Environmental Science

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Date:

Instructor’s Name:

Assignment: SCIE211 Phase 3 Lab Report

Title: Sources of CO2 Emissions

Instructions: You will need to write a 1-page lab report using the scientific method centered on the known phenomena of CO2 emissions, related to the following question:

· Would you expect to see an increase or decrease in CO2 emission in the data over the past 40 years? Why?

When your lab report is complete, post it in Submitted Assignment files.

Part I: In the Web site link given in the assignment description, you will see an interactive map of the world titled “GMD Measurement Locations.” You can zoom in and out and move the map around within the window. In the map, choose 5 sites that are labeled with a star, which will have CO2 concentrations. Follow the steps below to fill in the data table:

1. Click on a starred location. (One site will not have CO2 concentrations.)

2. Once the starred location opens, on the right side of the screen, click on the pictured graph “Examples of Data” for CO2.

3. Once the graph opens, make a note of the CO2 concentrations from previous years to present day. Fill in the table below.

4. Repeat steps 1–3 for all other locations.

5. Use these results in your lab report to help you assess CO2 concentration trends from 1990 to 2005.

Location Code Name of City/Country CO2 Emissions in 1990 CO2 Emissions in 2005
       
       
       
       
       

Part II: Write a 1-page lab report using the following scientific method sections:

· Purpose

· State the purpose of the lab.

· Introduction

· This is an investigation of what is currently known about the question being asked. Use background information from credible references to write a short summary about concepts in the lab. List and cite references in APA style.

· Hypothesis/Predicted Outcome

· A hypothesis is an educated guess. Based on what you have learned and written about in the Introduction, state what you expect to be the results of the lab procedures.

· Methods

· Summarize the procedures that you used in the lab. The Methods section should also state clearly how data (numbers) were collected during the lab; this will be reported in the Results/Outcome section.

· Results/Outcome

· Provide here any results or data that were generated while doing the lab procedure.

· Discussion/Analysis

· In this section, state clearly whether you obtained the expected results, and if the outcome was as expected.

· Note: You can use the lab data to help you discuss the results and what you learned.

Provide references in APA format. This includes a reference list and in-text citations for references used in the Introduction section.

Give your paper a title and number, and identify each section as specified above. Although the hypothesis will be a 1-sentence answer, the other sections will need to be paragraphs to adequately explain your experiment.

When your lab report is complete, post it in Submitted Assignment files.

 
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Mendelian Genetics Lab

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Background

The laws of segregation, independent assortment, and dominance, discovered in the mid 19th century by Gregor Mendel, form the basis of all genetics. The ability to predict the results of crossing experiments and explain any variance between expected and observed results is still a vital part of our understanding of heredity. The relationship between the genotype and the phenotype of an organism is now understood with better clarity than it was in the early part of the 20th century. Today our ability to determine gene sequences in individual organisms and populations of organisms has allowed us to deepen our understanding of heredity. In this lab assignment you will experiment with monohybrid crosses and explore the role of chance in genetics.

 

 

I have already started the lab work

Lab Template

Week 5: Mendelian Genetics

 

Submitted by: <your name here>

 

As you complete the lab, record your answers in this template. Save the document as LastName_FirstName_BIO1020_W5A3, and submit it to the Dropbox. Full lab instructions and the rubric with which you will be evaluated can be found in the online classroom.

 

Activity

The laws of segregation, independent assortment, and dominance form the basis of all genetics. The ability to predict the results of crossing experiments and explain any variance between expected and observed results is still a vital part of our understanding of heredity. In this lab assignment you will experiment with monohybrid crosses and explore the role of chance in genetics.

 

 

Experiment 1

Questions

1. (10 points)

a. Set up and complete Punnett squares for each of the following crosses: (remember Y = yellow and y = blue)

 

· Y Y and Y y

 

    Parent 1
    Y Y
Parent 2 Y YY YY
  y Yy yy

 

 

 

 

 

· Y Y and y y

    Parent 1
    Y Y
Parent 2 Y Yy Yy
  y Yy Yy

 

 

 

 

 

b. What are the resulting phenotypes for each cross? Are there any blue kernels?

Y Y and Y y Y Y and y y
 

The resulting phenotypes is that all the offsprings are yellow because all the offspring have at least one Y (yellow, dominant) allele

 

 

 

 

  

All the offsprings are yellow

There are no blue kernels in either cross and all are yellow because the genotypes of all the kernels have at least one dominant (Y) gene which codes for yellow color.

 

 

2. (10 points)

a. Set up and complete a Punnett squarefor a cross of two of the F1 from the Y Y and y y cross above.

 

 

 

     

Parent 1
    Y Y
Parent 2 y Yy Yy
  y Yy Yy

 

 

 

 

b. What are the genotypes and phenotypes of the F2 generation?

