Chemistry of Organisms 9 - BIOLOGY JUNCTION

Catalase Peroxide Lab

Enzyme Rate of Catalase

Introduction:

Enzymes are molecular substances found in cells. Enzymes act as catalysts and most are proteins. Enzymes bind temporarily to one or more of the reactants of the reaction they catalyze. In doing so, they lower the amount of activation energy needed and thus speed up the reaction.
Not only do enzymes economize energy usage, but also provide a variety of other functions. Cells uses an enzyme (catalase) to rid itself of a poisonous substance (hydrogen peroxide). The rate at which this occurs depends on the amount of catalase that is available. In this lab we are going to measure the time it takes for a disc of filter paper, soaked with different concentrations of enzyme, to make its way to the top of a plastic vial filled with peroxide. Rate of enzyme activity = distance (depth of hydrogen peroxide in mm)/time (in sec).

Catalase catalyzes the decomposition of hydrogen peroxide into water and oxygen. One molecule of catalase can break 40 million molecules of hydrogen peroxide each second.

catalase
2H2O2 —–> 2H2O + O2

Objectives:

Students will prepare various dilute solutions from a 100% enzyme solution.

Students will determine how enzyme concentration affects reaction rate.

Materials:

6 medicine cups for dilutions, *catalase stock solution, clear plastic vial, forceps, 18 filter paper disks, Hydrogen Peroxide (H2O2), paper towel, apron, safety glasses, watch with second hand, marker, metric ruler, calculator

* The enzyme has been prepared for you as follows: 50g of peeled potato was mixed with 50 ml cold distilled water and crushed ice and homogenized in a blender for 30 seconds. This extract was filtered through cheesecloth and cold distilled water was added to a total volume of 100 ml. Extract concentration is arbitrarily set at 100 units/ml. ENZYME SHOULD BE KEPT ON ICE AT ALL TIMES!!

Procedure:

Make a series of dilutions of the enzyme catalase using the following table.

Final Quantity Needed	Concentration of Final Solution	mL of Catalase	mL of Water
10 ml	100%	c10	0
10 ml	80%	8	2
10 ml	60%	6	4
10 ml	40%	4	6
10 ml	20%	2	8
10 ml	0%	0	10

Use a marking pencil and mark the enzyme solutions as follows: 100%, 80%, 60%, 40%, 20%, and 0%.
Fill a clear vial with 20 mL of hydrogen peroxide.
Using your forceps, pick up one filter paper disk and submerge it in the 100% enzyme solution for 5 seconds. Continue to hold the disk with the forceps.
Using your forceps, pick up one filter paper disk and submerge it in the 100% enzyme solution for 5 seconds. Continue to hold the disk with the forceps.
Remove the disk from the solution and blot it dry, for five seconds, using your paper towel.
Drop the disk in the hydrogen peroxide and measure the time it takes for the disk to rise up from the bottom. Begin timing as soon as the disk touches the surface of the hydrogen peroxide.
Use the metric ruler to measure the distance the disk sinks into the hydrogen peroxide. multiply by two to determine the entire distance the disk traveled. Enter the time and distance the disk traveled in the column for Trial 1 in the data table below.

% Catalase	Time in seconds				Distance in millimeters				Reaction Rate mm/s
	Trial 1	Trial 2	Trial 3	Avg.	Trial 1	Trial 2	Trial 3	Avg.
100
80
60
40
20
0

Repeat the above steps for the remainder of the solutions. Remember to use clean filter paper each time you use a different solution. Enter the times and distances for trial 2 and 3 in their appropriate columns.

Analysis & Conclusion:

1. Which concentration of catalase had the fastest reaction time?

2. Which concentration of catalase had the slowest reaction time?

3. What is catalase & why is it important to cells in your body?

4. How did you know that catalase was present in the above compounds?

5. What 2 substances form when catalase breaks down hydrogen peroxide?

6. What type of organic compound is catalase?

7. Produce a line graph of the above data. Use the enzyme concentration as the independent variable and the reaction rate as the dependent variable.

