Sunday, January 3, 2021

Biotechnology: Principles and Processes | Class 12 Botany| Previous Years Questions and Answers (2018 to 2020)

4. BIOTECHNOLOGY: PRINCIPLES AND PROCESSES


2020 SAY

1.   Observe the figure given below: (2)

Fill in the blanks a, b, c, d in the figure. (Hint: a, b, c – stages, d – enzyme).

ü Answer:

(a) Denaturation

(b) Annealing

(c) Extension

(d) Taq polymerase

2.   EcoRI is a restriction endonuclease. What do E, Co, R, I represent? (2)

ü Answer:

E = Escherichia (Genus name of bacteria)

Co = Coli (Species name of bacteria)

R = Strain

I = First extracted enzyme (Order of extraction).

2020 MARCH

1.   Which among the following is a selectable marker in pBR - 322? (1)

a.      "Ori"                           b.   Hind III

c.      ampR                           d.   rop

ü Answer:

(c) ampR

2.   How can we make a host cell competent to receive a foreign gene or DNA? (2)

ü Answer:

Treating the cells with specific concentration of a divalent cation such as calcium.

Incubating the cells with recombinant DNA on ice. Place them briefly at 420C (heat shock). Again, place them back on ice.

3.   The following are the diagrams of two important processes used in rDNA technology. (3)


a.   Identify A and B.

b.   Write the uses of A and B in rDNA technology.

ü Answer:

(a) A= Polymerase Chain Reaction (PCR)

B= Gel electrophoresis.

(b) PCR is used for the amplification of gene of interest.

     Gel electrophoresis is used to separate DNA fragments of different sizes.

2019 SAY June

1.   Restriction endonuclease recognises a specific sequence in the DNA. Name that sequence and write its peculiarity. (2)

ü Answer:

Palindromic nucleotide sequence.

Peculiarity: It is a sequence of base pairs that read the same on the two strands in 5' → 3' direction and in 3' → 5' direction.

2.   Match the items of column A with B: (2)

A

B

(a) Cloning Vector

(b) Separation of DNA fragments

(c) PCR

(d) Converts raw materials into specific products

(i) Bioreactor

(ii) Taq polymerase

(iii) Electrophoresis

(iv) Hind 11

(v) pBR322

 

ü Answer:


A

B

(a) Cloning Vector

(b) Separation of DNA fragments

(c) PCR

(d) Converts raw materials into specific products

(v) pBR322

(iii) Electrophoresis

(ii) Taq polymerase

(i) Bioreactor

 

2019 MARCH


1.   What is the function of Restriction Endonuclease in recombinant DNA technology? (1)

a.  Link together fragments of DNA

b.  Make millions of copies of DNA

c.  Cut DNA into many fragments.

d.  Separate fragments of DNA

ü Answer:

(c) Cut DNA into many fragments


2.   Recombinant DNA technology is a complex process which involves several steps. Write down the major steps in recombinant DNA technology. (3)

ü Answer:

1. Isolation of the Genetic Material (DNA).

2. Cutting of DNA by restriction enzymes.

3. Amplification of Gene of Interest using PCR.

4. Insertion of Recombinant DNA into Host Cell.

5. Obtaining the Foreign Gene Product.

6. Downstream Processing.


3.   The discovery of Restriction Endonuclease is considered as "milestone" in the history of genetic engineering. (3)

a.  Which is the first discovered restriction endonuclease?

b.  What are the criteria for naming of restriction endonuclease?

ü Answer:

(a) Hind II.

(b) First capital letter: Genus name.

Second two letters: Species name.

Fourth letter: Strain of bacterium from which the enzyme is isolated.

Roman number: Order of isolation of enzyme.


2018 SAY June


1.   'In Gel electrophoresis, the separated DNA fragments can be visualized after staining. Name the stain used for it. (1)

ü Answer:

Ethidium bromide.


2.   Multiple copies of gene of interest can be synthesised in vitro. Name the technique and its requirements. (2)

ü Answer:

Polymerase Chain Reaction (PCR).

Requirements: Primase, Taq polymerase, Target DNA etc.


3.   Restriction endonuclease enzymes are used to cut the DNA at specific sequence. (3)

a.  Write the name of first isolated one.

b.  Write the convention for naming these enzymes.

ü Answer:

(a) Hind II

(b) First capital letter: Genus name.

Second two letters: Species name.

Fourth letter: Strain of bacterium from which the enzyme is isolated.

Roman number: Order of isolation of enzyme.


2018 MARCH

1.    The DNA fragments can be separated using gel electrophoresis. (2)

a. Name the gel used in this technique.

b. Write the name of technique used to remove the DNA from the gel.

ü Answer:

(a)  Agarose gel.

(b)  Elution.

2.   Observe the following figure. (2)


a.   Identify the figure.

b.   What does (i) tetR (ii) rop (iii) ori denote?

ü Answer:

(a) pBR322 (E. coli cloning vector).

(b) (i) Tetracycline resistance gene

(ii) Gene that codes for the proteins involved in the replication of plasmid.

(iii) Origin of replication.


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