Investigation: Enzyme and Substrate Concentrations - Biology

Investigation: Enzyme and Substrate Concentrations - Biology

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How Does Concentration Affect the Reaction Rates of Enzymes?


  • to observe enzymatic reactions and quantify and products created in those reactions

  • to determine the effect of substrate and enzyme concentration rates of reaction

Background information:

Hydrogen peroxide (H2O2) is a common but poisonous by-product of cellular metabolism, but H2O2 does not accumulate in cells because it is decomposed into water and oxygen gas. The decomposition of the hydrogen peroxide is facilitated by catalase, an enzyme present in most cells.

The reaction is: 2H2O2→ 2H2O + O2

One molecule of catalase can catalyze the decomposition of approximately 4 x 107 molecules H2O2 per second! Catalase is stored in special vesicles of the cell called peroxisomes.

In this lab activity, you will be using yeast catalase to observe how increasing and decreasing the concentration of the enzyme and substrate can affect the reaction rate.


  • Hydrogen Peroxide 3%
  • 4 beakers or cups for H2O2 dilutions
  • 5 small cups for yeast dilutions
  • Graduated cylinders
  • Filter paper and hole punch
  • Forceps
  • Stopwatch or timer
  • Active dry yeast

Create your stock catalase solution

1. Dissolve 1 tsp (2-4 grams) of yeast in 200 ml of warm water.
*This solution may already be made for you.

2. Mix well and let sit for about 3 minutes

3. Stir gently to keep solution and yeast mixed.

Observation of Catalase Activity

1. Pour 80 ml of H2O2 into a small beaker.

2. Cut a filter paper disk using a hole punch

3. Use forceps to soak a the punched disk in your stock catalase

4. Place the disk into a beaker with H2O2. Observe what happens to the disks when dropped into peroxide. If nothing happens you may need to troubleshoot your experiment. Try stirring your catalase solution or dipping the disk in the H2O2 to break the surface tension. If you are still not seeing anything happen, consult your instructor.

5. Perform this procedure again and record the time it takes for the disk to drop and then raise to the surface. Perform multiple trials to perfect your technique. Convert all readings to seconds to take an average. Place your data in the first column of the data table.

Effect of Substrate Concentration

The H2O2 started at 3%. You will now dilute the peroxide in order to change its concentration.

1. Place 40 ml of H2O2 into a new beaker. Add 40 ml of water. H2O2 concentration = 1.5%

2. Place 20 ml of H2O2 into a new beaker. Add 60 ml of water. H2O2 concentration = .75%

3. Place 10 ml of H2O2 into a new beaker. Add 70 ml of water. H2O2 concentration = .375%

4. Perform the floating disk procedure for each concentration. You can do multiple trials at the same time.


3% H2O2

1.5% H2O2

0.75% H2O2

0.375% H2O2

Trial 1

Trial 2

Trial 3


5. Create a graph that compares the averages for each concentration. (Be sure to label your axes.)

6. Based on your data, how does the concentration of the substrate affect the enzyme reaction rate? Suggest a REASON for these results.

Effect of Enzyme Concentration

Your stock solution of catalase is your 100% solution. Create diluted solutions according to the ratios below and place each in small cups. These cups will be used to dip your filter paper disks.

  1. 100% = 20 ml of catalase + 0 ml of water
  2. 80 % = 16 ml of catalase + 4 ml of water
  3. 60% = 12 ml of catalase + 8 ml of water
  4. 40% = 8 ml of catalase + 12 ml of water
  5. 20% = 4 ml of catalase + 16 ml of water

1. Perform the floating disk procedure for each concentration.


100% catalase

80% catalase

60% catalase

40% catalase

20% catalase

Trial 1

Trial 2

Trial 3


2. Use your data to make a CLAIM that answers the question: How does the concentration of the enzyme affect the reaction rate.

3. Provide EVIDENCE for this claim by briefly summarizing your data or observations.

4. Suggest a REASON for your claim. This is where you consider what scientists understand about enzymes and how enzymes and substrates interact with each other. Your reasoning can include sketches.


10. A competitive inhibitor attaches to the active sites of enzymes. Discuss how inhibitors would change the rate of the reaction rate of catalase. Create a model (drawing) to support your claim.

11. Sketch an experimental set-up that you could use to test the effects of temperature on reaction rates. Annotate your drawing with descriptions so that a reader can clearly understand your design. Consider your variables and what you will be measuring.

