Biochem post lab 4- Google Docs PDF

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Centennial College, Morningside Campus Session 2021

Biochemistry CH 222

Lab Experimental Report #4 Isolation and identification of DNA

Submitted by: Manbir kaur (301091180) Ridhi gaglani(301172317) Dwira thacker(301123309)

june 9, 2021 Table of Content 2. Data tables Table 2.1 Diphenylamine test for the presence of deoxyribose Table 2.2 Molybdate tests for the presence of phosphate Table 2.3 Test for purine bases 4. Post lab

Results

Table 2.1 Diphenylamine test for the presence of deoxyribose Test tube

Solution

Results

Conclusion (does this

1.

Lab dna

Turned yellowish- white

yellowish white color indicates absence of deoxyribose in the solutio which is unexpected result.

2.

Commercial DNA

Turned light brown

the solution turned light brown in color indicating the presence of deoxyribose

3.

Ribose

Turned light grey

the solution turned light grey in color indicating the absence of deoxyribose

4.

Deoxyribose

Turned dark brownish

the solution turned dark brownish in color indicating the presence of deoxyribose

5.

Commercial RNA

Turned chocolate (light) brown

the solution turned chocolate brown in color indicating the presence of deoxyribose

6.

Distilled Water

Turned yellowish- white

yellowish white color indicates absence of deoxyribose in the solution

contain deoxyribose?)

Table 2.2 Molybdate tests for the presence of phosphate

Test tube

Solution

1.

Lab dna

Turned light green

2.

Commercial DNA

Turned green blue

3.

Ribose

results

Transparent white

4.

5.

6.

Na 3PO4

Turned dark blue

Commercial RNA

Turned green bluish

Distilled Water

Transparent white

Conclusion (does this contain PO4 -3 ?) the light green color of solution indicates the presence of phosphate in solution the green- blue color of solution indicates presence of phosphate in solution the white of solution indicates absence of phosphate in solution the dark blue color of solution indicates presence of phosphate in solution the greenish blue color of solution indicates presence of phosphate in solution the white color of solution

(light) indicates absence of phosphate in solution

Table 2.3 Test for purine bases Test tube

Solution

Results

Conclusion (are purine bases

present?)

1.

2.

Lab dna hydrolysed

Commercial DNA

Transparent liquid, white ppt performed

a white colored precipitate has been formed at bottom of test tube it means purine based is present.

Transparent liquid, white ppt performed

a white colored precipitate has been formed at bottom of test tube which confirm the presence of purine

a white colored precipitate has not been formed in test tube it means absence of purine

(hydrolysed)

3.

Ribose

liquid turned blackish

4.

Adenine

solidified, turbid white, brown ppt performed

5.

Commercial RNA

Transparent liquid

(hydrolysed)

6.

Distilled Water

Black colour

a brown colored precipitate has been formed in test tube which means absence of purine No precipitate has been formed at bottom of test tube which means absence of purine;

No precipitate has been formed at bottom of test tube

Post lab questions:-

1. Draw the structure of the major purine and pyrimidine bases that are part of the DNA

2. Draw the structures of ribose and deoxyribose. Answer: Ribose and deoxyribose structure:

5. It is important that you understand the steps in the extraction procedure and why each step was necessary. Each step in the procedure aided in isolation the DNA form other cellular materials. Match the procedure with its function:

PROCEDURE FUNCTION

A. Filter pea slurry through cheesecloth - To separate components of the cell

B. Mush pea with Solution 1 and 2 - To break up proteins and dissolve cell membranes

C. Initial smashing and grinding of pea -

D. Addition of ethanol to filtered extract

To break open the cells

-To precipitate DNA from solution

Question 6-Why is it important for scientists to be able to remove DNA from an organism? List two reasons.

It is important for scientists to be able to remove DNA from an organism because the fact of the structure of the organism is hard to understand just by hearing it, you have to visually see the DNA to understand its concepts. The scientists have

to be careful when trying to extract it, they don’t want to break or ruin the DNA...