Biochemistry Lab Report
Essay by Yan Xin • November 26, 2015 • Term Paper • 423 Words (2 Pages) • 1,889 Views
Result:
Table of absorbance reading at 510 nm with different volume of banana extract and 3ml of DNS reagent
Test tube | Volume of banana extract (ml) | Absorbance reading at 510 nm |
A | 1 | 2.207 |
B | 2 | 2.302 |
Table of absorbance reading at 510 nm with different glucose concentration and 3ml of DNS reagent
Tube no. | Concentration of glucose (mg/ml) | Absorbance reading at 510 nm |
1 | 0 | 0 |
2 | 0.25 | 1.052 |
3 | 0.5 | 1.721 |
4 | 1 | 2.181 |
5 | 2 | 2.270 |
6 | 5 | 2.336 |
7 | 10 | 2.371 |
[pic 1]
Figure of the absorbance at 510 nm against the concentration of glucose(mg/ml)
Calculation
To calculate the amount of glucose in the banana sample, we need to add the two absorbance readings obtained then average it, that is
(2.207+2.302)÷2=2.25
By plotting the value of 2.2545 in the standard curve, we found out the concentration of glucose present in the banana sample is 1.3 (mg/ml).
Question
- Why Rochelle salt solution required to be added in while the test tubes still warm?
- Why the test tube need to be cooled to room temperature before absorbance reading is to be taken?
This is because we need to wait the stabilization process of the colour formed is fully completed and stable as the colour intensity will affect the absorbance reading.
- Why it is necessary to neutralize the sample to pH 7.0?
Discussion
In this experiment, we used the Dinitrosalicylic Acid method to estimate the amount of glucose in the banana sample. We need to prepare a Glucose Standard curve to determine the amount of glucose present in the banana sample.
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