with accuracy  



10g of Agaricus bisporus.



100g of distilled water.



Blender.



Marker.



50 the same type of test tubes.



Stopper.



50cm3 of 3% hydrogen peroxide in a bottle with tip.



Ruler with accuracy .



Rubber gloves.



Tweezers.

Methodology: I.

Label test tubes.

II.

Make a homogeneous solution by mixing 10g of Agaricus bisporus with 100cm 3 distilled water. To measure the volume of water, put the blender on the scale, tear the scale and put into the blender 100g of water ( 1cm 3 = 1g).

III.

Pour homogeneous solution into 200cm 3 beaker and cover cover it to prevent water loss from the mixture.

IV.

Using pipette pour 1ml of homogeneous solution into first tube.

V.

Pour 200g of water into 300 cm 3 beaker and check the temperature using noncontact digital infrared thermometer laser. We want the temperature to be   .









Candidate number: ******-006 b) In a case, that the temperature is too low, heat water using Bursen burner to

obtain desired one. VI.

Place beaker with water into polystyrene polystyrene cup. This will help to slow the heat loss/ gain from environment. This will make experimental results more accurat e.

VII.

Put the first test tube into water bath and wait for three minutes. Measure the time with the stopper, to avoid mistakes.

VIII.

After 3 minutes, the homogeneous solution get the temperature of the water bath. Immediately take out the test tube and add 3 drops drops of 3% hydrogen peroxide.

IX.

Wait 5 seconds and using ruler measure the height of produced foam.

X.

Record the data and again put 1 cm 3of homogeneous solution into the next test tube.

XI.

Check the temperature of water bath and if the temperature changed and: a) If it is too high place the beaker in freezer and keep checking the temperature until

it will be desired one. b) In a case, that the temperature is too low, heat water using Bursen burner to obtain

desired one. XII.

Place beaker with water into polystyrene polystyrene cup. This will help to slow the heat loss/ gain from environment. This will make experimental results more ac curate.

XIII.

Put the next test tube into water bath and wait for three minutes. Measure the time with the stopper, to avoid mistakes.

XIV.

After 3 minutes, the homogeneous solution get the temperature of the water bath. Immediately take out the test tube and add 3 drops drops of 3% hydrogen peroxide.

XV.

Wait 5 seconds and using ruler measure the height of produced foam.

XVI.

Record the data and repeat the steps X to XV for the rest 8 test tubes.

XVII.

Repeat the steps from IV to XVI for the next homogeneous solutions at temperature     and  and record outcomes.








Data collection:

Qualitative data:

In samples with low temperature of homogeneous mixture, the height of foam smaller. The tallest foams were obtained from   . However in the solutions with high temperature, e.g.  , the foam was absent, which is the result of denatured denatured protein. This led me to notice trend that with the increase of temperature, the foam height increases, Contrary, in   and   mixtures, we could observe the decrease decreas e in height hei ght of foam produced and no foam respectively.

Quantitative data:








Data processing: Mean:

Mean is the average of outcomes obtained from all trials for one type of solution. It will be very useful in drawing conclusions. Considering the average value for each type of medium, we will be able to see the pattern – the the relationship between the concentration of ethanol and the rate of diffusion. The formula is:

 

         

,

where                    are the respective values of absorbance from one kind of solution.

Table 2.

Mean height in cm of foam produced by the reaction of hydrogen peroxide with homogeneous mixture mixture at different temperatures. Temperature of Mean height homogenous solution of foam ° / C ± 0.1 / cm 100

0.0

40

1.50

30

3.51

20

1.81







Candidate number: ******-006 ANOVA Test:

ANOVA Test is the statistical test used to determine the difference between means of multiple independent groups, which in this experiment are different temperatures of homogeneous solutions. The purpose of this test is to check the validity of null hypothesis, which is :

where µ is the value of group mean and k is is number of groups5. The null hypothesis states that means of all groups are equal and by conducting ANOVA test, the hypothesis can be rejected or confirmed.

