A+ Answers Biology

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The Merrell drug company that tried to bring thalidomide to the United States also marketed a cholesterol inhibitor with serious side effects for 5,000 people. Two Merrell employees were fined $80,000 and the company made an $18 million profit. What had the company done wrong?
A. Substituted the results for a tested drug for an untested drug
B. Forged signatures on test reports
C. Failed to disclose that the drug caused blindness in lab animals
D. Testified that testing had been done when it had not
Question 2
A criticism of the caveat emptor doctrine is:
A. too much government regulation.
B. reduced profit for businesses.
C. it hurts consumers by raising prices.
D. latent defects.
Question 3
Some of the worst con artists practice their craft based on meteorological events. These are known as ________ con artists.
A. event
B. disaster
C. weather
D. special occasion
Question 4
The term laissez faire refers to the concept that:
A. governments should not interfere with free markets.
B. consumers should be protected from fraud artists.
C. buyers should be aware of offers that sound too good to be true.
D. marketers should be fair to consumers.
Question 5
The following companies have all been accused of fraud involving car problems and possible solutions EXCEPT:
A. Ford.
B. Kmart.
C. Goodyear.
D. Firestone.
Question 6
The telemarketing scam which relies on use of a certain area code to make money just from phone calls is _____ calls.
A. 777
B. 900
C. 666
D. 888

Question 7
The Food and Drug Administration has cited evidence that nicotine is an addictive drug 5 to 10 times more potent than:
A. cocaine.
B. crack.
C. heroin.
D. marijuana.
Question 8
Telemarketers target all of the following groups EXCEPT:
A. family members of AIDS victims.
B. the bereaved.
C. those worried about dependence on foreign oil.
D. college students living away from home for the first time.
Question 9
Ford decided that repairs would not be cost effective, based on a comparison of total repair costs for all Pintos and:
A. statistical likelihood of plaintiffs winning lawsuits.
B. profit margin for the Pinto automobile.
C. total of Pinto projected sales.
D. total of average lawsuit settlements for serious burn injuries and burn deaths.
Question 10
Tobacco companies have used specific marketing campaigns with flavored cigarettes, new packages, and posters at fast food restaurants to target:
A. Hispanics.
B. African Americans.
C. women.
D. teenagers.
Question 11
A boiler room might be characterized by:
A. telephones.
B. well-dressed salesmen.
C. support personnel.
D. fancy furniture.
Question 12
In 1999, Susan Collins described the predatory practices of sweepstakes companies as “increasingly deceptive and increasingly aggressive.” She made these remarks:
A. as chairman of a Senate committee.
B. during a television news magazine segment.
C. in testimony before a Congressional committee.
D. in a nationally syndicated newspaper column.

Question 13
Despite inadequate testing, H.R. Robins marketed __________, which caused death, birth defects, miscarriages, and blindness in infants.
A. the intrauterine birth control device
B. the diaphragm
C. birth control pills
D. the birth control patch
Question 14
Fen-phen, Bendectin, and thalidomide were all approved by the FDA and prescribed to patients. Which one of these drugs is alleged to cause valvular heart disease?
A. Thalidomide
B. Bendectin and thalidomide
C. Bendectin
D. Fen-phen
Question 15
American Family Publishers used all of the following techniques to trick entrants EXCEPT:
A. free merchandise.
B. small print.
C. YOU’RE OUR NEWEST $12 MILLION WINNER.
D. backgrounds that made print difficult to read.
Question 16
A practice known as dumping involves:
A. disposal of hazardous materials in unapproved sites.
B. selling dangerous products in foreign countries after a domestic ban.
C. donating unsafe products to charities for a tax deduction.
D. selling products to discount outlets when defects are discovered.
Question 17
Five to 10% of all minutes logged on the telephone time scams are concentrated in:
A. psychic hotlines.
B. music sales.
C. work-at-home offers.
D. sex lines.
Question 18
Pursuant to an agreement, American Family Publishers agreed to eliminate which slogan from its advertising:
A. “Win! Win! Win!”
B. No Purchase Necessary
C. “Millions in Prizes!”
D. “You’re Our Next Winner!”
Question 19
The number one consumer complaint concerning fraud involves:
A. refinance loans.
B. home improvement.
C. auto repair.
D. telemarketing.
Question 20
__________ of the most dangerous problems that led to recalls of children’s products were never voluntarily reported to the government.
A. 75%
B. 60%
C. 50%
D. 25%

