Writing Lab Report 1

1
Writing Lab Report 1

• Standard Curve Analysis for DNA Quantitation

2
Contents of Lab Report 1

• Cover Page
• Results
• Text
• Two Figures (graphs) with proper captions
• One Table with a proper caption
• Discussion
• For each figure and table provide a(n)
• Data Analysis
• Error Analysis
• Conclusion identifying the relationships observed
  in the data analysis

3
Cover Page

• Your name
• Names of your lab partners
• Lab Section
• Date

4
Results Text

• Briefly describe what each figure and table
  represents
• introduce the reader to the order in which you
  are presenting the data
• use an objective description that explains what
  you expect the reader to notice about the data
• do not interpret the data in this section
• do not provide error analysis
• You may briefly explain the pattern observed in
  the data and/or refer to the relationship
  indicated by the shape of each graph. Use the
  descriptions in the Lab Manual section How to
  Write a Scientific Report pages 11-12.

5
Results Figure 1

• Use Excel to plot the absorbance values at each
  concentration for YOUR GROUPS data
• Superimpose a smooth trendline
• Record the equation of the trendline to present
  in the caption and use in calculations for Table
  1
• Label the axes appropriately, indicating the x
  and y variables and their units of measure

6
Also for Figure 1

• Provide a caption below the figure
• title
• brief description, that can include
• source of the data
• relationship observed, including equation for
  trendline
• how the figure will be used in the results and/or
  discussion sections

7
Example of Figure 1 with Dr. Colavitos Data
Obtained in Summer 2010
8
Example of Figure 1 with Data Obtained in Summer
2010Adding a Trendline
Be sure to copy the trendline equation and save
it to use later.For the line on this grapy y
145.52x - 0.0793 R2 0.9849.
9
Example of Figure 1 with Data Obtained in Summer
2010Adding a Caption
I am the title of this PowerPoint slide, not the
title of the graph. Do not copy my format in your
lab report!
I am the description for this figure caption.
Yours will be more specific to the experiment you
performed, of course.
I am the title for this figure. Follow my format
but use your own words.
Figure 1 Standard Curve of Methylene Blue
Absorbance. Absorbance values were obtained for
dilutions of a 0.01 methylene blue solution. The
equation for the trendline is y 145.52x -
0.0793 R2 0.9849.
10
Results Figure 2

• For CLASS DATA, use Excel to plot the mean values
  for absorbance at each concentration
• Superimpose a smooth trendline(reporting the
  equation for this trendline is optional)
• Use the standard deviation values for Vertical
  (Y) error bars
• Label the axes appropriately, indicating the x
  and y variables and their units of measure
• Provide a caption below the figure

11
Example of Figure 2 with Data Obtained in Summer
2010
12
Example of Figure 2 with Data Obtained in Summer
2010Adding Error Bars
Each error bar shows the range of 1SD from the
mean value.
13
Results Table 1

• Determine the total yield of YOUR DNA EXTRACTION
  and show the process by providing the information
  for Columns 2-5 from Table 2 in the lab
  instructions
• Use any table format that clearly shows the
  results
• Showing the calculations is optional
• Provide a caption above the table

14
Data to present in Table 1(taken from Table 2 of
Lab Instructions)
2 3 4 5
Abs550 for Methylene Blue-stained DNA solution Concentration of Solution in (from standard curve) Concentration of DNA in micrograms/mL Total Amount of DNA Recovered(micrograms)

15
Using the Standard Curve in Figure 1 to determine
the percentage of methylene blue corresponding to
the DNA solution
Substitute 1.1 for the y value in the trendline
equation y 145.52x - 0.0793 x0.0081
16
Data to present in Table 1(taken from Table 2 of
Lab Instructions)
2 3 4 5
Abs550 for Methylene Blue-stained DNA solution Concentration of Solution in (from standard curve) Concentration of DNA in micrograms/mL Total Amount of DNA Recovered(micrograms)
1.1 0.0081
17
Discussion Data Analysis

• See Lab Manual Instructions for specific
  questions to consider in analyzing the data
• For Figure 1, state the line/curve shape that you
  proposed and then explain WHY the line/curve
  would be this shape. Be sure to consider the
  mathematical relationship illustrated by the
  line/curve shape. Your goal is to address the
  MECHANISM by which this relationship occurs.
• For Figure 2, discuss how well the data fit the
  proposed line/curve. Does the range shown by the
  data points error bars overlap the best fit
  line? If your data fit the proposed line/curve
  shape, TENTATIVELY accept the mechanism as an
  explanation for the observed relationship.

18
Discussion Data Analysis

• For Table 1, consider the usefulness of the
  standard curve in quantifying the DNA extracted
  from strawberries. Address the specificity of the
  protocol in isolating DNA. Discuss how you would
  determine if the DNA yield is reasonable.

19
Discussion Error Analysis

• Be BRIEF
• Suggest sources that match both the direction and
  magnitude of the error
• If deviation of data points from the curve or
  line is not large, do NOT suggest major sources
  of error.
• Consider systematic and intrinsic (random)
  sources of error
• One or two sources of error should suffice
• Indicate which sources of error are specific to
  each figure/table presented

20
Conclusion

• Write one (or a few) brief statement(s) that
  summarizes the relationship(s) observed between
  the variables that you studied
• Comment on the variation observed for the class
  data

21
Collaboration

• You may DISCUSS any aspects of your lab report
  with fellow students and/or your instructor
• You must PRODUCE the figures and WRITE your lab
  report independently
• Any unusual similarities will be addressed
  according to the SMC Code of Academic Conduct.
  Everyone involved will lose full credit for their
  reports. There are no makeups for lab reports
  showing academic dishonesty.