Picture 2. Picture represents the results obtained from ANOVA test calculated in Excel.







Candidate number: ******-006 null hypothesis and therefore conclude that there is huge difference between groups.

Uncertainties:

Calculating uncertainties is very important for analyzing experimental data. We have already calculated mean and standard deviation, but what we also need is the uncertainties involving mediums.

1) Total percentage uncertainty

 

 

Table 3.

Total percentage uncertainty of foam produced by the reaction of h ydrogen peroxide with homogeneous mixture mixture at different temperatures. Temperature of Total percentage homogenous solution uncertainty of foam ° / C ± 0.1 / % 100

0.00

40

6.67

30

2.76

20

5.50

10

13.64

2) Absolute uncertainty

 

    

Table 4.

Absolute uncertainty of foam produced by the reaction of hydrogen peroxide










Data presentation: Now, as we collected and processed all data and calculated uncertainties, we can present them together in one table and then translate into graph. graph. Table 5.

Mean height of foam with absolute uncertainty at different temp eratures of homogenous solution Temperature of homogenous solution / °C ± 0.1

Mean height of foam with absolute uncertainty / cm

100

0.00±0.0

40

1.50±0.1

30

3.51±0.1

20

1.81±0.1

10

0.76±0.1

I displayed results on the graph, but I was not able to make a trend line, because in my investigation I did not find optimum temperature and its value.















Conclusion: Having my knowledge and going on background information, I can conclude that the experimental results are reasonable and justifiable. During the experiment I confirmed that my hypothesis was correct, because as we could notice with the increase the enzyme activity expresses as the height of foam, increases with the increase of temperature. At low temperature, enzymes work much slower, because the movement of particles is too slow, they do not catalyze and therefore are not able to speed up the reaction. As temperature increases, the rate of reaction increases to the optimum point, which in my experiment is little above 30°C.

We can see that at     , the height of foam rapidly decrease, slowing down

chemical reactions in Agarius biporus. This shows that the reaction starts to becoming denatured and that this process is much faster than the increasing the enzyme activity. At the end, at 100 °C , the enzyme becomes denatured, the protein changes its shape and are useless (inactive in biological reaction) and stop working. Points plotted on the graph 1, proves that the slope of enzyme activity increases slower with increase the increase of temperature, than decreases after reaching optimum temperature. It means that even a little higher temperature than optimum, makes a significant damage to the enzyme.







Candidate number: ******-006 from water bath before starting the next trials. This might affect, however slightly, but still could change outcomes. Timing 5 second is very difficult, I had to be really focus and despite my most effort to measure the height of foam after exactly 5 second, I am painfully aware that it was unlikely to detect result exactly at the same moment. Using different way of measurement foam height will eliminate eliminate the major errors and give much more more accurate results. What is more, to avoid avoid lose of temperature and evaporation of water, test tubes during heating should be covered and conducting experiment for   when the rate of evaporation is high, water replacement in water bath might be good idea. In my experiment I used different temperatures with 10 °C difference. I concluded that the optimum temperature is little above 30 °C and was not able to give more specific result. Having professional equipment, I would changed the scale with 5 °C difference.








Bibliography: Books: 1. Atkins P., de Paula J., 2006. Physical chemistry for the Life Sciences, UK, Oxford,

Oxford University Press. 2. Greenwood T. , Allan R., 2009. Senior Biology 2, 2 , UK, Edinburgh, Biozone. 3. Roberts M., Reiss M., 2000. Advanced 2000. Advanced Biology, Biology, UK, Cheltenham, Nelson.

Webs:

1. Lard statistics, One-way ANOVA. Available on: https://statistics.laerd.com/statistical-

guides/one-way-anova-statistical-guide.php.. [Access: 09.01.2014] guides/one-way-anova-statistical-guide.php

2. Wikipedia, Agaricus bisporus. Available on:

http://en.wikipedia.org/wiki/Agaricus_bisporus.. [Access: 09.01.2014] http://en.wikipedia.org/wiki/Agaricus_bisporus

IB Biology Lab report

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