 
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Chapter 6: DNA, The Molecule of Life

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Name:       Sec:

 

Chapter 6: DNA, The Molecule of Life

 

Module 6.1. DNA is a polymer of nucleotides.

1. The molecule of heredity is      .

2. Which of the following is used to construct DNA?

A) |_| chromosomes

B) |_| nucleotides

C) |_| double helix

D) |_| carbohydrates

 

3. Create double stranded DNA, by filling in the complementary bases:

A

T

T

G

A

C

4. Match the following terms with their appropriate descriptions: double helix, nucleic acid, nucleotide, backbone.

A) Molecules that contain information to make proteins

B) Consists of a base, five-carbon sugar, and a phosphate

C) Structure of a double-stranded molecule of DNA

D) Identical among all DNA molecules

 

 

5. Complete the following diagram of a nucleotide with the terms: phosphate group, sugar group, base group:

     

 

 

 

 

 

 

 

6. Overall, a molecule of DNA has a negative charge. Which component of DNA gives it this charge?

 

7. A gene is a specific section of DNA that contains the instructions to make a protein. If all molecules of DNA contain a phosphate group, a deoxyribose, and a base, propose an explanation for how the information to make a protein is coded within the DNA molecule.

 

8. If thymine makes up 20% of the bases in a DNA double helix, what percentage of the bases is guanine?

A) |_| 80%

B) |_| 60%

C) |_| 30%

D) |_| 20%

 

 

Module 6.2. During DNA replication, a cell duplicates its chromosomes.

9. If one polynucleotide strand of DNA has ACTTGACTAGCTA as its sequence of bases, what would be the sequence of bases on the opposing strand?

 

10. True or False; If false, make a true statement: DNA must be precisely copied prior to being passed on to the next generation

 

11. The process by which a molecule of DNA is copied is known as      .

 

 

12. Complete the following diagram, which illustrates the nature of DNA replication. Use the following terms: parent double-stranded DNA, daughter double-stranded DNA, template strands, newly synthesized strands. Note some terms may be used more than once.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

13. The following diagram uses colors to illustrate the replication of a chromosome. Use your knowledge of DNA replication to determine whether or not the illustration is accurate. If it is not accurate, briefly explain how to make it correct.

UN_06_004

 

14. Place the following steps of DNA replication in the proper order: DNA fragments are fused together; double helix is pulled apart; new strands of DNA are synthesized.

1.

2.

3.

 

15. A drug that inhibits DNA ligase but not DNA polymerase is added to a cell. Explain how DNA replication would be affected as a result of this drug.

 

Module 6.3. DNA directs the production of proteins via RNA.

16. True or False; if false make a true statement: Nucleic acids store the information to make carbohydrates.

 

17. Two types of nucleic acids that are found in all cells are       and      .

 

18. Which of the following is found in all nucleotides?

A) |_| Phosphate group

B) |_| Ribose

C) |_| Deoxyribose

D) |_| Uracil

 

 

19. Is the following diagram a nucleotide of DNA, RNA, or could it be either one? Briefly explain your answer.

 

20. Complete the following table, which compares and contrasts the structures of DNA and RNA.

  DNA RNA
Unique to…

Common both DNA and RNA

 

21. Certain viruses, like HIV, actually contain RNA. When a virus of this type takes over a host cell, it makes DNA from its RNA. The viral DNA is then used to make an RNA copy, which is used to make viral proteins. In all cells, the flow of genetic information is from DNA RNA proteins. What is the flow of information in viruses (which are not considered cells) like HIV?

