Making Cheese

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Making Cheese

• Cheese-Making Lab is great for
• Showing how biotech has impacted
• an industry.
• Introducing scientific methodology (experimental
  design, data collection (data tables/graphs/data
  analysis, conclusions).
• Demonstrating the effects of too many variables.
• Introducing quantification, as with the
  whey-o-meter. _____ - o - meters can be used in
  many applications (juicing lab, protease activity
  lab, etc.)
• Getting students jazzed/focused the first day.

Ellyn Daugherty www.BiotechEd.com
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Cheese-making Procedure 1
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Cheese-making Procedure 2
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Cheese-making Procedure 3
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Cheese-making Procedure 4
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Improving Cheese-making

• Purpose
• Which curdling agent produces cheese the
  fastest?
• Which curdling agent produces the most cheese?
• To examine numerical data for support of
  predictions.
• To examine variables that can lead to invalid
  experiments.
• Hypothesis ______ is expected to produce the
  most volume of cheese in the shortest amount of
  time because it _________________________.

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• Procedures
• 1. Using a 10 mL pipet and pipet pump, transfer
  exactly 7 mL of whole milk into a labeled, 15 mL
  conical tube.
• 2. Using a pre-set micropipet, add 0.25 mL (250
  uL) of one of the four curdling agents to the 7
  mL of milk.
• Use either buttermilk, rennin, chymosin, or
  more whole milk (control) as assigned by your
  supervisor.
• 3. Cap the tube and gently mix by inverting 3
  times. Record this initial time. __________
• 4. Place the milk-containing portion of the tube
  deep in your armpit, like a thermometer, and
  incubate it there for at least 15 min.
• 5. Check for curdling every 5 minutes, recording
  the time to curdling in minutes. To check for
  curdling, gently tilt the tube, careful to not
  breakup any curds. Curds are large lumps of
  solidified milk. After 15 min, place the tube
  upright, at room temperature and check for
  curdling every 15 min for 2 hours. If curdling
  has not occurred within 2 hours, continue
  checking once every four hours. With the
  greatest accuracy possible, record the number of
  minutes passed until the milk had curdled to the
  greatest extent.
• 6. If curdling has not occurred by the end of
  the class period, bring the tube home (keep at
  room temperature) and back to class in 24 hours.
  Keep tube upright so any curds fall to the bottom
  of the tube.

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• Procedures
• 7. On return to the lab, measure the amount of
  curds (solids) and whey (liquid) in the tube.
  You may be able to read the volume of each
  directly off the tube although it may be
  difficult. Better yet, filter it as described
  below, using a whey-o-meter.
• 8. If necessary, pour the whey and curds mixture
  through a filter paper funnel into a 10 mL
  graduated cylinder (a whey-o-meter). Determine
  the volume of whey collected in the graduated
  cylinder, using a pipet if necessary to measure
  small amounts. By subtraction, determine the
  volume of curds. Can you suggest other methods
  of determining the amount of curds produced in
  each treatment?
• 9. Record the data for your sample plus one each
  of the other variable groups on the data table
  below. Record the name of the person from whom
  you have gotten data.

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Fill in the Blank-o-Meter

• Fill in the Blank-o-Meter

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• Using Excel, the lab supervisor will collect
  each individuals data to make a class data table
  showing multiple replications of the experiment.
  Averages for each variable group should also be
  recorded on this data table. Averaged data is
  the best answer to an experimental question. Can
  you explain why?
• 11. Using Excel, produce two graphs one which
  shows the average time to curdling for each
  enzyme treatment and one which shows the average
  volume of curds produced by each enzyme
  treatment. Use the Excel tutorial if necessary.

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• Imagine you are an employee at a cheese curdling
  company and you must summarize the results of
  your experiments and give your supervisor the
  best answer to the scientific questions asked.
  Write a conclusion that reports the Results of
  the experiment (answer to the purpose question)
  including Evidence and Explanations for your
  findings. Discuss how well the results support
  the hypothesis. Identify sources of Possible
  Errors in the technique that may lead to
  variations in results (see next slide). Think
  about the Practical Applications of the results
  of the experiment. Make a recommendation to the
  cheese company supervisor about which curdling
  agent should continue to be the focus of
  production. Include any variations in the
  procedures that you think may improve the cheese
  production.
• 13. In the biotechnology industry, the work of
  others is reviewed and OKd by peers. This is
  called witnessing. When you witness data and
  analysis, check for
• Accuracy of statements (and that they make sense)
• Completeness (R/E/E, PE, PA)
• Evidence (numerical with units of measurement)
• Grammatical and spelling errors
• Make correction and suggestions right on the
  page,
• For corrections, strike a single line through the
  error, correct it, and initial it.
• For suggestions, write your suggestion in the
  margin, draw an arrow where it should be placed
  and initial it.

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Animal Use Bioethics

• Rennin is a product that requires sacrificing an
  animal.
• Each person develops a position on what they will
  support in terms of animal use.
• A team of students develops a public policy on
  the use of animals at an institution.

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BiotechnologyScience for the New Millenium
Textbook with Encore CD ISBN 0-7638-2282-5
Chapter 1 Bioethics Laboratory Manual ISBN
0-7638-2285-X Lab 1c Textbook with Encore CD
and Lab Manual ISBN 0-7638-2278-7 Text with
Encore CD and Lab Manual and Lab Notebook
0-7638-2279-5
http//www.emcp.com/biotech
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