Graph Title:__________________________________________________

Legend:

8. Based on the graph and overall slope of the line, what can you conclude about the effect of enzyme concentration on reaction rate?

Bioenergetics Powerpoint Worksheet

Bioenergetics
ppt Questions

Energy

1. What is bioenergetics?

2. All organisms require ____________ to perform their functions.

3. Name the 2 main kinds of energy.

4. What is kinetic energy?

5. Give 2 examples of kinetic energy.

6. What is potential energy?

7. Potential energy is stored in ____________ __________.

Two Types of Energy Reactions

8. What is an endergonic reaction?

9. Give an example of an endergonic reaction.

10. What serves as the energy for photosynthesis?

11. During photosynthesis, the light energy is stored in the chemical bonds of what sugar?

12. What are the two raw materials (reactants) for photosynthesis?

13. What is an exergonic reaction?

14. Give an example of an exergonic reaction.

15. Where does the energy for cellular respiration come from?

16. Energy released during cellular respiration that can be used by cells is called _________.

Metabolic Reactions of Cells

17. Define metabolism of cells.

18. From what compound do animals get their energy (ATP) to do cellular work?

19. Name the 2 types of metabolism.

20. Explain anabolic pathways and give an example.

21. Explain catabolic pathways and give an example.

22. The energy that drives catabolic pathways in organisms comes from breaking _____________ ___________ and producing the energy molecule ___________.

Cellular Energy – ATP

23. Name the 3 components that make up ATP.

24. How many phosphate groups are in ATP?

25. The last two phosphate groups on ATP are bonded with ___________ ___________ bonds.

26. Which phosphate bond contains the MOST energy?

27. Give the formula for a phosphate group.

28. Name the process that breaks the bonds of ATP to release energy.

29. How often does phosphorylation occur in cells?

30. What enzyme weakens the last phosphate bond so it can be broken?

31. Organisms use ___________ to break down energy-rich __________ to release the potential energy stored in its bonds.

32. Energy released from the chemical bonds of glucose are trapped & stored in ________ until a cell needs energy.

33. What does ATP stand for?

34. How much ATP do cells use?

35. What coupled reactions make ATP and then release its energy.

36. Is hydrolysis exergonic or endergonic?

37. Is energy stored or released during hydrolysis?

38. Is dehydration exergonic or endergonic?

39. Is energy stored or released in dehydration?

40. When ATP is broken down to release energy, what two things form?

41. During hydrolysis of ATP, a molecule of ___________ is added to split the ________ phosphate bond.

42. What happens to the energy released from the hydrolysis of ATP?

43. During dehydration of ATP, a molecule of ___________ is removed to join a free phosphate and __________ making more ATP again.

44. Where is the energy stored in the dehydration process to form ATP?

Review

45. How many high-energy phosphate bonds does ATP have?

46. Is photosynthesis anabolic or catabolic?

47. Is photosynthesis exergonic or endergonic?

48. The breakdown of ATP is due to hydrolysis or dehydration?

49. Water is added or removed in the breakdown of ATP?

50. Which of the following are coupled reactions in organisms:

a. hydrolysis – dehydration?

b. Anabolism – Catabolism?

c. Endergonic – Exergonic?

AP Lecture Guide 02 & 03 – Chemical Context of Life & Water

AP Biology: CHAPTERS 2 & 3

CHEMICAL CONTEXT OF LIFE & WATER

1. What are the most common elements in the human?

__________________________________________________________________________

2. Helium has an atomic number of 2 and atomic mass of 4. Explain.

__________________________________________________________________________

3. Define isotope and give some examples.

__________________________________________________________________________

4. How are isotopes used in biology?

__________________________________________________________________________

5. What happens when electrons change levels?

__________________________________________________________________________

6. What is the significance of valence numbers?

__________________________________________________________________________

7. Why do atoms form covalent vs. ionic bonds?

__________________________________________________________________________

8. How do non-polar covalent bonds differ from polar covalent bonds?

__________________________________________________________________________

9. What is a hydrogen bond? How does it form and how is it different from a covalent bond?

__________________________________________________________________________

10. Sketch a few molecules of water, indicate their polarity, and where H bonds form.

11. Why is H bonding so important to water’s properties?

__________________________________________________________________________

12. List the “special” properties of water and give an example of why the property may be

important to living things.