 

 

22. You are a biochemist and have been given a test tube containing a small amount of nucleic acid. You have been asked to determine whether it is DNA or RNA. Which of the following would be a characteristic that indicates RNA? Hint: There may be more than one correct answer.

A) |_| Presence of uracil, but no thymine

B) |_| Presence of guanine, but no cytosine

C) |_| Presence of phosphate, but no nitrogen

D) |_| Presence of ribose, but no deoxyribose

 

Module 6.4. Genetic information flows from DNA to RNA to protein

23. True or False; If false, make a true statement: The nucleotide sequence in DNA through the process of information flow comes to produce your characteristics.

 

24. Correct the following: RNA protein DNA

     

 

25. Complete the following diagram, which represents the flow of genetic information in a cell. Use the terms: transcription, translation, DNA, RNA, protein, ribosome, nucleus, cytoplasm, nuclear membrane, nuclear pore. Note that “D” is on the structure behind the arrow, and “E” is on the arrow.

UN_06_007

 

J

I

 

 

G

 

 

 

H

F

E

D

C

B

A

 

 

 

 

 

 

 

 

 

 

 

a.       f.

b.       g.

c.       h.

d.       i.

e.       j.

 

26. Translation converts the information stored in       into      .

A) |_| DNA; RNA

B) |_| RNA; a protein

C) |_| protein; DNA

D) |_| protein; RNA

 

 

27. Briefly explain why you think “mRNA” is a good name for the RNA copy made from DNA.

 

28. Complete the following table, which compares transcription and translation.

  Transcription Translation
Location

Description

 

29. If a strand of DNA has the sequence AAGCTC, transcription will result in which of the following?

A) |_| Single RNA strand with the sequence TTCGAG

B) |_| DNA strand with the sequence TTCGAG

C) |_| Single RNA strand with the sequence UUCGAG

D) |_| DNA strand with the sequence AAGCTC

 

30. A series of three nucleotides that specifies an amino acid is a(n)      .

 

31. A student is given a sequence of DNA as follows: AACTAGCTAGCT, and is asked to provide the mRNA copy that would be made from that sequence during transcription. The student provides the following sequence: TTGATCGATCGA. Is this the correct sequence? If not, explain why it is incorrect and fix it.

 

Module 6.5. Transcription creates a molecule of RNA from a molecule of DNA

 

32.       is the process by which information stored in DNA is copied into mRNA.

 

33. List the following steps of transcription in order: RNA polymerase makes RNA; mRNA leaves the nucleus; RNA polymerase binds the promoter; RNA splicing.

1.

2.

3.

4.

 

34. Complete the following diagram, which illustrates the process of transcription. Use the terms: DNA polymerase, promotor, DNA

UN_06_008

C

B

A

 

 

 

 

 

 

 

 

a. 

b. 

c. 

 

35. The template strand is the DNA strand directly used by the RNA polymerase to make the RNA copy. You are given the following mRNA sequence: AUGCUGAUU. Are you able to determine the sequence of bases on the DNA strand that was not transcribed? Briefly explain your answer either way. (Note: DNA is double stranded. During replication it is unwound and only one strand serves as the template strand. You are being asked if you can determine the sequence of the non-template strand).

 

36. A gene has a sequence of DNA in front of it that directs the RNA polymerase where to begin transcription. This sequence of DNA is the:

A) |_|transcription

B) |_|promoter

C) |_|terminator

D) |_|RNA splicing

 

 

37. You are a graduate student at the University of Iowa and working as a teaching assistant for a freshman introductory biology course. Two of your students have come to you with a question about the sequence of an mRNA transcribed from a gene. The original DNA sequence from which the mRNA was transcribed reads: TGACGATCGTA. The students were asked to provide the sequence of bases in the mRNA and came up with the following mRNA sequence: ACTGCTAGCAT. They are confused because their answer does not match the answer in the book. Briefly explain the very common mistake they made and what the correct sequence would be.

