Biology IA 2019

What is the effect of increasing concentration of substrate being hydrogen peroxide (1%, 1.5%,
2%, 2.5% and 3%) on enzymatic activity of catalase in dried yeast measured by the amount of
oxygen gas (cm 3) produced when reacted together after 1 minute?
1.0 Introduction
1.1 RESEARCH QUESTION
What is the effect of increasing concentration of substrate being hydrogen peroxide (1%, 1.5%, 2%, 2.5% and 3%) on
enzymatic activity of catalase in dried yeast measured by the amount of oxygen gas (cm3) produced when reacted
together after 1 minute?

1.2 BACKGROUND INFORMATION

1300 enzymes are present in the human body producing 100 000 various chemicals enabling us to hear, feel, see, move,
digest food and think (Enzyme Science , 2019). From the construction of DNA and proteins by stringing together
nucleotides and amino acids to the breakdown of sugar and fat into energy, enzymes carry out numerous chemical
reactions with in our bodies on a daily basis enabling our bodies to function (Biology Dictionary , 2019).

Enzymes are a globular protein that act as a catalyst in biochemical reactions occurring in the body to produce product
essential for daily human life functions. An enzyme’s main function is to work as catalysts by speeding up chemical
reactions by reducing activation energy without being self-involved and convert reactants known as substrates into
products for the body to utilise.

Enzymes are protein macromolecules with a defined three-dimensional structure (Wikiversity , 2019). They consist of a
numerous amount of amino acids linked together by peptide bonds forming a polypeptide (Wikiversity , 2019). Enzymes
catalyse reactants into products through a region on the surface of the enzyme called the active site. The active site
shape permits binding only of a specific molecular substrate that then undergoes catalysis (Merriam-Webster , 2019). The
binding of the substrate to the active site leads to the reaction being catalysed and products formed and released. Figure
1 illustrates below.

Figure 1: An image of enzyme highlighting the active site

on the surface of the protein and binding of a substrate to
the active site resulting in catalysis.

There are two proposed theories explaining how substrates bind to the active site in order to form products referred to as
enzyme-substrate specificity. Specificity is the ability of an enzyme to choose exact substrate from a group of similar
molecules, operating through the structural and chemical complementarity between enzyme and substrate
(easybiologyclass, 2019).

The first theory is known as the lock key hypothesis, outlining that both a substrate and an enzyme have specific
geometric shapes that fit exactly into each other and if the substrate does not align the physical structure of the active site,

1
catalysis will not occur. However, this hypothesis did not explain the stabilization of the enzyme and hence the induced fit
model better illustrates binding and catalysis of enzymes and substrates (Klazema, 2014).

Figure 2: An image illustrating the lock-key hypothesis. Highlighting

that a substrate requires a specific shape that corresponds with the
shape of the active site allowing it to bind and catalyse.

The induced fit model states that a chemical attraction between the substrate and enzyme occur when a substrate
approaches the enzyme, forcing a conformational change in the structure of the active site allowing it to bind and products
to form through catalysis.

Figure 3: An image explaining the conformational change in

shape of active site, through chemical attraction between
substrate and active site leading to

Products are formed when a substrate and active site bind together via collisions. Collisions are the binding of substrates
to active sites of enzymes. Enzymatic activity (rate of reaction of enzymes producing products) is heavily reliant on the
level of collisions occurring, as an increase in the number of collisions will lead to the formation of more products faster
and visa versa. Multiple factors influence the number of collisions that occur, consisting of, temperature, pH level and
substrate concentration. This investigation will specifically be focusing on substrate concentration.

Substrate concentration is the amount of substrate/reactants present in the reaction that have the potential to be turned
into products (Study.com, 2019). The higher the amount of substrate present in the reaction the more chance of collisions
occurring will be present and hence the rate at which the collision occur will increase, increasing reaction rate, as the
probability of collisions will increase sue to more substrates being present. However, optimum concentration of substrates
in a reaction can cause active sites to be occupied and fully working at maximum efficiency. As illustrated in figure 4. The
collisions become constant and do not increase due to no active sites being available for catalysis.

