Yeast Catalase

Introduction:

The main purpose of our project is to learn about enzymes and how they function as biological catalysts in certain environmental conditions.

The driving question of our project is 'What are enzymes and why are they vital to living things?'

Hypothesis: If we add yeast in warm water to hydrogen peroxide, then it will act as an enzyme to break down hydrogen peroxide and release oxygen. The yeast will not work with boiling water, or without hydrogen peroxide.

Materials:

• • Empty 16-ounce Plastic Bottle (soda bottle or water bottle)

• Tray or Foil Pan

• Measuring Cup or Beaker, 50 mL or 100 mL

• Hot plate or Microwave

• 3% Hydrogen Peroxide, 100 mL per reaction

• Warm water, 50 mL per reaction

  • Water, 100 mL

  • Dry Active Yeast, 1 packet per reaction

  • Dish Detergent

  • Food Coloring (3 colors)

Procedures:

• 1. Place 100 mL of 3% hydrogen peroxide into an empty 16-oz plastic bottle.

  2. Add at least 1 teaspoon of dish detergent into the bottle.

  3. Add 1 drop of food coloring into the bottle.

  4. Mix one packet of dry active yeast with 50 mL of warm water in a cup or a beaker.

  5. Place the plastic soda bottle into a tray or a foil pan.

  6. Pour the yeast mixture into the bottle with hydrogen peroxide.

  7. Observe and record the results.

  8. Then, place 100 mL of water into an empty 16-oz plastic bottle.

  9. Add at least 1 teaspoon of dish detergent into the bottle.

  10. Add 1 drop of different food coloring into the bottle.

  11. Mix one packet of dry active yeast with 50 mL of warm water in a cup or a beaker.

  12. Place the plastic soda bottle into a tray or a foil pan.

  13. Pour the yeast mixture into the bottle with hydrogen peroxide.

  14. Observe and record the results.

  15. Then, place 100 mL of 3% hydrogen peroxide into an empty 16-oz plastic bottle.

  16. Add at least 1 teaspoon of dish detergent into the bottle.

  17. Add 1 drop of different food coloring into the bottle.

  18. Heat 50 ml of water until it starts to boil.

  19. Mix one packet of dry active yeast with 50 mL of boiling water in a cup or beaker.

  20. Place the plastic soda bottle into a tray or foil pan.

  21. Pour the yeast mixture into the bottle with hydrogen peroxide.

  22. Finally, observe and record the results.

Safety:

• • Wear safety goggles when performing experiments so that your eyes won't be harmed in the process of the reaction.

  • Use caution when working with a hot plate.

  • Use protective heat-resistant gloves to handle hot glassware so that your palms and fingers won't get burned in the process of handling these equipment.

  • Never ever eat or drink materials used in experiments so that you won't die of poisoning or get sick.

Action Video:

• • • • • • Part I of the experiment involves the mixing of a yeast mixture (warm water + yeast) with 100 mL of hydrogen peroxide.

• • • • • • • • Part II of the experiment involves the mixing a yeast mixture (hot water + yeast) with 100 mL of hydrogen peroxide.

• • As soon as the mixture makes contact with the hydrogen peroxide, it begins to foam and rise rapidly. It has a whitish color. After a few seconds, it rises out of the bottle and on to the tray.

Yeast cells contain an enzyme called 'catalase'.What does catalase do? How does the function of catalase relate to the observations in the previous demonstration?

• • Catalase is an enzyme that catalyzes the decomposition of hydrogen peroxide to water and oxygen, the enzyme is very important because it protects the cell from oxidative damage.

What do you observe if the soda bottle has 100 mL of water, instead of hydrogen peroxide?

• • The reaction would not occur. The enzyme, catalase, works only with hydrogen peroxide because it is substrate specific. If hydrogen peroxide is not present, we would not achieve the same results.