 

38. True or False; If false, make a true statement: The terminator is the sequence of DNA in front of the gene that tells the RNA polymerase where to begin transcription.

 

39. List three ways in which mRNA is modified after transcription:

1.

2.

3.

 

40. Are introns and exons found in DNA or RNA?

 

Module 6.6. Translation involves the coordination of three kinds of RNA.

 

41. True or False; If false, make a true statement: The process of translation occurs within the cytoplasm on a cellular structure known as the mitochondrion.

 

 

42. Which of the following RNA molecules is a component of ribosomes?

A) |_| mRNA

B) |_| rRNA

C) |_| tRNA

D) |_| All of the above

 

43. A set of three nucleotides that specifies an amino acid is called a(n)      .

 

 

44. Which of the following RNA molecules is involved in the process of translation?

A) |_| mRNA

B) |_| rRNA

C) |_| tRNA

D) |_| All of the above

 

45. Complete the following diagram, which illustrates a ribosome:

UN_06_010

 

 

 

 

 

46. Complete the following table, which compares the different kinds of RNA.

  mRNA rRNA tRNA
Function

 

47. Briefly explain why a molecule of tRNA makes a good translator during the process of translation. Be sure to use the terms codon, anticodon, amino acid.

     

 

 

48. According to the table of the genetic code shown here, changing the second base of the codon

A) |_| always changes the amino acid that is encoded.

B) |_| never changes the amino acid that is encoded.

C) |_| sometimes changes the amino acid that is encoded.

D) |_| changes all of the above as noted.

 

49. What codon does every mRNA molecule have in common? What amino acid begins every polypeptide? Use the chart below:

UN_06_011

 

 

50. Match the description to the molecule(s). Each choice should be used only once.

A. DNA

B. mRNA

C. tRNA

D. More than one of the above.

E. None of the above.

A molecule of this will always have an equal percentage of A and G, and an equal percentage of C and T

Has an anticodon and carries an amino acid

Serves as a messenger for taking genetic information from the nucleus to the cytoplasm

Is involved in the process of translation

Is a component of ribosomes

 

51. How many codons are in the following mRNA sequence:

AUGGGGCAGGUAUGA

52. Use the information from question 49 to determine how many amino acids would be in the polypeptide produced from that mRNA.

 

Module 6.7. Translation creates a molecule of protein via the genetic code

 

53. True or False; If false, make a true statement: Ribosomes are part of the cytoplasm.

 

54. Place the following steps of translation in order: elongation, termination, initiation.

1.

2.

3.

 

55. Translation takes place in the ______ on a _________.

A) |_| nucleus; ribosome

B) |_| cytoplasm; ribosome

C) |_| nucleus; mitochondria

D) |_|cytoplasm; lysosome

 

56. A drug that changes the AUG codon to UAC would most likely have what effect on translation? Be brief but specific in your answer.

 

57. If three DNA bases of the template strand are AGT, what is the anticodon of the tRNA that brings the amino acid?

A) |_| UCA

B) |_| TCU

C) |_| AGU

D) |_| TCA

 

58. Complete the following table, which compares the different stages of translation.

  Initiation Elongation Termination
Description

 
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Anthropology Mini Essays

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Essay Questions

Both of the following questions will appear on your exam. You can best prepare for the essay question by writing out your answer to each one and practicing it as you study. An added benefit of doing this is that you will also be reviewing key concepts that will be useful for the rest of the exam.

 

1.     Darwin originally believed that natural selection could not be seen in action. Today we know this is not the case. Explain one specific example of natural selection in action discussed in course materials. In order to completely address this question, you must include a clear description of how natural selection works and how the example illustrates natural selection. Be sure to choose an example with enough information to completely address the question. 2-3 substantial paragraphs.

 

 

2.     Evolutionary theory predicts that deleterious conditions will be selected out of populations and, therefore, occur at a very low rate. However, certain genetic diseases are more common in some populations than others and natural selection can explain this variation. Using Tay-Sachs or sickle-cell anemia as your example, explain why these diseases are more common in some populations than others. Be specific. 2-3 substantial paragraphs.

