Assignment #3 | BIOL 1P91 D2 ONLINE 2023
Assignment #3 – Fermentation
Overview
This exercise will be comprised of 3 parts: I) Critical Thinking & Application Questions; II) Methods
Section; III) Results Section.
Please complete Assignment #3 (counts as 5% of total Experiment #3 grade). All necessary
resources and documents can be found under Assignments > Assignment #3.
Research Question: Under which condition, aerobic or anaerobic, does optimal
Saccharomyces cerevisiae optimally produce ethanol?
Hypothesis: It is hypothesized that under anaerobic conditions ethanol
production will be optimal.
Part I: Critical Thinking & Application Questions (11 marks | 15%)
Copy and paste the questions below into a SEPARATE word document to answer. Include your methods
and results section AFTER the questions.
In order to answer the following questions, you will be required to research information. Remember to cite
any information obtained from additional sources. Be sure to use high quality (peer-reviewed sources,
NOT Wikipedia) Include a reference list at the end of the PART I.
1. What is biofuel? (2 marks)
2. What is Saccharomyces cerevisiae? Please describe. (2 marks)
3. Give an example of a dependent variable and independent variable from this experiment.
(2 marks)
4. In this simulation you were able to experiment by changing multiple variables at one time
(temperature, pH, airflow, and Stirrer%), why is it important to only change one variable at
a time? (1 mark)
5. Give an explanation as to why, under anaerobic conditions, ethanol concentration peaks
and does not continue to climb despite some surviving yeast cells. (1 mark)
6. Are there methods that allow yeast to tolerate high ethanol concentrations and therefore
produce more ethanol before dying? (3 marks)
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Assignment #3 | BIOL 1P91 D2 ONLINE 2023
Part II: Methods Section (40%)
A methods section is often overlooked as an essential component to any study, experiment, or primary
research article. A published study’s validity lies in the methods. Without knowing what materials,
equipment, procedures, etc. a researcher has used in their experiment it cannot be critiqued nor
repeated and thus has no validity.
Write a methods section describing the experiment you performed in the simulation. You have
been provided a detailed overview below of what a method section should contain. Please consult the
journal articles provided in the extra resources folder as examples of various methods sections.
Reference the simulation and lab outline for this section along with any other resource deemed
necessary; do not cite studies for comparison in this section.
Materials & Equipment List:
- Gloves
- Ethanol
- Saccharomyces cerevisiae cells in media suspension
- Inoculum injector
- Autoclaved culture media
- Glucose
- O2
- N2
- Fermentor (Labster simulations, Denmark)
- Acid in bottle
- Base in bottle
- Anti-foaming
- Waste collection bottle
- Media bottle
- Liquid pumps
Keys to the Methods Section (Adapted from Trent University, Academic Skills)
Purpose: How did you conduct this study?
Relative size: 10-15% of total
Scope: Narrow: the middle of the hourglass
Verb Tense: Always use the past tense when summarizing the methods of the experiment.
The methods section sets out important details.
The purpose of this section is to provide sufficient detail of your methodology so that a reader could repeat
your study and reproduce your results. Though the methods section is the most straightforward part of
the lab report, you may find it difficult to balance enough information with too much extraneous detail. To
test yourself, ask, “Would someone need to know this detail to reproduce this study?”
Avoid writing your methods as a step-by-step procedure; rather, present a concise summary of what you
did. Consider the following examples:
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Assignment #3 | BIOL 1P91 D2 ONLINE 2023
Example 1: “First, each group chose a turtle. A member of each group then measured the carapace
length, while another recorded the measurement in the lab book. A different group member then
recorded the turtle’s weight.”
Example 2: “Students determined carapace length (cm) and weight (g) for all individuals.”
The first example provides unnecessary information (the reader need not know that each turtle was
measured by a different group, nor which group member took the measurements) and is tedious to read.
The second is clear and concise, and it also provides the units of measurements. Note that it is not
necessary to mention that data were recorded – we assume that if you took the trouble to take a
measurement, you also wrote it down.
The methods section should contain information specific to your study only. This means that you generally
should not refer to other research and, therefore, should not include citations. Exceptions arise when
using another author’s method, such as when following the procedure from your lab manual, or when
using maps or diagrams from other sources.
Methods Section Details
Study area: Describe your study area. Geographic location, size, boundaries, topography, and habitat
type (forest or meadow composition, type of water bodies, for example) may be relevant.
Organism: If studying a particular organism, provide details of gender, age, and other relevant
information to your study.
Materials: Within the prose of your procedure text, integrate materials that you used. Include model
numbers of specialized lab equipment, concentrations of chemical solutions, and other such details.
Procedure: What you did – write in paragraph format (no point form or numbered steps). Include an
explanation of your experimental design, sample size, replicates, measurement techniques, etc.
Data Analysis: What statistical tests you used (including tests of normality), significance level set (α=?),
and any data manipulation required. Include specific calculations, if appropriate.
Figures: Include diagrams of study area, equipment, or procedures, where appropriate. Number and title
appropriately and refer to the figure within the text.
A good methods section should...
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Provide enough detail to allow an accurate reproduction of the study
Be written in a logically flowing paragraph format
Provide details on the study site, organism, materials, procedure, and statistical analysis
Should reference the lab manual, if appropriate
A good methods section should NOT...
