# Open Excel on your computer=

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```					      How to GRAPH YOUR MALTOSE STANDARD CURVE (y = mx + b)
Open Excel on your computer = (Note this should work but if you have any trouble let me
know.)

1. Enter data series in two columns:
A: concentration x-axis
B: absorbance-y axis

2.   Highlight the data
3.   On the TOOLBAR look for the CHARTWIZARD icon (looks like a small bar chart)
4.   Check the XY SCATTERPLOT box
5.   Then choose one of the XY SCATTERPLOT types with lines
6.   Enter appropriate labels and titles
7.   FINISH the chart

Do 8 or 9 not both

8. Click on the line on the graph (with older versions of Excel this works)
9. or Click on the newly created chart window then on the CHART drop down menu and
from that list hit ADD TREND-LINE
Maltose Standards
Then                                                                   0.4
y = 0.1764x - 0.0031
0.35
R2 = 0.994
Absorbance (540nm)

10. Hit the OPTION tab on the dialog box and
0.3
Check both DISPLAY EQUATION and
0.25
DISPLAY R2 VALUE
0.2
0.15
0.1
0.05
0
0         0.4        0.8      1.2   1.6         2

Maltose (mg)

Standard curve of concentration versus absorbance

Plot data in Table 3.5 by placing mg of maltose (independent variable) on the x-axis
and absorbance (dependent variable) on the y-axis. Draw a line of best fit and
determine the equation of the line (y = mx +b; where m = slope of the line). Attach
your labeled graph to this sheet.

Table 3.5. Maltose Standards
absorbance        0        0.065      0.145       0.190                                     0.290         0.350
units
(540nm)
mg of          0         0.4         0.8                               1.2                 1.6          2
maltose

1
DATA CALCULATIONS & ANALYSIS USING EXCEL

1.        Use Maltose Standard Curve (Table 1) to Calculate Slope
Slope = rise = y = (y2-y1) = (0.35 – 0) = .175
run   x (x2-x1) (2.0 – 0)

2. Calculate AVERAGE ABSORBANCE:
Average = (value 1 + value 2) ÷ 2

Calculate the average of numbers in a row or column using Excel

1. Click a cell below or to the right of the numbers for which you want to find the average.
2. Click the arrow next to AutoSum         on the Standard toolbar (To display a toolbar,
press ALT and then SHIFT+F10.), and then click Average and press ENTER.

ALTERNATE METHOD FOR CALCULATING AN AVERAGE:

1.   Click a cell below or to the right of the numbers for which you want to find the average.
2.   Click on the fx button on the toolbar
3.   A “= sign” & a screen will appear asking you to select a function
4.   Select AVERAGE and then select the cell numbers you wish to average (C3 :C4)

3. Use Maltose Standard to Calculate Maltose (mg)
y = m (x) + b (this is the equation you will use to solve for x)
absorbance = slope (x) + y-intercept

absorbance = x
slope

AVE Absorbance = x
0.1764

How to divide numbers in a row or column using Excel

1. Click a cell below the AVERAGE ABSORBANCE VALUE you wish to divide by the slope.
2. Type the following formula into this cell: = CELL NUMBER/0.1764
3. For example, if you wish to divide the average absorbance in C5, type =C5/0.1764

2
NAME_________________________                     BIO 181-COTTER LAB

Temperature     4        23         37      65       100
A1             0.8       1.3        1.4     1.4       1.5
A2            0.845     1.27        1.4     1.5       1.6
AVG
maltose   x= absorbance/.1764

Temperature     4        23         37      65       100
B1             0.03     0.12       0.15    0.31      0.13
B2             0.1      0.14       0.21    0.41      0.17
AVG
maltose   x= absorbance/.1764

Temperature     4        23         37      65       100
C1              0        0.1       0.31    0.12      0.11
C2             0.03     0.27       0.53    0.08     0.112
AVG
maltose   x= absorbance/.1764

Determine the mg of maltose produced in each of the following conditions & record the
results in Tables 3.6. To calculate maltose (mg), use the average y-value
(absorbance) Plug y-value into the following equation and solve for x:
y = m(x) + b = slope of line (x) + 0

Table 3.6. Maltose Production as a Function of Temperature
Temperature      4C       23C       37C        65C    100C
A
Maltose (mg)
B
Maltose (mg)
C
Maltose (mg)

Create a graph showing the change in maltose production as a function of
temperature. Place temperature (independent variable) on the x-axis and mg of
maltose (dependent variable) on the y-axis. Attach your labeled graph to this sheet.

3
pH             5        6         7          8       9
A1            1.3       1.2       1.1        1.1     1.1
A2            1.45     1.45      1.35       1.35     1.3
AVG
maltose   x= absorbance/.1764

pH             5        6         7          8       9
B1            0.33      0.4      0.25        0.2    0.21
B2            0.35     0.35      0.18       0.15    0.18
AVG
maltose   x= absorbance/.1764

pH             5        6         7          8       9
C1            0.07     0.18      0.27       0.24    0.22
C2            0.07     0.12      0.175      0.162   0.072
AVG
maltose   x= absorbance/.1764

Determine the mg of maltose produced in each of the following conditions & record the
results in Tables 3.7.
To calculate maltose (mg), use the average y-value (absorbance)
Plug y-value into the following equation and solve for x:
y = m(x) + b = slope of line (x) + 0

Table 3.7. Maltose Production as a Function of pH
pH           pH5        pH6         pH7            pH8     pH9
A
Maltose (mg)
B
Maltose (mg)
C
Maltose (mg)

Create a graph showing the change in maltose production as a function of pH. Place
pH (independent variable) on the x-axis and mg of maltose (dependent variable) on
the y-axis. Attach your labeled graph to this sheet.

4

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 views: 4 posted: 11/5/2012 language: English pages: 4