 

RESOURCES TO USE (You don’t have to use all, but choose a few that are relevant) :

1. http://www.smithsonianmag.com/smithsonian-institution/moral-dilemma-we-face-age-of-humans-180952909/?no-ist

2.https://www.psychologytoday.com/blog/busting-myths-about-human-nature/201403/why-normal-is-myth

3.http://www.hhmi.org/biointeractive/origin-species-beak-finch

4.https://www.sierracollege.edu/ejournals/jscnhm/v2n2/EvolutionAction.html

5.https://www.youtube.com/watch?v=NWqgZUnJdAY&feature=youtu.be

6.http://www.naturalhistorymag.com/features/142195/beyond-dna-epigenetics

7.https://www.psychologytoday.com/blog/busting-myths-about-human-nature/201401/genes-are-not-fortune-tellers

8.https://www.youtube.com/watch?v=i9a-ru2ES6Y&feature=youtu.be

9.https://www.avert.org/professionals/history-hiv-aids/origin#footnote9_ygu9xti

10.http://evolution.berkeley.edu/evolibrary/article/medicine_01

11.http://www.hhmi.org/biointeractive/aids-evolution-epidemic

 

 

 
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UMUC Biology 102/103 Lab 4: Enzymes

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Your Full Name:

UMUC Biology 102/103

Lab 4: Enzymes

INSTRUCTIONS:

 

·         On your own and without assistance, complete this Lab 4 Answer Sheet electronically and submit it via the Assignments Folder by the date listed in the Course Schedule (under Syllabus).

·         To conduct your laboratory exercises, use the Laboratory Manual located under Course Content. Read the introduction and the directions for each exercise/experiment carefully before completing the exercises/experiments and answering the questions.

·         Save your Lab 4 Answer Sheet in the following format:  LastName_Lab4 (e.g., Smith_Lab4).

·         You should submit your document as a Word (.doc or .docx) or Rich Text Format (.rtf) file for best compatibility.

Pre-Lab Questions

 

  1. How could you test to see if an enzyme was completely saturated during an experiment?

 

  1. List three conditions that would alter the activity of an enzyme. Be specific with your explanation.

 

  1. Take a look around your house and identify household products that work by means of an enzyme. Name the products, and indicate how you know they work with an enzyme.

 

 

Experiment 1: Enzymes in Food

This experiment tests for the presence of amylase in food by using Iodine-Potassium Iodide, IKI. IKI is a color indicator used to detect starch. This indicator turns dark purple or black in color when in the presence of starch. Therefore, if the IKI solution turns to a dark purple or black color during the experiment, one can determine that amylase is not present (because presence of amylase would break down the starch molecules, and the IKI would not change color).

concept_tab_2

Materials

(1) 2 oz. Bottle (Empty)
(1) 100 mL Graduated Cylinder
30 mL Iodine-Potassium Iodide, IKI
Permanent Marker
Ruler
2 Spray Lids
30 mL Starch (liquid)
*Cutting Board

  

*2 Food Products (e.g., ginger root, apple, potato, etc.)
*Kitchen Knife
*Paper Towel
*Saliva Sample
*Tap Water

*You Must Provide

 

Procedure:

  1. Remove the cap from the starch solution. Attach the spray lid to the starch solution.
  2. Rinse out the empty two ounce bottle with tap water. Use the 100 mL graduated cylinder to measure and pour 30 mL of IKI into the empty two ounce bottle. Attach the remaining spray lid to the bottle.
  3. Set up a positive control for this experiment by spraying a paper towel with the starch solution. Allow the starch to dry for approximately one hour (this time interval may vary by location).
  4. In the mean time, set up a negative control for this experiment. Use your knowledge of the scientific method and experimental controls to establish this component (hint: what should happen when IKI solution contacts something that does not contain starch?) Identify your negative control in Table 1.

Note: Be sure to space the positive and negative controls apart from each other to prevent cross-contamination.