2
 Figure 4: Image illustrating the increase of substrate
concentration in a reaction and its affect on reaction rate.

In this investigation, will focus on the enzyme catalase in the reaction between catalase and hydrogen peroxide. In our
bodies, cells produce the enzyme of catalase to remove hydrogen peroxide from the body as hydrogen peroxide is a by-
product of respiration in any organism exposed to oxygen, is harmful and must be removed as soon as it is produced by
the cell (Nuffield Foundation , 2019). This reaction is as follows,
𝐶𝑎𝑡𝑎𝑙𝑎𝑠𝑒
𝐻𝑦𝑑𝑟𝑜𝑔𝑒𝑛 𝑃𝑒𝑟𝑜𝑥𝑖𝑑𝑒 𝑊𝑎𝑡𝑒𝑟 + 𝑂𝑥𝑦𝑔𝑒𝑛 𝐺𝑎𝑠

2𝐻2 𝑂2 → 𝐻2 𝑂 + 𝑂2

This investigation will investigate the effect of changing the substrate concentration of catalase on the production of
oxygen gas. Dried yeast will be playing the role of catalase and a water displacement method will be used to measure and
collect the oxygen gas produced. The substrate concentration will be investigated through changing the concentration of
hydrogen peroxide in intervals of 0.5%, from 1% up to 3% (1%, 1.5%, 2%, 2.5% and 3%). The equation of this reaction is
as follows,

𝑌𝑒𝑎𝑠𝑡 + 𝐻𝑦𝑑𝑟𝑜𝑔𝑒𝑛 𝑃𝑒𝑟𝑜𝑥𝑖𝑑𝑒 → 𝑊𝑎𝑡𝑒𝑟 + 𝑂𝑥𝑦𝑔𝑒𝑛 𝐺𝑎𝑠

𝐶19 𝐻14 𝑂2 + 𝐻2 𝑂2 → 𝐻2 𝑂 + 𝑂2

1.3 HYPOTHESIS
By increasing the substrate concentration of hydrogen peroxide in the reaction, the rate of reaction and oxygen gas
production will increase as the concentration percentage of hydrogen peroxide increases. This will occur due to, more
substrates in the reaction being present allowing for more margin of collisions to occur as there are more substrates that
can bind and catalyse to the active site of the enzyme. As a result of increased substrates, the reaction rate will also
increase as the active sites will be consecutively binding and producing oxygen gas because more substrates will be
colliding due to the increase in reactant numbers.

1.4 VARIABLES
Independent Variable:
● Hydrogen peroxide concentration (1%, 1.5%, 2%, 2.5% and 3%)

Dependent Variable:
● Oxygen mass (g) (± 5cm3)
3
1.5 CONTROLS
Variables Variables Measured Possible effect on data How the variable will be
changed/ measured/ controlled

Controlled pH level of hydrogen Difference in pH levels across the The pH level of all hydrogen
Variables peroxide hydrogen peroxide concentrations peroxide concentrations used will
used can be different from optimum be ensured to be kept the same.
pH level impacting the
concentration of hydrogen ions
present in the solution and reacting
with the yeast causing structural
changes and potential denaturation
of enzyme leading to a significant
change and inaccuracy in reaction
rate and production of oxygen gas.

Amount of hydrogen Variations in the amount of The hydrogen peroxide volume was
peroxide measured and hydrogen peroxide in the reaction kept the same across all trials of a
used in experiment – will lead to an unfair test as more volume of 20 ml.
20ml volume of hydrogen peroxide will
lead to more solution for the yeast
to react with hence altering the
reaction rate and production of
oxygen gas production.

Amount of yeast used in Variation in the amount of yeast The yeast mass measured present
the reaction – 2g measured in the reaction will lead in the reaction was kept the same
to an unfair test as there will be across all trials of 2 grams.
more enzymes present in the yeast
to react in the reaction leading to
inaccuracy in the reaction rate and
production of oxygen gas.