12. The beginning of this lab lists two objectives. Summarize what you have learned in this lab to accomplish those two objectives.

Teacher notes:

To save time, I make catalase solution about 20 minutes before the lab, this also gives the yeast time to become active. Beakers work best for the hydrogen peroxide because you can see the disks on the bottom (clear plastic cups can substitute). Dixie cups or medicine cups work for peroxide dilutions.

Students observe that not all their tests are the same. I usually discuss why biological experiments are messy and inconsistent. Some note that the color of the yeast solution varies from top to bottom and that it might matter how far you dip your disks in and how long you keep them there.

The Effect of Substrate Concentration on Enzyme Activity

What is the consequence of increasing the substrate concentration, as measured by thining the concentration of 3 % H peroxide in an aqueous solution ( 0.6 % , 1.2 % , 1.8 % 2.4 % and 3.0 % ) , on the rate of enzyme activity of the enzyme catalase, obtained fromBos primigenius[ 1 ] ( bovine ) liver, measured by utilizing a stop watch ( ± 1 sec ) to obtain the clip it takes for the decomposition of H peroxide to force the filter paper phonograph record to the surface of the H peroxide solution?

If the concentration of H peroxide is increased, so the rate of enzyme activity will besides increase until a certain point, so go changeless.

This is because as the substrate concentration is increased, there are more possibilities for the substrate and enzyme to clash and adhere, doing an addition in the activity of the enzymes [ 2 ] and hence increasing the rate of the decomposition of H peroxide ( making more O and H2O at a quicker gait, which would force the filter paper to the top of the H peroxide solution faster, diminishing the clip observed ) .

However, since the enzyme concentration is unchanged, the substrate concentration can be increased to a point where all active sites of the present enzymes are already occupied with substrates, ensuing in impregnation of the enzymes, such that increasing the substrate concentration will no longer increase the enzyme activity.

Theindependent variableis the per centum concentration of the 3 % H peroxide in the aqueous solution. This will be measured by thining the H peroxide utilizing a graduated cylinder ( ±0.5mL ) . The five per centums will be 0.6 % , 1.2 % , 1.8 % , 2.4 % and 3.0 % . Refer to Postpone 1 for the concluding composing of the 5 conditions.

Table 1.The sum composing, in milliliter, of 3 % H peroxide and distilled H2O to make the concluding per centums for the five chosen conditions.

peroxide in aqueous solution ( % )

New per centum of H peroxide ( now that is has been diluted with H2O ) ( % )

Volume of H Peroxide ( ±0.5mL )

Volume of distilled H2O ( ±0.5mL )

Thedependant variableis the clip it takes for the O bubbles to force the filter paper phonograph record to the surface of the H peroxide solution. This will be measured by utilizing a stop watch ( ±1 second ) and so recorded.

Thecontrolled variablesfor this probe will include:

i??The temperature of the solution and the changeless milieus. This will be monitored by remaining in the same room for the continuance of the experiment and measurement and entering the temperature of the solution before every test. This is done because increasing the temperature of the solution ( or of the milieus ) causes an addition in the kinetic energy of the atoms, and hence increases the possibility of enzyme-substrate complex’s forming. Higher temperatures accordingly increase enzyme activity to a certain point, or until the optimal temperature is surpassed [ 3 ] commanding the temperature therefore minimizes the opportunity of obtaining skewed consequences. The optimal temperature of catalase in a cow is 37, intending that temperatures above37will get down to denature the enzymes, so supervising the temperature will corroborate that it has non been exceeded.

i??The pH and concentration of H peroxide. This will be done by utilizing the same H peroxide solution for every test of each status ( will be taken from the same bottle, 3 % H peroxide ) and mensurating the pH before every test utilizing a pH metre. No extra acids or bases will be added. This will be controlled because enzyme activity is decreased if the pH is increased or decreased from the optimal pH degree of the enzyme, hence doing denaturation and diminishing enzyme activity 3 . It is of import to observe that altering the concentrations of the H peroxide will change the pH somewhat, but non plenty to dispute the truth of the experiment. In add-on, different initial concentrations of H peroxide will take to different diluted concentrations (different conditions ) , so maintaining it changeless, at 3 % , is necessary.