  1. When the starch solution has dried, test your positive and negative controls. This step establishes a baseline color scale for you to evaluate the starch concentration of the food products you will test in Steps 7 – 11. Record your results in Table 1.
  2. Select two food items from your kitchen cabinet or refrigerator.
  3. Obtain a kitchen knife and a cutting board. Carefully cut your selected food items to create a fresh surface.
Figure 3: Sample set-up.
Figure 3: Sample set-up.
  1. Gently rub the fresh/exposed area of the food items on the dry, starch-sprayed paper towel back and forth 10 – 15 times. Label where each specimen was rubbed on the paper towel with a permanent marker (Figure 3).
  2. Wash your hands with soap and water.
  3. Take your finger and place it on your tongue to transfer some saliva to your finger. Then, rub your moistened finger saliva into the paper towel. Repeat this step until you are able to adequately moisten the paper towel.

    Note: You should always wash your hands before touching your tongue! Alternatively, if you do not wish to put your hands in your mouth, you may also provide a saliva sample by spitting in a separate bowl and rubbing the paper towel in the saliva. Be sure not to spit on the paper towel directly as you may unintentionally cross-contaminate your samples.

  4. Wait five minutes.
  5. Hold the IKI spray bottle 25 – 30 cm away from the paper towel, and mist with the IKI solution.
  6. The reaction will be complete after approximately 60 seconds. Observe where color develops, and consider what these results indicate. Record your results in Table 1.
Table 1: Substance vs. Starch Presence
Substance Resulting Color Presence of Starch?
Positive Control: Starch Dark Purple Yes
Negative Control : Cellulose Brownish red color  No
Food Product: Apple Dark Purple  yes
Food Product: Potato Dark Purple  yes
Saliva: Amylase Brownish red color  No

 

Post Negative Control -Lab Questions

1.      What were your controls for this experiment? What did they demonstrate? Why was saliva included in this experiment?

2.      What is the function of amylase? What does amylase do to starch?

3.      Which of the foods that you tested contained amylase? Which did not? What experimental evidence supports your claim?

 

4.      Saliva does not contain amylase until babies are two months old. How could this affect an infant’s digestive requirements?

 

5.      There is another digestive enzyme (other than salivary amylase) that is secreted by the salivary glands. Research to determine what this enzyme is called. What substrate does it act on? Where in the body does it become activated, and why?

 

6.      Digestive enzymes in the gut include proteases, which digest proteins. Why don’t these enzymes digest the stomach and small intestine, which are partially composed of protein?

 

Experiment 2: Effect of Temperature on Enzyme Activity

Yeast cells contain catalase, an enzyme which helps convert hydrogen peroxide to water

Figure 4: Catalase catalyzes the decomposition of hydrogen peroxide to water and oxygen.
Figure 4: Catalase catalyzes the decomposition of hydrogen peroxide to water and oxygen.

and oxygen. This enzyme is very significant as hydrogen peroxide can be toxic to cells if allowed to accumulate. The effect of catalase can be seen when yeast is combined with hydrogen peroxide (Catalase: 2 H2O2 → 2 H2O + O2).

In this lab you will examine the effects of temperature on enzyme (catalase) activity based on the amount of oxygen produced. Note, be sure to remain observant for effervescence when analyzing your results.

 

Materials

(2) 250 mL Beakers
3 Balloons
30 mL 3% Hydrogen Peroxide, H2O2
Measuring Spoon
Permanent Marker
Ruler
20 cm String

  

3 Test Tubes (Glass)
Test Tube Rack
Thermometer
Yeast Packet
*Hot Water Bath
*Stopwatch

*You Must Provide

 