Time The experiment would result in an 1 minute was dedicated to all trials
unfair test if the time for reaction for which the reaction was
allowed to each trial was different, measured through the water
because some trials would be displacement method.
dedicated more or less time for the
reaction leading to less or more
oxygen gas production making the
results inaccurate.

Uncontrolled Temperature of Data was gathered over 2 days The experiment occurred in a
Variables experimental conditions both in the morning and afternoon enclosed room restoring similar
therefore, the temperature of the temperature conditions therefore,
room the experiment was minimal impact of the reaction rate
conducted under had fluctuations. of the solution.
This could cause the reaction of the
yeast and hydrogen peroxide to
either slow down or speed up
according to the temperature
because excess or not enough
kinetic energy from temperature
was present impacting the solution.

4
1.6 MATERIALS
1. 1x clamp and stand 10. 1x 250ml measuring cylinder (± 5cm 3)
2. 1x electronic balance (±0.01) 11. 1x pipette
3. 1x 100ml hydrogen peroxide (1%) 12. 1x plastic tray
4. 1x 100ml hydrogen peroxide (1.5%) 13. 1x plastic tube
5. 1x 100ml hydrogen peroxide (2%) 14. 1x rubber topper
6. 1x 100ml hydrogen peroxide (2.5%) 15. 1x stopwatch
7. 1x 100ml hydrogen peroxide (3%) 16. 2x 250ml beaker
8. 1x Lowan yeast dried instant 17. 5x 50ml beaker
9. 1x 25ml measuring cylinder (± 0.5cm 3) 18. 5x 250ml conical flask

1.7 PROCEDURE
1. A mortar and pestle were used to grind the yeast until it became a fine powder which was lighter in colour and
less grainy than the original.

2. A balance was used to measure 2 grams of yeast and placed in a 50ml beaker.
3. 20ml of 1% hydrogen peroxide was measured into a 25ml measuring cylinder and poured into a 250ml conical
flask, where the reaction would take place.

4. The plastic tray was half filled with tap water, ready for the water displacement.
5. The 250ml measuring cylinder was filled with water and inverted in over the tray of water, with the open end under
the surface of the water in the tray and with the end of the rubber tubing in the measuring cylinder. Clamp was put
in place to stabilise the structure.

6. Yeast was poured into the 250ml conical flask.

7. Instantly, a rubber bung was placed on top of the opening of the conical flask and immediately started the
stopwatch.

8. After 1 minute, the rubber bung was pulled out from the conical flask and the volume of oxygen was recorded.
9. These steps were repeated for four more times, consisting of five trials for each concentration.
10. Steps 1-9 were completed for hydrogen peroxide concentrations, 1%, 1.5%, 2%, 2.5% and 3%.

Figure 5: Example set up image of the water

displacement method used to execute the practical
experiment.

5
1.8 SAFETY, ETHICAL AND ENVIRONMENTAL CONCERNS
Concerns Potential Hazard Control Measures and Management

Safety

Glassware The use of glassware may lead to Lab coats, safety goggles and leather
breakage leading to potential chance shows must be worn at all times to
of hurts on skin. ensure glass fragments do not come
in direct contact with skin to cause
cuts and injuries. Need to be careful
whilst dealing with glassware during
experiment.

Hydrogen Peroxide Direct contact of solution with skin or Lab coats, leather shoes and safety
body can cause minor to fatal burns glasses must be worn at all times
and/or irritation and breathing difficulty ensuring that the solution does not go
due to its high corrosive properties into eyes or come in contact with skin
and toxic nature. casing irritation and injuries.

Yeast Small yeast particles and unpleasant Lab coats and safety glasses should
fumes from the yeast can cause be worn at all times ensuring that
irritation to those suffering from particles do not come in contact with
asthma and yeast allergies. The small eyes as well as regulation of fresh air
particles can cause irritation in eyes. in the lab whilst performing the
experiment.

Environmental

Waste Management Hydrogen Peroxide is a toxic solution Waste discarded from this experiment
which if disposed freely into the was disposed according to Education
environment via the sink or other Queensland’s disposal methods and
generic disposal methods might safely disposed making sure it was
negatively impact the environment not disposed into the environment
and affect ecosystems by damaging, harming the ecosystems.
disease or toxic poisoning.