i??The enzyme concentration. The enzyme catalase will be obtained from intermixing bovine liver and H2O. 15 g of bovine liver will be used to make the enzyme rich mixture, and will be used for each test. This is done because increasing the sum of enzymes for different conditions will accordingly increase the figure of active sites that the substrates can adhere to 3 , therefore increasing enzyme activity until the enzyme concentration surpasses the substrate concentration, where the enzyme activity will level out.

i??The volume of the combined solution. Each concluding solution will incorporate a different sum of H peroxide and distilled H2O ( based on which status is being performed and hence what per centum of H peroxide must be used ) . However, the combined volume of each status will be 20.0 ±0.5mL. This is done so that the filter paper phonograph record will go the same distance every clip ( from the underside to the top of the solution ) .

i??The trial tubings used will be the same size ( medium sized trial tubing ) . This is done to maintain the distance that the filter paper phonograph record must go consistent for each test. Increasing the size of the trial tubing will alter its dimensions. More significantly, it will increase the diameter of the trial tubing, thereby diminishing the distance the paper phonograph record must go to make the top of the solution ( because volumes of the solution are to be kept changeless ) which would later diminish the times obtained.

i??The filter paper phonograph record. The dimensions of the filter paper discs must be the same for every test. This will be done by utilizing the same filter paper to cut the phonograph record ( to maintain thickness invariable ) , and each disc will hold a diameter of 6mm, which will be ensured by utilizing a hole cowboy to cut the discs ( doing them perfect circles each clip ) .

i??The pureness of H2O. The H2O obtained will be from a packaged distilled H2O bottle, and will be used for the continuance of this experiment. This is done because different H2O beginnings may incorporate different mineral concentrations [ 5 ] , hence could take to error in the information collected.

i?°300.0 milliliter of 3 % H peroxide solution

i?°220.0 milliliter of distilled H2O

i?°25.0 milliliter graduated cylinders ( ± 0.5 milliliter ) ( x2 )

i?°Mercury thermometer ( ± 1°C )

i?°Medium trial tubings ( x5 )

i?°10cm x 10cm filter paper

i?°Hole cowboy ( 6mm diameter )

i?°Rubber trial tubing stoppers ( x5 )

Safety Precautions:Sodium hydrated oxide is a caustic substance, and can therefore lead to clamber annoyance and do hurt to the eyes [ 6 ] . Wear safety goggles for the continuance of this lab, or until the process has been completed ( solution has been disposed of and equipment has been washed ) . Afterwards, rinse your custodies with soap and H2O. If sodium hydrated oxide comes in contact with tegument, wash with soap and H2O instantly.

1.Find a level tabular array with equal infinite ( around 1m x 1m ) to execute five conditions, each with five tests, and remain at that place for the continuance of the experiment.

2.Gather all needed stuffs ( mention to list of stuffs above ) and make an observation tabular array. This tabular array should include adequate infinite for the measurings of the per centum concentration of H peroxide ( % ) , clip observed for the paper filter phonograph record to make the surface of the solution ( ± 1 sec ) , temperature of the solution before the reaction ( ±1°C ) , pH of the solution before every test ( ± 0.5 pH ) and qualitative observations to be recorded for five conditions each with five tests. Give your tabular array a rubric.

3.Take the 15 g of bovine liver and set into the electric liquidizer. Taking a 25.0 milliliter graduated cylinder, step 20.0 ±0.5mL ofdistilledH2O and pour into the liquidizer. Blend until the substance is wholly assorted together ( approximately 40 seconds ) . If there are any seeable balls of liver, intermix once more for20 seconds, oruntil the consistence is smooth. Pour the mixture into the 50 milliliter beaker. The same enzyme mixture will be used for the continuance of the lab.

4.Take the five medium trial tubings and put them gently onto the trial tubing rack. They will be used throughout the lab.

5.Grab the bottle of 3 % H peroxide solution and maintain it for the continuance of this lab. Make non add any substances to this solution or alter it in any manner. Taking the fresh 25.0 milliliter graduated cylinder, step out 4.0 ±0.5mL of H peroxide. Pour into a trial tubing.

6.Take the 25.0 milliliter graduated cylinder that was used in measure 3, and step 16.0 ±0.5mL of the samedistilledH2O ( use the same H2O beginning for each test ) . Pour the H2O into the trial tubing that already holds the H peroxide. This completed solution now contains 0.6 % H peroxide ( mention to Table 1 ) and should be 20.0 ±0.5mL. Using the quicksilver thermometer, step and record the temperature of the solution ( ±1°C ) . Then step and record the pH of the solution utilizing the pH metre ( ±0.5 pH ) .