a. ________________________________________________________________________

__________________________________________________________________________

b. ________________________________________________________________________

__________________________________________________________________________

c. ________________________________________________________________________

__________________________________________________________________________

d. ________________________________________________________________________

__________________________________________________________________________

Amino Acids

Listed below are the common names and structural formulas of the twenty amino acids found in proteins. They are arranged alphabetically.

alanine

arginine

asparagine

aspartic acid

cysteine

glutamic acid

glutamine

glycine

histidine

isoleucine

leucine

lysine

methionine

phenylalanine

proline

serine

threonine

tryptophan

tyrosine

valine

Amylase on Starch Lab

Enzyme Amylase Action on Starch

INTRODUCTION:

In this experiment you will observe the action of the enzyme amylase on starch. Amylase changes starch into a simpler form: the sugar maltose, which is soluble in water. Amylase is present in our saliva, and begins to act on the starch in our food while still in the mouth.
Exposure to heat or extreme pH (acid or base) will denature proteins. Enzymes, including amylase, are proteins. If denatured, an enzyme can no longer act as a catalyst for the reaction.
Benedict’s solution is a test reagent that reacts positively with simple reducing sugars like maltose, but will not react with starch. A positive test is observed as the formation of a brownish-red cuprous oxide precipitate. A weaker positive test will be yellow to orange.

MATERIALS:

Cornstarch
Distilled water
Saliva
Vinegar
Benedict’s qualitative solution
3 graduated cylinders (10mL)
250-ml beaker
Stirring rod
3 test tubes (16 x 125mm)
Test tube rack
Wax pencil
Water Bath

PRE-LAB:

Add 1g of cornstarch to a beaker containing 100ml of cold distilled water. While stirring frequently, heat the mixture just until it begins to boil. Allow to cool.

PROCEDURE:

1. Fill the 250-mL beaker about 3/4 full of water and place on the hot plate for a boiling water bath. Keep the water JUST AT BOILING.

2. Mark 3 test tubes A, B and C. “Spit” between 1 and 2 mL of saliva into each test tube.

3. Into tube A, add 2 mL of vinegar. Into tubes B and C, add 2 mL of distilled water. Thump the tubes to mix.

4. Place tube B into the boiling water bath for 5 minutes. After the five minutes, remove from the bath, and place back into the test tube rack.

5. Add 5 mL of the starch solution to each tube and thump to mix. Allow the tubes to sit for 10 minutes, occasionally thumping the tubes to mix.

6. Add 5 mL of Benedict’s solution to each tube and thump to mix. Place the tubes in the hot water bath. The reaction takes several minutes to begin.

OBSERVATIONS:

Tube A: Starch + saliva treated with vinegar (acid)

What does this indicate?__________________________________________________

____________________________________________________________________

Tube B: Starch + saliva and water, treated in a boiling water bath

What does this indicate?__________________________________________________

____________________________________________________________________

Tube C: Starch + saliva

What does this indicate?__________________________________________________

____________________________________________________________________

QUESTIONS:

1. What is the function of an enzyme?

2. Where does a substrate attach to an enzyme?

3. If an enzyme is present in a reaction, less ________________ _________________ will be needed to get the reaction started.

4. What is a common suffix found at the end of most biological enzymes?

5. Most enzymes are macromolecules called ________________.

6. Define denaturation of proteins.

7. Name 3 things that can denature or unfold an enzyme.

8. In this lab, what weak acid denatured the protein?

9. What was the purpose of placing one test tube in a hot water bath?

10. What happens to enzymes in your body whenever you run fever?