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Be a recipe-book-style instruction guide
Provide a list of materials
Use bullet points
Cite other studies for comparison
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Assignment #3 | BIOL 1P91 D2 ONLINE 2023
Part II: Results Section (40%)
Write a results section that summarizes and describe the results of your experiment. Do NOT
include any additional tables or figures other than those described below. Also, do NOT show any rough
or sample calculations. You have been provided a detailed overview below of what a results section looks
like. Please consult the journal articles provided in the extra resources folder as examples of what results
sections look like. *Make sure to include a quantitative value for the maximum ethanol concentration
reached in each condition expressed as g/L.
i)
Create a figure(s) that depict the growth curves produced from both aerobic and anaerobic
conditions. Use the images below: (the images can be found in Experiemnt #3 folder)
a. Aerobic
b. Anaerobic
c. A figure title is located under the figure and has “Figure 1” in the title and not “Graph”.
i. The title should also be appropriately constructed; neither vague nor wordy. For
example; “CO2 versus Time” is not a fitting title. Don’t restate the y-axis heading
versus the x-axis heading in the figure title.
ii. Another example of a title to avoid is, “CO2 for the Fermentation Experiment”. This
title is vague and lacks description for the reader. Avoid being too wordy as well.
iii. If you find yourself writing a long, run-on sentence- that’s probably a good indication
your figure title is too wordy.
iv. Do not include units of measurement (like volume or time) in the title. The title is
placed below the graph itself.
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Assignment #3 | BIOL 1P91 D2 ONLINE 2023
d. Trends. Highlight the major trends or findings associated with the results of this
experiment. What should be noteworthy to the reader in terms of your experimental
results? Save proposing the possible reasons behind these trends (why things occurred
as they did) for the discussion section.
Regarding the trends, we’re concerned with how things occurred during the
experiment. Do this by providing a concise analysis of your experimental results
for the reader through observational statements backed up by numerical support.
Even though your data is presented in a figure and in table, point out to your reader
how the volume of CO2 produced by yeast change over time.
- Consider the following points (you’re not restricted to these and you’re encouraged
to add to this list): Was it slow at the start? Did it increase? When? By how much?
Do the same observations hold true of both (or all three) of your tested conditions
or were there differences? What are the differences? Avoid saying unsubstantiated
things like, “the values were close” or “the volume of CO2 was different”.
e. Instead, you could state a percentage or fold-difference. For example, if the mean
cumulative CO2 produced at the 30-minute mark for condition 1 was 2.5 mL and for
condition 2 it was 5.0 mL; then you could say, “After 30 minutes of fermentation, yeast in
condition 2 had produced 2-fold more CO2 than yeast in condition 1”.
While you do not have exact numerical values provided, infer from the graphs to describe phenomena
observed. For example, under aerobic conditions glucose levels were entirely depleted as ethanol levels
peaked at 23 hours. Ethanol production peaked at ___ g/L and ___ g/L under aerobic and anaerobic
conditions, respectively.
Keys to the Results Section (Adapted from Trent University, Academic Skills)
Purpose: What did you find?
Verb Tense: Always use the past tense when summarizing the results of your experiment
Summarize the results of your study.
Be careful to present your results in a manner that relates to your hypotheses; the reader should be able
to identify your hypotheses in your introduction and easily find their associated results. This is not a place
to provide raw data – present only summarized or analyzed data.
When appropriate, use figures and/or tables to present your results in a meaningful way and imbed them
within the text. Results should only be presented in one format though – either in the text, in a figure, or
in a table.
For example, if you are presenting means and standard deviations in a figure, rather than repeating
these same numbers in the text, refer to the per cent difference, increase, or decrease (e.g., Plant
height increased by 20% with the addition of fertilizer [Figure 2]). Do not explain what a graph is
showing (e.g., Figure 1 shows the mean +/- standard deviations of plant height in response to fertilizer
treatment) – the readers can see that for themselves.
Describe trends and patterns; highlight interesting and anomalous data; report significant findings. This
provides the reader with a more relevant context than would simple digits.
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Assignment #3 | BIOL 1P91 D2 ONLINE 2023
The results section should contain information specific to your study only. Therefore, it should not include
any interpretation of your results (this would require a comparison with other literature): do not state
whether your results supported or rejected your hypotheses; do not say what your results mean; and do
not compare your results to those of other studies.
Results Section Details
Description of results: You must include a written description of your results. Include only summarized
data (e.g., means, statistics, etc.) and point out trends, patterns, and interesting data. Refer to tables and
figures to support your descriptions.
Figures: Graphs provide a visual representation of your results. This is the ideal way to present your
findings. You must refer to each figure in the written portion of your results.
Tables: Use tables to present more complex or detailed results that do not lend themselves to figures or
text. You must refer to each table in the written portion of your results.
Appendix: This is an additional section, placed at the very end of your report after your reference section,
where you can include, if required, raw data and other supplementary information. You must refer to the
appendices in the written portion of your results.
A good results section should…
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Describe summarized data and statistical results
Describe trends and patterns; highlight interesting and anomalous data; report significant findings
Include appropriate tables and figures, referred to and imbedded within the text
A good results section should NOT…
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Include raw data
Repeat numbers from text, tables, and figures
Interpret or explain results
Refer to other studies
Format (5%)
Complete and format this assignment according to APA 7th edition. For formatting guidelines visit:
https://apastyle.apa.org/
1. Cover page
2. Part I (Include the questions and your answers)
3. Part II
• Methods section
• Results section
4. Reference List
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Include page numbers
12 pt. Times New Roman or Calibri
2.54 cm margins
Single spaced with headings where appropriate
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