Comparing Frog Gels:

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Comparing Frog Gels

• Analysis of Male and Female Samples

Jorge Bermudez Kathleen Cadman Nernie Tam
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Frog Gel Analysis

• The objective of the following analysis is to
  determine whether or not the sizes of extractable
  skin polypeptides vary with regard to the sex of
  the specimens.

Four samples were used--two 7.5 gels (one male,
one female), and two 12 gels (also male and
female).
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Methods Used

• Using Adobe Photoshop, we lined each individual
  sample up with a ruler and measured the distances
  between each polypeptide band.

• The bands were indicated by periodic darkening of
  the blue stain.
• Each measurement was recorded in a table using
  Microsoft Excel.

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Calculations
To extrapolate results from our data we
first needed to decide which model best
represented it.
Using Excel, we applied three standard models to
our male and female standards, and also to the
experimental data that best paralleled the
standards.
The standard models were
I. Linear (a bx)
II. Quadratic (a bx cx2)
III. Cubic (a bx cx2 dx3)
We also applied one non-standard model
IV. Non-standard (a bx c(ln(x))
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I. The Linear Model
When the linear model is applied, the accuracy
measurements for the 7.5 samples are as follows
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The accuracy measurements for the 12 samples are
as follows
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II. The Quadratic Model
When the quadratic model is applied, the accuracy
measurements for the 7.5 samples are as follows
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The accuracy measurements for the 12 samples are
as follows
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III. The Cubic Model
When the quadratic model is applied, the accuracy
measurements for the 7.5 samples are as follows
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The accuracy measurements for the 12 samples
were as follows
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IV. The Non-Standard Model
The 7.5 Samples
The 12 Samples
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Choosing a Model
Next we consider the order of the models. The
lowest is the most efficient.
In examing the applications of the various models
to our data, it becomes obvious that the cubic
model is the most efficient.
The cubic model, particularly when applied to the
7.5 samples, has the lowest ST-value, and
therefore the most precise margins of error.
Now that we have decided upon a model, we can
move on to comparing male and female samples.
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Analysis Male and Female Samples
Given the time constraints, our final analysis
of the data was somewhat more abbreviated
than our process for choosing a model.
We observed that there was a difference between
males and females with relation to the number of
extractable polypeptides more were extracted
from the female samples.
Again, given the time limit, we were unable to
determine whether the sizes of the
polypeptides varied according to sex. Had the
due-date been postponed, we would have actually
applied the model and obtained values for the
samples molecular weights.
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The 12 gel concentration produced better
results. With the higher concentration, the
polypeptides experienced less mobility, allowing
for greater visibility for the lighter stains
in the gel.
Because the 7.5 gel allowed the polypeptides
greater mobility, they tended to collect at the
bottoms near the dye fronts, making them harder
to differentiate.
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Error Analysis
(This is the part of the presentation where
we make excuses for our incompetence.)
Our calculations were probably the most
accurate part of the analysis. It is highly
probable that any errors resulted from the
initial collection of the data. Our estimations
of the relative mobility of the polypeptide
bands is--in all likelihood--riddled with human
error.
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In Conclusion...
For this particular analysis, the cubic model
was the most efficient.
When it comes to the number of extractable
polypeptides, female samples are superior.
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In Order of Appearance Nernie Tam Jorge
Bermudez Kathleen Cadman