 

 

The genotypes of offsprings are Yy (heterozygous) and their proportion is 100% If Y= yellow an y= blue, then the phenotypes of the off springs would be the characteristics of Y gene which means all the off springs will have a yellow color.

 

 

 

 

 

 

Experiment 2

Questions

As you select the beads from the beaker, complete this table with each cross. You may complete the associated Punnett Squares on paper, but do not need to submit them as part of this lab.

 

  Parents – randomly selected F1 – determined from Punnett square
Cross Genotype parent #1 Genotype parent #2 4 Genotypes 4 Phenotypes
1 yy

 

 yy yy yy
2  

Yy

 yY YY Yy
3  

Yy

 YY YY YY
4 yY

 

 yy Yy yy
5  

yy

 YY Yy Yy

 

 

1. (10 points)

a. How much genotypic variation do you find in the randomly picked parents of your crosses? How much in the offspring?

 

 

Possible Genotype Parents Offspring
YY 3 4
Yy 3 10
yy 4 6
Total 10 20

 

 

 

 

 

b. How much phenotypic variation do you find in the parents of your crosses? How much in the offspring?

 

 

 

 

 

2. (10 points)

a. What is the ratio of phenotypes (yellow kernel color: blue kernel color) in the 20 offspring of your five crosses?

 

 

 

 

 

b. If you were to run this experiment 1000 times, rather than just 5 times, what would you expect the ratio of phenotypes to be in the offspring?

 

 

 

 

 

c. Is the ratio of observed phenotypes the same as the ratio of predicted phenotypes in the offspring? Why or why not?

 

 

 

 

 

 

 

 

3. Organisms heterozygous for a recessive trait are often called carriers of that trait. Explain what this means. (10 points)

 
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Procurement And Administration

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 Built Environment

BSc Architectural Design & Technology BSc Building Surveying
BSc Construction Project Management BSc Quantity Surveying

Procurement and Administration
Coursework
Submission Deadline: Friday 24th April 16:00hrs
This assessment contributes 50% of the marks for the above module. 4000 word limit

1. BRIEF

1.1 About You

You are employed by the GMSA as independent construction procurement professional for this project.

1.2 Background

The Greater Manchester Strategic Alliance (GMSA) is a partnership of universities, colleges, work based learning providers and other stakeholders who collectively deliver a Lifelong Learning Network (LLN) and promotes the progression of vocational learners into Higher Education. GMSA have identified within their strategic plan for 2014 – 2019, the opportunities presented by recent government commitment to fund a significant increase in the delivery of Higher Apprenticeships. As a result, GMSA are consulting on the viability of a new “Advanced Manufacturing Research Centre” situated alongside the M62 Corridor in Greater Manchester. The centre will draw on the specialist skills of both the four Greater Manchester universities together with a series of local colleges

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including those in Rochdale, Oldham and Bury together with leading business organisations located in the Greater Manchester area.

Important features of the development to note:

  •   10 storey, 30,000m2 main building including 3 250 seat lecture theatres,

    30 seminar rooms, a central catering facility, Coffee shop styled area,

    office accommodation and student support areas.

  •   2 storey, 5.000m2 ‘advanced engineering’ centre, providing specialist

    engineering laboratory and workshop facilities.

  •   4 Storey, 8,000m2 central learning centre, providing student services

    including open access rooms, silent study areas, group study rooms and a

    library facility

  •   External works including infrastructure development.

    The Client requires the building to be carbon neutral. In addition, to illustrate both aspirations of both Central Government and the GMSA the facility should make a clear architectural statement and must be constructed to the highest aesthetic and qualitative standards. Value for money given the current economic climate is also a key consideration.

    The budget to cover the total development cost, inclusive of construction works, external works, statutory and professional fees is estimated to be £71 million. The completion date is critical, as the building requires handover by August 2017 at the very latest, to accommodate the new academic year.

    Title to the land is currently under negotiation. As the scheme forms part of the ‘Northern Power House’ vision, public funding (provided by the Department of Education) has been approved. Who will operate the facility on completion is yet to be decided.

    1.3 Assessment Requirements

    Task 1 (word limit 3000):

    GMSA have commissioned you to recommend the most appropriate procurement strategy to meet their requirements. They have requested that you produce a report of no more than 3000 words which provides an analysis of the key procurement issues for the organisation to consider. The report should be addressed to this client and it must provide a clear recommendation for the most appropriate procurement strategy and system to meet their requirements.

    While value for money is a key consideration given the current economic client, GMSA is also eager to embed both socio-economic and environment sustainability within their project. They are particularly concerned with the consequences of the Public Services (Social Value) Act 2012.