7.Repeat stairss 5-6 for the staying four medium trial tubings that were placed onto the trial tubing rack.

8.Take the 10 centimeter x 10 cm filter paper and, utilizing the whole cowboy, cut out a filter paper phonograph record that is 6mm in diameter. Take the filter paper phonograph record and coat it to the full in the enzyme rich liquid that was prepared in measure 3. Chuck the filter paper phonograph record to take any extra liquid, and topographic point it on the terminal of a gum elastic stopper it will lodge to the stopper because it is wet.

9.Take one trial tubing from the trial tubing rack, splash with a splash stick foremost to avoid the subsiding of the H peroxide solution, so infix the stopper steadfastly.

10.Simultaneously invert the trial tubing and get down mensurating the clip it takes for the paper phonograph record to make the top of the H peroxide solution in the trial tubing utilizing the stop watch ( ± 1 sec ) . Once it is at the surface of the solution, halt the stop watch. Record the clip shown and reset the stop watch.

11.Repeat stairss 8-10 with the staying 4 trial tubings in order to hold a sum of 5 tests for this status.

12.Take the 5 medium trial tubing, 5 trial tubing stoppers and two 25.0 milliliters graduated cylinders and rinse them exhaustively with soap and H2O. Once clean, glib dry with paper towels so that the stuffs can be reused for the following status.

13.Repeat stairss 4-12, but replace the per centum of H peroxide with a new status until all five conditions have been performed ( 0.6 % , 1.2 % , 1.8 % , 2.4 % and 3.0 % ) . Mention to Postpone 1 for the right volumes of 3 % H peroxide and distilled H2O needed for each status.

14.When finished, dispose of all solutions by blushing them down the drain with H2O and return all equipment to their original locations.


This is an experiment to examine how the concentration of the substrate hydrogen peroxide affects the rate of reaction of the enzyme catalase.


This is an A-level biology project. It helped me get an A grade for biology many years ago. The whole project is reproduced here for your reference.

Enzymes such as Catalase are protein molecules which are found in living cells. They are used to speed up specific reactions in the cells. They are all very specific as each enzyme just performs one particular reaction.

Catalase is an enzyme found in food such as potato and liver. It is used for removing Hydrogen Peroxide from the cells. Hydrogen Peroxide is the poisonous by-product of metabolism. Catalase speeds up the decomposition of Hydrogen Peroxide into water and oxygen as shown in the equations below.


It is able to speed up the decomposition of Hydrogen Peroxide because the shape of it's active site matches the shape of the Hydrogen Peroxide molecule. This type of reaction where a molecule is broken down into smaller pieces is called an anabolic reaction.

  1. Gas Syringe
  2. Metal Stand
  3. Yeast Catalase
  4. Hydrogen Peroxide
  5. Test Tubes
  6. Beakers
  7. Test Tube Rack
  8. Stop Watch
  9. Pipette
  10. Pipette Filler
  11. Tap Water

To test out how the concentration of hydrogen peroxide affects the rate of reaction first set up the apparatus below.

[Aparatus picture not reproduced]

1. Add 2cm3 of yeast to one test tube. Add 4cm3 of hydrogen peroxide solution at a concentration of 20% to the other test tube. Use a pipette to measure out the volumes. It is very important to accurately measure the amounts of Hydrogen Peroxide, Yeast and water to ensure a fair test.

2. Pour the hydrogen peroxide solution into the test tube containing the yeast and immediately put the gas syringe bung on the end of the test tube, at the same time start the stopwatch.

3. Bubbles should start to rise up the tube and the gas syringe will move outwards, as soon as the gas syringe passes the 30cm3 mark stop the stopwatch and note the elapsed time down to the nearest 1/10th of a second.

4. Repeat the experiment with hydrogen peroxide concentrations of 16%, 12%, 10%, 8%, 4% and 0%. The 0% concentration of hydrogen peroxide solution is done as a control solution to show that at 0% concentration no reaction occurs. The different concentrations of Hydrogen Peroxide are made by adding tap water to the 20% Hydrogen Peroxide in the correct amounts. The table below shows what amounts of Hydrogen Peroxide and water are needed to make the solutions.

