biology lab report protein.docx

8/11/2019 Biology lab report protein.docx

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INTERNATIONAL BACCALAUREATE ORGANIZATION

Diploma Program

San Ignacio de Recalde School

Lab Report

Protein quantification

Candidates Name:Arturo Valdez Aguilar

BiologyStandard Level

Diploma Session: November 2012

LIMAPERU


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1. Introduction

Albumin is proteins made by the liver and measure the concentration in

solution. In this experiment, we will work with albumin and determine the

concentration of an unknown sample.

2. Research question

Can we determine the concentration of albumin in an unknown sample

(codorniz egg), by using a standard curve?

3. Hypothesis

By using a standard curve, we will determine the concentration of the problem

sample.

4. Variables

Dependent

Absorbance

Independent

Concentration

Controlled

Water

Albumin

Biuret

5. Materials and method

7 ml albumin (6.09 g/dl)

8ml Biuret reagent

4 test tubes in a rack

1 pipette 10ml

1 pipette 1ml

1 pro-pipette

Distilled water

Spectrophotometer UV/VIS light

Spectrophotometer cubettes


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First the Biuret was added in 4 test tubes with 1 ml, the color was light

blue.

Then, in the last 3 test tubes, we added Albumin with water. The color

was purple.

We record the data in a piece of paper.

6. Data gathering

Pipette used for albumin: 0.01

Pipette used for water and Biuret: 0.5

Using the spectrophotometer, we got this data (Absorbance):

(The blank test tube is not shown, we didnt need it)

Table n : Absorbances

(0,0005)

Tube 1 Tube 2 Tube 3 Unknown

(codorniz egg)

0.543 A 0.493 A 0.431 A 0.38 A

7. Data analysis

With the absorbance data, using the formula c1v1=c2v2,

we found theconcentrations.

Table n 2: Concentrations

Tube 1 Tube 2 Tube 3

6.09 g/dl 3.045 g/dl 4.06 g/dl

But we still need to find the concentration of the unknown sample.


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To do so, we will use this equation: Absorbance/ Concentration = Absorbance / X

(X being the unknown sample).

And we will have the concentration of the unknown sample: 3.580

Table n 3: Standard curve chart

The x values (horizontal line) show the concentration and the y values (vertical

lines) show the absorbance.

8. Conclusion and evaluation

We managed to determine the concentration of an unknown sample and

represent it on the standard curve line.

Some limitations can be that there was only one unknown sample so we cannot

assure that our results from the unknown sample were correct.

A suggestion for the experiment is that we could try using different dilutions of

water and albumin so we can observe the variation in concentration and

absorbance between the various samples and see if there is a relation.

0

0.1

0.2

0.3

0.4

0.5

0.6

0 1 2 3 4 5 6 7

Absorbances(A)

Concentrations(g/dl)


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9. Bibliography

http://www.ruf.rice.edu/~bioslabs/methods/protein/spectrophotometer.html

http://chemistry.about.com/od/lecturenotesl3/a/concentration.htm
http://www.ruf.rice.edu/~bioslabs/methods/protein/spectrophotometer.htmlhttp://www.ruf.rice.edu/~bioslabs/methods/protein/spectrophotometer.htmlhttp://chemistry.about.com/od/lecturenotesl3/a/concentration.htmhttp://chemistry.about.com/od/lecturenotesl3/a/concentration.htmhttp://chemistry.about.com/od/lecturenotesl3/a/concentration.htmhttp://www.ruf.rice.edu/~bioslabs/methods/protein/spectrophotometer.html

biology lab report protein.docx

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