Ethical

No ethical concerns were identified in this investigation as no human or animal contents were breached.

6
2.0 Analysis
2.1 QUALITATIVE DATA
● When reacting with the hydrogen peroxide the yeast expands to create bubble type structures with air as
demonstrates figure 6.

Figure 6: Bubble air gaps created after

the reaction of yeast with hydrogen
peroxide.

● After the reaction, the solution had very unpleasant smelling odour.

● The mixture turned into the colour of yeast after mixing, the colour was yellowish biscuit colour with multiple bubbles.

7
 Figure 7: 2.5% of hydrogen peroxide Figure 8: 1% of hydrogen peroxide concentration after reaction.
after reaction. Filling up nearly half the Barely touching a quarter of the way through the conical flask
conical flask with the reaction bubbles with the bubbles formed from the reaction.
formed.

● The height of the bubbles created after the reaction increased as the substrate concentration of hydrogen peroxide
increased, as shown with figures 7 and 8.

● The gas collection in the 250ml measuring cylinder increased in speed as the concentration increased, it was quicker
and faster compared to lower concentrations.

● Minimal precipitate was seen to be formed during the experiment on the sides and on the top surface of the reaction.

8
 Figure 9: A foam layer created on top of
the mixture by the yeast reacting with the
hydrogen peroxide.

● A foam like surface was formed on the top of the reaction creating a cloud of the top of the mixture, as shown in figure
9.

2.2 QUANTITATIVE DATA – RAW DATA

Table 1: Raw data values of oxygen gas production

Concentration Amount of Oxygen Gas Produced (cm3) (± 5cm3)

of Hydrogen
Peroxide Trial 1 Trial 2 Trial 3 Trial 4 Trial 5

1% 68 59 66 63 70

1.5% 96 91 95 95 93

2% 156 152 155 153 151

2.5% 194 177 180 182 184

3% 237 242 241 244 238

9
2.3 QUANTITATIVE DATA – PROCESSED DATA
Table 2: Sample calculation values and examples for mean, standard deviation and t-test.

Calculation Example

Mean Mean for 1% hydrogen peroxide

∑
𝑥 ∑ 𝑥
𝜇= 𝜇=
𝑛 𝑛
𝑆𝑢𝑚 𝑜𝑓 𝑎𝑙𝑙 𝑣𝑎𝑙𝑢𝑒𝑠 68 + 59 + 66 + 63 + 70
𝑀𝑒𝑎𝑛 = =
𝑁𝑢𝑚𝑏𝑒𝑟 𝑜𝑓 𝑣𝑎𝑙𝑢𝑒𝑠 5
𝜇 = 65.2𝑐𝑚3
Standard Deviation Standard deviation for 1% hydrogen peroxide

∑ (𝑥 − 𝜇)2 ∑ (𝑥 − 𝜇)2
𝜎= √ 𝜎= √
𝑛 𝑛
Where,
∑ ((68 + 59 + 66 + 63 + 70) − 65.2)2
𝜎= √
𝜎 = 𝑆𝑡𝑎𝑛𝑑𝑎𝑟𝑑 𝑑𝑒𝑣𝑖𝑎𝑡𝑖𝑜𝑛 4
𝜎 = 4.32
∑ = 𝑆𝑢𝑚 𝑜𝑓

𝑥 = 𝐸𝑎𝑐ℎ 𝑣𝑎𝑙𝑢𝑒 𝑖𝑛 𝑡ℎ𝑒 𝑑𝑎𝑡𝑎 𝑠𝑒𝑡

𝜇 = 𝑀𝑒𝑎𝑛 𝑜𝑓 𝑎𝑙𝑙 𝑣𝑎𝑙𝑢𝑒𝑠
𝑛
= 𝑁𝑢𝑚𝑏𝑒𝑟 𝑜𝑓 𝑣𝑎𝑙𝑢𝑒𝑠 𝑖𝑛 𝑡ℎ𝑒 𝑑𝑎𝑡𝑎 𝑠𝑒𝑡
T-Test T-Test for 1% hydrogen peroxide compared to 3% hydrogen peroxide

T-Test is conducted by Excel.