Concentration Of Hydrogen Peroxide

Volume Of Hydrogen Peroxide (cm3)

20% 4 0 16% 3.2 0.8 12% 2.4 1.6 10% 2 2 8% 1.6 2.4 4% 0.8 3.2 0% 0 4

5. Repeat all the tests at least three times so that an average can be obtained. Repeating the experiments several times will help to produce better and more accurate results as any inaccuracies in one experiment should be compensated for by the other experiments. Note all the results in a table such as the one below.

Hydrogen Peroxide Concentration 0% 4% 8% 10% 12% 16% 20%
Time Taken (Test 1)
Time Taken (Test 2)
Time Taken (Test 3)
Average of the Tests

The rate can then be worked out by

This gives the rate in cm3 of oxygen produced per second, this is because I am timing how long it takes to produce 30cm3 of oxygen. From these results a graph can be plotted with concentration on the x-axis and time taken on the y-axis.

I am using yeast catalase as opposed to catalase from apples, potatoes or liver because it is easier to get the desired amount of yeast catalase by simply measuring it off. To obtain catalase from a substance such as potato would involve crushing it and with that method you would never be sure of the concentration of the catalase. If the catalase was used up then another potato would have to be crushed and this could produce catalase of a totally different concentration which would lead to inaccuracies in the experiment making this an unfair test.

To ensure this is a fair test all the variables except for the concentration of Hydrogen Peroxide must be kept the same for all the experiments. Variables that must not be altered include:-

Temperature, yeast concentration, type of yeast, batch of yeast, volume of yeast, volume of hydrogen peroxide, air pressure and humidity.

When measuring the volumes of Hydrogen Peroxide, Yeast and Water the measurement should be taken by looking at the scale at an angle of 90 degrees to it to avoid any parallax error.

I predict that as the substrate concentration increases, the rate of reaction will go up at a directly proportional rate until the solution becomes saturated with the substrate hydrogen peroxide. When this saturation point is reached, then adding extra substrate will make no difference.

The rate steadily increases when more substrate is added because more of the active sites of the enzyme are being used which results in more reactions so the required amount of oxygen is made more quickly. Once the amount of substrate molecules added exceeds the number of active sites available then the rate of reaction will no longer go up. This is because the maximum number of reactions are being done at once so any extra substrate molecules have to wait until some of the active sites become available.

I carried out the above experiment and these results were obtained.

Hydrogen Peroxide Concentration 0% 4% 8% 10% 12% 16% 20%
Time Taken (Test 1) 47.3 18.4 17.3 14.5 10.6 9.7
Time Taken (Test 2) 43.3 19 16.7 14.9 11.2 10
Time Taken (Test 3) 52.2 17.2 18.5 11.2 8.6 7.8
Average of the Tests 47.6 18.2 17.5 13.5 10.1 9.2
Rate =30/Average (Cm3/second) 0 0.63 1.65 1.71 2.22 2.97 3.26

All the times are in seconds. The average results are all written down to one decimal place because although the stopwatch gives results to two decimal places it is impossible to get accurate times to two decimal places due to the fact that our reaction times are not fast enough to stop the stopwatch precisely. I then worked out the rates of the reactions with the equation

From these rates I was able to plot a graph of the rate of reaction against concentration of Hydrogen Peroxide.

When the concentration of Hydrogen Peroxide is increased, the rate of reaction increases at a directly proportional rate until the concentration of Hydrogen Peroxide reaches about 16%. If you double the concentration of Hydrogen Peroxide then the rate of reaction doubles as well. When the concentration is doubled from 8-16% the rate goes up from 1.65-2.97 Cm3 Oxygen produced per second, which is an increase of 1.8 times. I would expect the rate to increase two times if the Hydrogen Peroxide concentration is increased two times because there are twice as many substrate molecules which can join onto the enzymes active sites. The reason that the number is less than two times could be put down to the fact that at 16% the Enzyme's active sites may already be close to being saturated with Hydrogen Peroxide. There may also be some experimental error which causes the inaccuracies.

After 16% the increase in the rate of reaction slows down. This is shown by the gradient of the graph going down. At this point virtually all the active sites are occupied so the active sites are said to be saturated with Hydrogen Peroxide. Increasing the Hydrogen Peroxide Concentration after the point of saturation has been reached will not cause the rate of reaction to go up any more. All the active sites are being used so any extra Hydrogen Peroxide molecules will have to wait until an active site becomes available.