Procedure

  1. Use a permanent marker to label test tubes 1, 2, and 3. Place them in the test tube rack.
  2. Fill each tube with 10 mL hydrogen peroxide. Then, keep one of the test tubes in the test tube rack, but transfer the two additional test tubes to two separate 250 mL beakers.
  3. Find one of the balloons, and the piece of string. Wrap the string around the uninflated balloon and measure the length of the string with the ruler. Record the measurement in Table 2.
  4. Create a hot water bath by performing the following steps:
    1. Determine if you will use a stovetop or microwave to heat the water. Use the 100 mL graduated cylinder to measure and pour approximately 200 mL of water into a small pot or microwave-safe bowl (you will have to measure this volume in two separate allocations).
    2. If using a stovetop, obtain a small pot and proceed to Step 4c. If using a microwave, obtain a microwave-safe bowl and proceed to Step 4e.
    3. If using a stove, place a small pot on the stove and turn the stove on to a medium heat setting.
    4. Carefully monitor the water in the pot until it comes to a soft boil (approximately 100 °C). Use the thermometer provided in your lab kit to verify the water temperature. Turn the stove off when the water begins to boil. Immediately proceed to Step 5.

      CAUTION: Be sure to turn the stove off after creating the hot water bath. Monitor the heating water at all times, and never handle a hot pan without appropriate pot holders.

    5. If using a microwave, place the microwave-safe bowl in the microwave and heat the water in 30 second increments until the temperature of the water is approximately 100 °C. Use the thermometer provided in your lab kit to verify the water temperature. Wait approximately one minute before proceeding to Step 5.
  5. Place Tube 1 in the refrigerator. Leave Tube 2 at room temperature, and place Tube 3 in the hot water bath.

Important Note: The water should be at approximately 85 °C when you place Tube 3 in it. Verify the temperature with the thermometer to ensure the water is not too hot! Temperatures which exceed approximately 85  °C may denature the hydrogen peroxide.

  1. Record the temperatures of each condition in Table 2. Be sure to provide the thermometer with sufficient time in between each environment to avoid obscuring the temperature readings.
  2. Let the tubes sit for 15 minutes.
  3. During the 15 minutes prepare the balloons with yeast by adding ÂĽ tsp. of yeast each balloon. Make sure all the yeast gets settled to the bulb of the balloon and not caught in the neck. Be sure not spill yeast while handling the balloons.
  4. Carefully stretch the neck of the balloon to help ensure it does not rip when stretched over the opening of the test tube.
  5. Attach the neck of a balloon you prepared in step 8 to the top of Tube 2 (the room temperature test tube) making sure to not let the yeast spill into the test tube yet. Once the balloon is securely attached to the test tube lift the balloon and allow the yeast to enter the test tube. Tap the bulb of the balloon to ensure all the yeast falls into the tube.
  6. As quickly and carefully as possible remove the Tube 1 (cold) from the refrigerator and repeat steps 9 – 10 with Tube 1 using a balloon you prepared in step 8.
  7. As quickly and carefully as possible remove Tube 3 (hot) from the hot water bath and repeat steps 9 – 10 with Tube 3 using a balloon you prepared in step 8.
  8. Swirl each tube to mix, and wait 30 seconds.
  9. Wrap the string around the center of each balloon to measure the circumference. Measure the length of string with a ruler. Record your measurements in Table 2.
Table 2: Balloon Circumference vs. Temperature
Tube Temperature (°C) Balloon Circumference (Uninflated; cm) Balloon Circumference (Final; cm)
1 – (Cold)      
2 – (RT)    
3 – (Hot)    

 

 

Post-Lab Questions

1.      What reaction is being catalyzed in this experiment?

2.      What is the enzyme in this experiment? What is the substrate?

3.      What is the independent variable in this experiment? What is the dependent variable?

4.      How does the temperature affect enzyme function? Use evidence from your data to support your answer.

 

5.      Draw a graph of balloon diameter vs. temperature. What is the correlation?

6.      Is there a negative control in this experiment? If yes, identify the control. If no, suggest how you could revise the experiment to include a negative control.

 

7.      In general, how would an increase in substrate alter enzyme activity? Draw a graph to illustrate this relationship.

8.      Design an experiment to determine the optimal temperature for enzyme function, complete with controls. Where would you find the enzymes for this experiment? What substrate would you use?

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