Important Talent Search Exams

Allen TALLENTEX 2018 (Class 5 to 11)
Aakash ANTHE 2017 : 100% Scholarship (Class 8, 9, 10)

BIOTECHNOLOGY

Paper 2 (Practical)

(Three hours)

 (Candidates are allowed additional 15 minutes for only reading the paper.

They must NOT start writing during this time.)

 ………………………………………………………………………………………………………………………………….

 This paper comprises two sections – Section A and Section B.

Answer Questions I (compulsory) anti any two other questions from Section A.

Section B is compulsory.

The intended rnarks for questions or parts of questions are given in brackets [ ].

 ………………… ~ ……………………………………………………………………………………………………..

 SECTION A

Question I (Compulsory)~

(a) You are given two solution S~ and S2. Take three test tubes and label them as A, B and C. Dispense 2 ml of the solution S~ into each of the three test tubes A, B and C.

Proceed as follows:

To test tube A, add two drops of iodine solution. Shake the contents of the test  tube well. Note the colour change.

To each of the test tubes B and C, add 2 mi of solution S2. Keep the test tube B and C in a water bath set at 37° C for 15 minutes.

To test tube B add 2 drops of iodine solution. Note the colour change.

To test tube C, add 2 rrd of Fehling’ s solution. Keep the test tube at 100° C for 10 minutes. Note the colour change.

Answer the following questions:

(i)Write your observations and the inference drawn for each of the two test tubes B and C in the form of a table given below:      [4]

Test tube                   Observation                        Inference

B                                       ……                                       …….
C                                       ……                                       …….

(ii)  Identify the two solutions S~ and S2 on the basis of the experiment.

(iii) State the reason for your observation in the test tube C.

(b) An experiment was performed for the isolation of plasmid DNA. As a result,  DNA bands appeared on the gel. A photograph, labelled D of the gel with DNA bands has been placed before you.

Answer the following questions:

(i) Name the biochemical technique demonstrated in the photograph.
(ii) Mention the basic principle on which this biochemical technique is based.
(iii) What is the application of plasmids in genetic engineering?
(iv) Given two differences between Plasmid DNA and Genomic DNA.

Question 2

You have been given two solutions P and Q: Solution P is 0.01 M Acetic acid.

.                                                                                       : Solution Q is 0.01 M Sodium

.                                                                                          acetate (Molecular weight of

.                                                                                           Sodium acetate is 136.08).

 

 

Proceed as follows:

Note the pH of solution P and solution Q separately with the help of pH paper.

Take 10 mi of each of the solutions P and 9 in a beaker labelled J. Mix the contents of the’ beaker well. Note the pH of the well mixed solution.

Pour 5 mi of the solution in the beaker M inW each of the three test tubes Ta Ta and Ts.

To the test tube T~ add one drop of distiUed water and not the pH.

To the test tube Ts, add one drop of O. 01 N HCl with a dropper. Shake the mixture gently and not the pH.

To the test tube T3, add one drop of O. O IN HCl with a dropper. Shake the mixture gently and not the pH.

Answer the following questions:       [5]

(1) Report the pH values of the following solutions in the form of a table given below

SOLUTIONS IN pH
Beaker M
Test tube Ts
Test tube T2
Test tube Ts

(ii) If you were to prepare 0.01 M Sodium acetate solution, how many grams of Sodium acetate would you dissolve in distilled water to make 1000 mi of the solution?

(iii) On adding a drop of 0.01 N HC1 to test tube Ts, did the solution in the test tube undergo a pH change? Give a reason for your answer,

(iv) What do you understand by the term buffering capacity?

(v) What is the effect of increase in temperature on the pH value of a solution?

Question 3        [6]

You are given a Petri plate labelled X, containing bacterial culture, Perform the following experiment:

Prepare a bacterial smear on a slide. Allow it to dry for 5 minutes. Next, stain it with crystal violet stain. Rinse the slide gently with distilled water.

Add a few drops of iodine solution. Against rinse off the extra stain with distilled water.

Add a few drops of 90% ethanol. Counter stain the slide with saffranin solution. Rinse off the excess stain with distilled water. Observe the slide under the microscope.

Answer the following questions:       [6]

(i) Name the technique used in the above experiment.

(ii) What do you observe when the slide is placed under the microscope?

(iii) Write the principle on which this technique is based.

(iv)  How is this technique useful in micro-biology experiments?

(v) Given one example each of gram+ve and gram-ye bacteria.

Question 4      [6]

Identify the displayed instruments/photographs of instruments, labelled I to 4.

For each instrument, write:

 (i)   The name.
(ii)  One important structural feature.
(iii) One specific use of the instrument.

SECTION B

Question 5      [10]

(a) Show your Project Work/Assignment to the Visiting Examiner for assessment.

(b) Submit your Practical File to the Visiting Examiner for assessment.

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