LAB REPORT
The practical report involves performing a Bradford protein assay to calculate the total concentration of an unknown sample extracted by protein extraction, ‘method A’. The expected target yield for method A is 750 μg/mL.
Results
• It is recommended that you allocate 200 words to the results section.
• In the results section, you should provide a summary of the main results and present your main results in a logical order. Data analysis should be performed using Excel or SPSS. You should present the
following data in the results section:
• BSA standard curve with appropriate figure legend
- You should only plot data where the relationship is linear.
Table and table title to present the concentration of sample A/ the target value/ key statistical results.
- Remember to refer to the figure and table within the text and do not attempt to interpret the data in this section.
Discussion
• It is recommended that you allocate 300 words to the discussion
• You may use further subheadings to structure the discussion
• This is the section where you should interpret the data
- What have the results found in relation to the overall aim of the report stated in the introduction? Would you accept/reject the alternative/null hypotheses? Did the protein assay work? Is the quality of the data good? Critically assess the methods used - discuss potential sources of error in your laboratory work. What improvements could you make if this experiment were to be repeated in the future? What are the implications of the findings?
Reference list
• You should provide a reference list for all sources cited within the report
• Reference list should be provided as per APA 7th style.
Language/writing style
• Use a formal academic writing style and use scientific language throughout (APA formatting mandatory)
• The report should be written in the third person
• Write terms in full before using abbreviations
• Proofread your report before submission to avoid spelling, grammatical and punctuation errors.
You should submit a single file which is structured as follows:
• Results
• Discussion
• References
Strictly refrain from providing AI-generated and plagiarised solutions/nMethod
Preparation of 2 mg/mL BSA stock solution
In this first part, you will need to prepare 2mg/mL stock of BSA in DPBS (diluent) - you will need to prepare 10 mL of this stock solution. How much BSA will you need to weigh out using the analytical balance? Write any calculations in the space provided here:
1) Using the spatula and small weighing boat, weigh out the required volume of BSA powder
2) Transfer the BSA powder to a 15mL centrifuge tube. Label the tube '2mg/mL BSA solution' and label with your initials and the date
3) Pipette 10 mL DPBS into the 15mL centrifuge tube containing the BSA powder which you have weighed out
4) Mix by vortexing until all of the BSA powder has dissolved into solution
55
Preparation of standards (non-serial dilution)
Non-serial dilutions (V1C1=V2C2)
In this practical, the standards will be produced by performing non-serial dilutions. In non-serial dilutions, each standard is diluted from the stock solution. You will need to use the V1C1 = V2C2 equation to calculate how you are going to prepare the standards:
V x C = V. x C 2
V = volume of stock C = concentration of stock
V2 = volume of dilution (standard required)
C = concentration of dilution (standard required) 2
** Remember the units must be consistent on each side **
5) Prepare the following standards by diluting the BSA stock solution (2mg/mL) in DPBS:
· 2000 µg/mL
1500 µg/mL
· 1000 µg/mL
. 750 µg/mL
. 500 µg/mL
· 250 µg/mL
· 125 µg/mL
· 0 µg/mL
You will need to prepare a total volume of 500uL of each standard. Prepare the standards in 1.5 mL microcentrifuge tubes which you should clearly label with the relevant BSA concentration.
Record your calculations on the following pages.
56
Adding standards to a 96-welll plate
6) Add 5uL of each standard (0 - 2000 µg/mL) in triplicate to the 96-well plate as shown:
Note: ensure each standard is mixed before pipetting onto the plate Note: 5uL is a small volume and accurate pipetting is required, pipette the standard into the bottom of the well and make sure you keep track of which standards you have added.
1
2
3
4
5
6
7
8
9
10
11
12
A
2000
2000
2000
X
X
X
X
X
X
X
X
X
B
1500
1500
1500
X
X
X
X
X
X
X
X
X
C
1000
1000
1000
X
X
X
X
X
X
D
750
750
750
X
X
X
X
X
E
500
500
500
X
X
X
X
X
X
X
X
F
250
250
250
X
X
X
X
X
X
G
125
125
125
X
X
X
X
X
X
X
X
H
0
0
0
X
X
X
X
X
X
X
X
X
Adding the unknown sample 'A' to a 96-well plate
7) Add 5uL of the unknown sample 'A' in triplicate to the 96-well plate as shown: Note: ensure the sample is mixed before pipetting onto the plate
1
2
3
4
5
6
7
8
9
10
11
12
A
X
X
X
A
A
A
X
X
X
X
X
X
B
X
X
X
X
X
X
X
X
X
X
X
X
C
X
X
X
X
X
X
X
X
X
X
X
X
D
X
X
X
X
X
X
X
X
X
X
X
X
E
X
X
X
X
X
X
X
X
X
X
X
X
F
X
X
X
X
X
X
X
X
X
X
X
X
G
X
X
X
X
X
X
X
X
X
X
X
X
H
X
X
X
X
X
X
X
X
X
X
X
X
8) Using a single-channel pipette, pipette 200uL of the Coomassie protein assay reagent to each well containing standard or sample
9) Mix on the plate shaker for around 1 minute
10) Incubate the plate at room temperature for around 15 minutes
59
Measuring the absorbance values
11) Measure the absorbance of the plate at 620 nm using the plate reader
Stick your results onto this page.
1
2
3
4
5
6
A
1.2111
1.1195
1.1158 0.7756
0.7212
0.7444
B
1.1132
1.1056
1.1009
C
0.9843
0.8255
0.9666
D
0.7821
0.7777
0.7644
E 0.6592
0.6543
0.5273
F 0.4563
0.4422
0.4816
G
0.3981
0.3991
0.4022
H 0.3172
0.3224 0.3116
60