The two columns are aligned side

by side and a t-test that is 2-tailed,
unpaired and unequal variance is
created.

The array 1 and 2 refer to the two

column data sets and tails has a
value of 2 because it is a two tailed
t-test. Type has a value of 3
because the number 3 suggests an
unequal variance t-test.

10
Table 3: Table of processed data values consisting of mean and standard deviation for all concentrations of hydrogen
peroxide.

Concentration Mean (cm3) (± 5cm3) Standard Deviation

1% 65.20 4.32

1.5% 94.00 2.00

2% 153.40 2.07

2.5% 183.40 6.47

3% 240.40 2.88

Table 4: Table illustrating T-Test calculations and values.

11
2.4 GRAPHS
250
240
230
220
210
Oxygen Gas Produced (cm3) (±5cm3)

200
190
180
170
160 y = 87.96x - 28.64
150 R² = 0.9874
140
130
120
110
100
90
80
70
60
50
40
30
20
10
0
0 0.5 1 1.5 2 2.5 3 3.5
Hydrogen Peroxide Concentration %

Graph 1: Mean values of oxygen gas produced correlated with hydrogen peroxide concentration values, with depicted
linear trendline, r-squared value, equation of line-of-best-fit and error bars of 1 positive and 1 negative error margin.

2.5 ANALYSIS
Graph 1 depicts the correlation between the measured oxygen gas production form the reaction and increasing substrate
concentration of hydrogen peroxide. The individual data points depict a linear correlation as all points illustrate that as the
concentration of hydrogen peroxide increases the amount of oxygen gas produced increases to. Which is further
supported by the linear trendline, providing a clear view of the linear trend amongst the data. The linear trend can be
further supported by the analysis of the r-squared value which is 0.9874, meaning that the data highly corresponds with
each other, confirming the strong positive linear correlation.

From the graph it can be determined that the effect of increasing the concentration of hydrogen peroxide has led to an
increase in enzymatic activity of catalase present in the yeast indicating implying that the production of oxygen gas ha
increase, which can be seen through the graph.

The standard deviation error bars on the graph depict that minimum error has occurred because the error bars are very
small in length and suggesting that the data is accurate and précised.

The positive gradient of the linear trendline also depicts that the rate of reaction was strong and fast and increased as the
concentration of hydrogen peroxide increased.

Table 4 regarding the t-test has derived two hypotheses, consisting of a null hypothesis and an alternate hypothesis.

The null hypothesis states that, there is no significant difference between 1% hydrogen peroxide concentration and 3%
hydrogen peroxide concentration. Whereas the alternate hypothesis states that, there is a significant difference between
the 1% hydrogen peroxide concentration and 3% hydrogen peroxide concentration.

The mean value for oxygen mass production in 1% concentration was 65.2 ml and mean value for 3% hydrogen peroxide
concentration was 240.4ml. The standard deviation was 4.32 and 2.88, indicating the large spread of data. The difference
12
between the two data values was significantly different as the t-test value was above 0.05, indicating that there was a
significant difference. Implying that the increase in substrate concentration harshly impacted the production of oxygen
gas.

3.0 Evaluation

3.1 DISCUSSION
The results suggest an increase in oxygen gas production as the substrate concentration of hydrogen peroxide increases.
This is due to the number of substrates present in the reaction that then stems on to the amount of collisions occurring
resulting in products forming which is the oxygen gas. As the concentration of hydrogen peroxide increased there were
more substrates present in the reaction to collide with the active site and produce oxygen gas, hence the oxygen gas
production increased as the hydrogen peroxide concentration increased. The rate of reaction of enzymatic activity also
increased because there were more substrates present which signified a greater population of reactants and hence the
collisions kept on occurring making the reaction rate increase.

This is supported by Sam Adam Day, stating that, “Increasing Substrate Concentration increases the rate of reaction. This
is because more substrate molecules will be colliding with enzyme molecules, so more product will be formed.” (Day,
2019)

As a result, more production formation was clearly evident in the results gathered and hence it can be concluded that the
rate of reaction had increased as the concentration increased and more collisions in the reaction were occurring due to
more presence of substrates.