    You should make a justified recommendation for an appropriate procurement strategy, detailing the advantages and disadvantages for the Client of your preferred procurement strategy and system.

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It is also a requirement to identify a suitable main form of contract to match the procurement strategy and to enable the University to realise their strategic objectives.

Task 2 (word limit 1,000):

The GMSA is eager to embed both socio-economic and environment sustainability within their project. In no more than 1,000 words, as part of the same report, explain how your procurement strategy helps them to embed socio-economic sustainability into the procurement decision-making and outcomes of the project.

2. SUBMISSION REQUIREMENTS

FORMAT

All submissions should have a cover sheet identifying the module, the date and the student’s name and roll number. In addition to the in-text citations, all submissions shall have a reference list (and an optional bibliography), listing the sources used in the preparation of the report. [The School has adopted the Harvard system (APA 6th) as standard

LENGTH

Maximum 4,000 words report excluding references, bibliography, cover sheet or appendices (if any).

SUBMISSION

This assignment MUST be submitted electronically through Turnitin®
Further information and support for students using Turnitin can be found here:

http://www.salford.ac.uk/library/help/blackboard-and-collaborate

3. ASSESSMENT CRITERIA

Item

Marks

The report should provide a critical analysis of the Client 30 requirements and evaluation of appropriate parameters.

Appraisal of alternative procurement strategies and 35 systems with a justification for your recommended
strategy and system

Identifies the drivers for the client requirements for socio- 25 economic sustainability and how they can be delivered
through the project – reference to the Public Services
(Social Value Act) 2012 is necessary.

Presentation of information required for each task 10

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4. MARKING SCALE

At Undergraduate Level 4, 5 and 6 the following marking scale shall be used:

Outstanding Excellent Very good Good

Fair
Adequate Unsatisfactory Poor
Very poor Extremely poor

90% – 100% 80% – 89% 70% – 79% 60% – 69% 50% – 59% 40% – 49% 30% – 39% 20% – 29% 10% – 19%

0% – 9%

5. LEARNING OUTCOMES ADDRESSED

Critically evaluate client objectives and determine the appropriate selection of procurement systems

Analyse project objectives under time, cost and quality, sustainability issues Use techniques such as procurement matrices to assist in decision making Develop an understanding regarding the selection of appropriate contract forms Appreciate issues and implications in connection with contractor selection Develop skills in report writing

Develop skills in procurement research

6. RETURN & FEEDBACK ARRANGEMENTS

Coursework marks and feedback will be available within 15 working days of your submission and will be loaded into Blackboard.

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IMPORTANT INFORMATION I. OBLIGATION TO KEEP COPIES OF ALL WORK

Students MUST keep a spare copy of all work which they hand in as well as the receipt which is issued to them at the time of submission.

II. PROVISIONAL NATURE OF MARKS & GRADES

All marks and grades issued to students are provisional until ratified by examination boards.

III. LAST DATE FOR SUBMISSIONS

Submissions made after 16:00hrs on the fourth working day following submission will be deemed inadmissible and recorded as a non-submission.

IV. ELECTRONIC SUBMISSIONS

If the submission document file up-loaded to Blackboard is corrupt and cannot be viewed – This is classed as a NON submission. It is the responsibility of the student to ensure their submission material can be opened by others.

To ensure your submission can be opened please follow this simple step:

Go back to the submission area and the blue button that was labelled Submit will now be a button labelled View – select this button and what you see upon doing so will be the file/format that your Lecturer can see. If you can open and view the document then so can the lecturer.

V. PENALTIES FOR LATE SUBMISSION

Where coursework is submitted late, the following penalties shall be applied to the mark:

(a) if the work is no more than four working days late, then five marks shall be deducted for each working day (08:30-16:00 Mon- Thursday or part thereof) , but if the work would otherwise pass then the mark for the work shall be reduced to no lower than the pass mark for the component

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(b) if the work is no more than four working days late and marked and the mark is lower than the pass mark, then no penalty shall be applied;

(c) if the work is more than four working days late then it cannot be submitted and shall be recorded as a non-submission (NS).