Enzymes are very specific. Use the terms, 'active site', 'substrate', and 'enzyme-substrate complex' to explain the results of the demonstrations that used hydrogen peroxide compared to the one that used water.

• • Enzymes are substrate specific. They only work with certain types of substrates. The enzyme is shaped in such a way that only one substrate can fit. The place where the enzyme and substrate meet is called the active site. It is often compared to a key and a lock. The substrate for catalase is hydrogen peroxide. Catalase will not work with anything else. That's why nothing happened in Part 3, where there was only water. This is called the enzyme substrate complex.

What chemical equation summarizes the reaction catalyzed by catalase? Draw a series of pictures to represent a model for the reaction and the enzyme's role in the reaction.

• • The equation is 2H₂O₂ -> 2H₂O + O₂.

What do you observe if you use boiled yeast mixture in the demonstration?

• • The reaction occurs slowly when it is too hot because the enzyme, which is responsible for speeding up the reaction, becomes denatured.

What type of molecule are enzymes? Describe the basic structure of this type of molecule.

• • Enzymes are large protein molecules. Their active sites are shaped so only their substrate can fix.

Heat can cause 'denaturation'. What does this mean? Why would a denatured enzyme no longer function properly?

• • Enzymes have a certain range of temperatures where they work best. If it's too hot, the enzyme will become denatured. Denaturation is the process of removing or destroying the natural qualities/functions of the enzyme. When the enzyme is denatured, the qualities will be destroyed, so the enzyme will not function properly. This means that the enzyme will no longer be able to speed up the reaction.

What are everyday examples of the effect of heat on protein structure?

• • When we boil eggs, we are denaturing the proteins so that it will be easier for our body's enzymes to speed up the digestion process.

What enzymes participate in the digestion of food in the human body? Identify the name, location, and substrate of each.

• 1. Lactase participate in the digestion of things like milk and other things that contain lactose, which is its substrate. This happens in the small intestine.

  2. Another enzyme is Amylase, who's substrate is starch. This is found in the mouth in the form of saliva.

  3. Sucrase's substrate is sucrose, found in all sugars. It's released in the small intestine.

Synthesis Questions:

1. The human body has thousands of different enzymes. Why does the body need so many different types of enzymes?

   • Enzymes are proteins that control the speed of chemical reactions in your body. If these enzymes weren't present, then the reactions would be too slow to keep you alive.

• 1. Many organisms, such as fungi, animals, and plants, have catalase. What does this indicate about the enzyme?

     • This might mean that they must have been present in previous generations of that living. This means that the gene code has been persevered for a long time. They can help in speeding up reactions in specific areas. Catalase is an enzyme that catalyzes the reduction of hydrogen peroxide.

  2. How does the environment affect enzyme function? How is this different than the relationship between an organism's DNA and its enzymes?

     • The temperature, pH levels and other minor changes can affect the functionality of the enzymes.

  3. What are some ways you can get the decomposition reaction of hydrogen peroxide to occur even faster in the initial plastic bottle demonstration you performed? Explain your reasoning for each suggestion you provide.

     • You can get the decomposition of hydrogen peroxide to occur even faster by keeping the catalase at an optimum temperature because as the temperature rises, reacting molecules have more and more kinetic energy. Another way is by keeping the catalase at its optimum pH which can affect the enzyme's shape and its effectiveness.

  4. Would you expect viruses to have enzymes such as catalase? Why or why not?

     • No, because viruses are not living and they do not posses the metabolic processes of a cell.

  5. After slicing an apple, the slices turn brown after a short time. This is due to an oxidation reaction that is catalyzed by an enzyme present in the tissue of the fruit. The reaction requires oxygen, which the slices are exposed to when the apple is cut. Propose two ways to slow the reaction and keep the slices fresh for a longer period of time. Explain your reasoning for each proposal.

     • Seal it up in a bag, so less oxygen will go in and affect the enzymes. And also store it in the fridge so that the enzymes are cold in enough to slow down the reaction rate by a lot.