However, the continuous inclining trend on the graph suggested that the active site of enzymes was not yet working at
optimum caliber because there was no declining of gradient suggesting that the active sites were occupied and too much
substrate was present in the reaction.

The investigation that was conducted included many weaknesses and strengths. The strengths of the investigation
consisted of repeating five trials for each concentration enabling us to gather accurate and precise results leading to the
minimization of random error present in the trials and confirming the validity of the results. All trials were performed for 1
minute providing sufficient time for the reaction to occur and all the possible produced oxygen gas to be collected so
accurate a precise results are gathered. A strength of the experiment was that it was reliable as all the controlled variables
were controlled very well providing a very niche margin for errors that could impact accuracy and precision of results.

Very few weaknesses stemmed from this investigation, especially considering the results gathered. However, some
weaknesses identified in the experiment were,

13
 Source of Error Impact on Results Improvements

Systematic Error

After each trial of each experiment the This could have lead to the hydrogen This can be avoided by using a fresh
conical flask the reaction was taking peroxide and yeast reacting with conical flask for each trial. Therefore,
place in had to be rinsed and water at the same time s each other, the conical flask in the previous trial
therefore left a residue of water. As a leading to inconsistencies in the will not be used allowing no water to
result, for each concentration of trials results. This could have also lead to be present in the reaction.
one and two the reaction also the hydrogen peroxide reacting with
consisted of water. the after first because it was placed in Or the flask could be rinsed, and
the flask before the yeast, potentially residue wiped down well before the
This occurred due to the limitation in contaminating the experiment. use on the next trial however this
equipment offered as each group was method cannot guarantee accuracy.
only offered one conical flask to
conduct all five trials.

Random Error

Measuring the hydrogen peroxide into The volume hydrogen peroxide in the Use equipment that has low values of
the conical flask may have caused reaction could have differed from trial uncertainty in order to reduce error.
errors due to inaccurate measuring to trial causing inaccuracies and un Use a pipette to measure out exact
because of meniscus, etc. precise data and casing more or less values of volume.
oxygen gas to be produced.

Occasionally, whilst measuring the Therefore, in some trials the yeast Ensure the scales do not flicker, and if
yeast the electronic scales would may be below or above the 2g mass that is occurring use a non-flickering
flicker. level, which had a impact on the scales to achieve accuracy in
amount of oxygen gas produced, measurement.
impacting the accuracy of the
experiment.

3.2 CONCLUSION
This experiment was investigating the effect of increasing substrate concentration of hydrogen peroxide (1%, 1.5%, 2%,
2.5% and 3%) in the reaction with dried yeast, providing the enzyme of catalase, observed through measuring the amount
of oxygen gas produced by using a water displacement method.

It was predicted that by increasing the substrate concentration of hydrogen peroxide in the reaction, the rate of reaction
and oxygen gas production will increase as the concentration percentage of hydrogen peroxide increases. This will occur
due to, more substrates in the reaction being present allowing for more margin of collisions to occur as there are more
substrates that can bind and catalyse to the active site of the enzyme. As a result of increased substrates, the reaction
rate will also increase as the active sites will be consecutively binding and producing oxygen gas because more
substrates will be colliding due to the increase in reactant numbers.

The processed data gathered, and trend observed have supported my hypothesis as trends can be easily identified by the
data that oxygen gas production increases when hydrogen peroxide concentration increases. This can be further
enhanced by the quantitative and qualitative data as both forms of data support the hypothesis.

This investigation has concluded that by increasing substrate concentration the enzymatic activity of a reaction increases
as more oxygen gas was produced as concentration increased because more substrate particles were present in the
solution which allowed for a great margin of collisions to occur leading to more product formation hence explaining the
increase in oxygen gas production when hydrogen peroxide concentration increased.