The theoretical maximum rate of reaction is when all the sites are being used but in reality this theoretical maximum is never reached due to the fact that not all the active sites are being used all the time. The substrate molecules need time to join onto the enzyme and to leave it so the maximum rate achieved is always slightly below the theoretical maximum. The time taken to fit into and leave the active site is the limiting factor in the rate of reaction.

The diagram below shows what happens.

To help make this experiment more accurate, I repeated it three times and then used the average of all the results to plot a graph with a line of best fit. I tried to keep all the variables except for the concentration of Hydrogen Peroxide the same for all the experiments. However, in reality it is impossible to keep all the variables precisely the same. For example:

a) There is a slight delay between pouring the Hydrogen Peroxide into the yeast, putting the bung on and starting the stopwatch. This will slightly affect all the results but as I carried out all the three steps in the same way for all the experiments it should not make any difference to the overall result.

b) It is also impossible to precisely measure out the amounts of Hydrogen Peroxide, Yeast and Water each time. As the scale on the pipettes shows the volume to the nearest mm3 the volume of the solutions that I used should be correct to the nearest mm3. The volume of gas in the test tube to start with is slightly affected by the amount which the bung is pushed down each time, if the bung is pushed down further then the volume in the tube will be less so the 30cm3 of gas is reached faster.

c) Due to the fairly slow speed of our reactions it is only possible to measure the time of the reaction to the nearest 0.1 second even though the stopwatch shows the measurements to the nearest 0.01 second.

The plotted results on the graph produce a straight line of best fit to begin with which then goes into a curve of steadily decreasing gradient. The only anomalies are the results at 8% and 10%. The result at 8% is slightly above the line of best fit and the 10% result is slightly below it. This is probably due to an experimental error involving one of the factors mentioned above.

This experiment could be improved in a number of ways. It could be repeated more times to help get rid of any anomalies. A better overall result would be obtained by repeating the experiment more times because any errors in one experiment should be compensated for by the other experiments.

Using more concentrations of Hydrogen Peroxide would have produced a better looking graph and I would have liked to use concentrations higher than 20% to extend the graph so that the maximum possible rate of reaction could be reached.

The problem of the delay between pouring in the Hydrogen Peroxide, bunging the test tube and starting the stopwatch could have been limited by getting another person to start the stopwatch when the hydrogen peroxide was poured into the tube.


This is a real A-level school project and as such is intended for educational or research purposes only. Extracts of this project must not be included in any projects that you submit for marking. Doing this could lead to being disqualified from all the subjects that you are taking. You have been warned. If you want more help with doing your biology practicals then have a look at 'Advanced Level Practical Work for Biology' by Sally Morgan. If you want more detailed biology information then I'd recommend the book 'Advanced Biology' by M. Kent.


This entry was posted on Thursday, June 5th, 2008 at 8:12 pm and is filed under Life. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.

13 Responses to “The Effect Of Substrate Concentration On The Activity Of The Enzyme Catalase”

Would it be possible to have the same/a similar title for my coursework? this is very helpful. Would be great to use this is a guideline. Obviously not to copy.

Hi H.H, yes you can use this title. It isn’t my title – it was actually a title set by the exam board during the year I did my A-Levels. Good luck with your coursework.

Am I allowed to use this for secondary data for my controlled assessment?

Hi Zoë, yes you can use the data as long as you reference this web page. Good luck!

Hi! I was wondering how i could reference this page in APA format. Since I don’t have an author’s name, I can barely reference this page properly…. Thanks!

The reaction that breaks down large molecules into smaller moleculs is catabolism not anabolic reaction.

and also, shouldnt your graph’s x axis title be ‘concentration of hydrogen peroxide’ instead of ‘concentration of yeast’?

No. The x axis is fine. Because he adds water to the yeast not to the peroxide to change the concentration. So the indepent variable is the yeast and the indepent variable should be the x-axis!

Its catabolic reaction not anabolic.

as my bio teacher says

As the concentration increased , the amount of oxygen decrease? Why you wrote that it is directly proportional?

Hi I was just wondering how to cite this page all I got is the page name there is barely anything to cite can you help me

Hi Skye, you could just cite the page URL, and page title. Thanks.

Seems to be useful article but on some points your not correct.
forexample you said

“This type of reaction where a molecule is broken down into smaller pieces is called an anabolic reaction”.

What I know is that this type of reaction should be catabolism and not anabolism as you said.
anabolism and catabolism are two types of metabolism where the anabolism being building reaction and the catabolism being breaking reaction

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