VI. ACADEMIC MISCONDUCT

The University takes a serious view of all acts of academic misconduct. Such acts are considered dishonest and as attempts to gain unfair advantage. Acts of academic misconduct can take many forms. They are likely to fall into one or more of the following categories:

  1. a)  Plagiarism
    Plagiarism involves taking the work of another person or source and using it as if it were one’s own.
  2. b)  Self plagiarism
    Self plagiarism (or double submission) is resubmitting previously submitted work on one or more occasions (without proper acknowledgement). This may take the form of copying either the whole piece of work or part of it. Normally credit will already have been given for this work.
  3. c)  Collusion
    Collusion occurs when, unless with official approval (e.g. in the case of group projects), two or more students consciously collaborate in the preparation and production of work which is ultimately submitted by each in an identical, or substantially similar, form and/or is represented by each to be the product of his or her individual efforts. Collusion also occurs where there is unauthorised co-operation between a student and another person in the preparation and production of work which is presented
    as the student’s own.
  4. d)  Falsifying experimental or other investigative results
    This could involve a range of things that make it appear that information has been collected by scientific investigation, the compilation of questionnaire results etc whereas in reality it has been made up or altered to provide a more favourable result.
  5. e)  Taking unauthorised material (including electronic devices) into an examination
  6. f)  Contracting another to write a piece of assessed work / Writing a piece of assessed work for another
    This involves any means whereby a person does work on behalf of another. It includes assessments done for someone else in full or in part by a fellow student, a friend or family member. It includes sitting an

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g) h)

VII.

a)

examination for someone else. It also covers obtaining material from internet ‘cheat sites’ or other sources of work. Penalties for this type of unfair means will normally apply both to a student of the University who does work on behalf of another and a student of the University who has work done for him/her.

Copying from, or communicating with, another examination candidate during an examination

Bribery
This involves giving money, gifts or any other advantage to an academic member of staff which is intended to give an unfair advantage in an assessment exercise.

Particular care should be taken in respect of the following:

Getting help from others / helping others

Students are encouraged to discuss and share ideas and information, however those who knowingly assist others to commit academic misconduct whether or not for payment (e.g. by giving another student the opportunity to copy part or all of a piece of work, by providing copies of assessments or by providing bespoke assignments to another student) will be subject to the same penalties as those who use unfair means. Students must ensure that they protect their own work, submit it themselves and do not allow other students to use their memory stick and/or print off work on their behalf.

b) Use of Readers/Note Takers

Students with special learning requirements who require the services of readers or note takers are advised to use appropriately trained individuals. Further advice can be obtained from the Disability Service Team within Student Life Directorate. http://www.advice.salford.ac.uk/disability

c) Referencing

Students using work which has been produced by other people within an assignment will need to ensure that they acknowledge or reference the source of the work. Students should check with their Schools for particular requirements. Marks may be deducted for poor referencing. If poor referencing is extensive throughout a piece of work it could appear that the student is trying to claim credit for the work and he/she may be deemed to have committed plagiarism. Guidance on good referencing practice is available from Schools or may be provided through research training programmes, the Study Skills Programme located in Student Life and on-line guidance provided by Information & Learning Services. Some useful resources are: http://www.advice.salford.ac.uk/

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Penalties

If satisfied that unfair means has occurred, a penalty will be imposed on the student. Penalties vary depending on whether the matter is referred to the School Academic Misconduct Panel or the University Disciplinary Committee and on the particular circumstances. A range of penalties may be imposed including:

  • –  A penalty of 0% for the assessment component attempted using unfair means;
  • –  A penalty of 0% for the module affected by unfair means;
  • –  A penalty of 0% for the module affected by unfair means and the marks of all other modules at that academic level being capped at the pass mark

    (40% for undergraduates, 50% for post graduates).

    In the most severe cases, where there are aggravating factors (e.g. that this is a repeated case of the use of unfair means by a student at an advanced stage in their studies), a student found guilty of using unfair means may be permanently expelled from the University.

    Further details of the Academic Misconduct procedure are available from:

    http://www.governance.salford.ac.uk/page/student_policies

    Pre-submission checklist

    Before submitting your assessment; ask yourself the following questions, just to be sure you’ve met all the requirements:

  •   Have I correctly referenced all the sources which I have used?
  •   Have I used Turnitin to check my referencing and bibliography so that my

    tutor knows where I have found all my information?

  •   Have I completed the assignment within the word limit and/or stated my

    word count?

  •   Have I used a spell checker and proof read my work?

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Lab 4: Enzymes

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1

 

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?

 

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

 

3. 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.

5. 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.

6. Select two food items from your kitchen cabinet or refrigerator.

7. 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.

8. 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).

9. Wash your hands with soap and water.

10. 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.

11. Wait five minutes.

12. Hold the IKI spray bottle 25 – 30 cm away from the paper towel, and mist with the IKI solution.

13. 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:

a. 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).

b. 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.

c. If using a stove, place a small pot on the stove and turn the stove on to a medium heat setting.

d. 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.

e. 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.

6. 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.

7. Let the tubes sit for 15 minutes.

8. During the 15 minutes prepare the balloons with yeast by adding ¼ 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.

9. Carefully stretch the neck of the balloon to help ensure it does not rip when stretched over the opening of the test tube.

10. 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.

11. 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.

12. 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.

13. Swirl each tube to mix, and wait 30 seconds.

14. 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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