1. Quantitative analysis of biological samples.
Biology 201
Lab # 3
Medgar Evers College

2. Quantitative analysis is the use of numerical data to interpret a situation or outcome.
In biology, some form of statistical analysis must be performed on data before a valid conclusion can be reached!

3. Aim #1
Testing the accuracy of micropipettes using statistical analysis
Mean =average
Determine standard deviation= represents how much the values in each set vary from the mean.
You are pipetting 100 µl of water. You do it 5 times.
Example of data obtained; 100, 102, 102, 104, and 101 represents the age of five people in a town.
The mean = 101.8

4. Standard deviation equation

5. Standard deviation = square root of 1.76 = 1.32.
This would mean that as you were trying to pipette 100µl, the amount you were dispensing varied by 1.32 µl
Calculating the percent difference between the mean and standard deviation
% difference= standard deviation/mean x 100
1.32/101.8 x 100 = 1.29%

6. Spectrophotometry and generating a standard curve
Spectrophotometer- instrument used to measure light intensity as a function of wavelength and are used to measure the concentration of a substance in a solution
The more light absorbing molecules in a sample, the more light that will be absorbed.
As the concentration of the substance increases, there is a proportional increase in the light absorbed!

8. Aim # 2 Generate a standard curve using the lowry method
The lowry method for protein concentration determination is based on the formation of colored complexes.
The more intense the color the greater the concentration.
You will use saline to blank the machine, 25 µg/ml, 50µg/ml, and 100µg/ml standards to create your curve. You will determine an unknown value and plot your date.