14
An extension that could be provided to this investigation would be to investigate the effects of pharmaceutical drags on
enzymatic activity. This could be investigated by adding in a pharmaceutical drug such as Panadol with the yeast to
compare and contrast the oxygen gas being produced. To further enhance the investigation a t-test could be conducted to
identify if a significant difference was made by the addition of a pharmaceutical drugs on the production of oxygen gas
and if the drugs impacted the enzymatic activity, positive or negatively. A research question that could be developed for
this investigation could be, the effect of pharmaceutical drugs (Panadol) on enzymatic activity of hydrogen peroxide and
dried yeast reaction measured by the amount of oxygen gas produced. If this investigation is successful in the illustration
of the effect of pharmaceutical drugs on enzyme activity, then it would prove to be highly useful and convenient in cancer
research and further cell studies.

In order to further enhance this format of investigation, enzymatic activity on different blood glucose level concentrations
could be tested. In order to provide an insight as to how different levels of sugar present in the blood impact the body’s
ability to decompose hydrogen peroxide. Sugar has been claimed to be "sweet poison" and in some new leading
research, sugar has been claimed to be a substance that encourages cancer cell growth, hence in this investigation
different sugar levels could be tested identifying how different sugar levels may impact normal cell function, potentially
assisting in cancer and diabetic research. This could be investigated by mixing yeast and different volumes for sugar
together or using potatoes instead of yeast as the characteristics of potatoes are more human like. Glucose could be
injected into the potatoes and using the water displacement method, reacted with hydrogen peroxide and oxygen gas
production measured. A research question to this investigation would be, what is the effect of different concentrations of
glucose in potatoes on the oxygen gas production when reacted with hydrogen peroxide?

REFERENCES
Biology Dictionary . (2019). Active Site . Retrieved from Biology Dictionary : https://biologydictionary.net/active-site/

Day, S. A. (2019). Factors Affecting Enzymatic Activity . Retrieved from A-Level Notes :
https://alevelnotes.com/notes/biology/biological-molecules/enzymes/factors-affecting-enzyme-activity

easybiologyclass. (2019). Biochemistry of Enyme Substrate Specificity and its Classification with Examples . Retrieved
from Easy Biology Class: https://www.easybiologyclass.com/enzyme-substrate-specificity-types-classification/

Enzyme Science . (2019). Enzyme FAQ. Retrieved from Enzyme Science Exceptional Enzyme Formulas :
https://enzyscience.com/pages/enzyme-faq

HuffPost Living . (2012, July 19). Why Does My Face Flush When I Exercise? Retrieved from Everyday Health :
https://www.everydayhealth.com/fitness/why-does-my-face-flush-when-i-exercise.aspx

Khan Academy . (2018). Steps of Cellular Respiration . Retrieved from Khan Academy :
https://www.khanacademy.org/science/biology/cellular-respiration-and-fermentation/overview-of-cellular-
respiration-steps/a/steps-of-cellular-respiration

Klazema, A. (2014, June 18). Lock and Key Hypothesis: Understanding Enzymes. Retrieved from Udemy, Inc.:
https://blog.udemy.com/lock-and-key-hypothesis/

Merriam-Webster . (2019). Active Site . Retrieved from Merriam-Webster : https://www.merriam-

webster.com/dictionary/active%20site

Nuffield Foundation . (2019). Investigating an enzyme-controlled reaction: catalyse and hydrogen peroxide
concentration. . Retrieved from Nuffield Foundation : https://www.nuffieldfoundation.org/practical-
biology/investigating-enzyme-controlled-reaction-catalase-and-hydrogen-peroxide-concentrat

Solan, J. (2017, September 11). Why Does Our Heart Rate Increase During Exercise? Retrieved from LiveStrong.com:
https://www.livestrong.com/article/321955-my-heart-rate-rises-with-light-activity/

15
Study.com. (2019). Substrate Concentration: Definition and Effect on Enzyme Activity. Retrieved from Study.com:
https://study.com/academy/lesson/substrate-concentration-definition-effect-on-enzyme-activity.html

Wikiversity . (2019, April 29). Enzyme structure and function. Retrieved from Wikiversity :
https://en.wikiversity.org/wiki/Enzyme_structure_and_function

16