BIOTECHNOLOGY :PRINCIPLE AND PROCESS CLAS XII

 

GANGWAR SIR BIOZONE

BIOLOGY

Class: 12 (2025-26)

CLASS TEST

TIME: 1.5 HOURS	M.M.: 42

General Instructions:

• This question paper contains 22 questions.

• All questions are compulsory.

• Q.1 to 5 (Multiple Choice Questions (MCQs)): 5 questions. Each question carries 1 mark.

• Q.6 to 8 (Assertion Reason Questions): 3 questions. Each question carries 1 mark.

• Q.9 to 13 (Very Short Answer Questions): 5 questions. Each question carries 1 mark.

• Q.14 to 18 (Short Answer Questions): 5 questions. Each question carries 2 marks.

• Q.19 to 21 (Long Answer Questions): 3 questions. Each question carries 5 marks.

• Q.22 to 22 (Competency Based Questions): 1 questions. Each question carries 4 marks.

Topics Covered:

• Biotechnology: Principles and Processes

 

Q.NO.	QUESTIONS	MARKS
MULTIPLE CHOICE QUESTIONS (MCQS) Questions 1 to 5 (5 questions × 1 mark each)
1	Which of the following is commonly used as 'molecular scissors' in genetic engineering? A. Restriction enzymes B. DNA ligase C. DNA polymerase D. RNA polymerase	1
2	In recombinant DNA technology, antibiotic resistance genes are primarily used for: A. Cutting DNA at specific sites B. Linking DNA fragments C. Selecting transformed host cells D. Amplifying target DNA	1
3	During PCR, the step involving cooling the reaction to 50-60°C is meant for: A. Denaturation of DNA B. Extension by Taq polymerase C. Primer annealing D. DNA synthesis	1
4	In gel electrophoresis, DNA fragments separate based on their: A. Charge B. Size C. Colour D. Sequence	1
5	The purpose of adding 'elution' buffer in DNA extraction is to: A. Break open cells to release DNA B. Precipitate DNA from solution C. Dissolve purified DNA D. Separate DNA from proteins	1
ASSERTION REASON QUESTIONS Questions 6 to 8 (3 questions × 1 mark each) Instructions: The following questions consist of two statements – Assertion (A) and Reason (R). Answer these questions by selecting the appropriate option given below: A. Both A and R are true, and R is the correct explanation of A. B. Both A and R are true, and R is not the correct explanation of A. C. A is true but R is false. D. A is false but R is true.
6	Assertion (A): Restriction enzymes are called molecular scissors.  Reason (R): They cut DNA at specific recognition sites.	1
7	Assertion (A): E. coli is commonly used as a host organism in recombinant DNA technology.  Reason (R): E. coli has a high growth rate and can multiply quickly.	1
8	Assertion (A): Gel electrophoresis is used to separate DNA fragments.  Reason (R): DNA fragments move towards the anode due to their negative charge.	1
VERY SHORT ANSWER QUESTIONS Questions 9 to 13 (5 questions × 1 mark each)
9	Explain the role of selectable markers in vector DNA.	1
10	Name the bacterium that produces the restriction enzyme EcoRI.	1
11	What is the function of Taq DNA polymerase in PCR technology?	1
12	Why is agarose gel used as a matrix for DNA separation in gel electrophoresis?	1
13	Analyze why the origin of replication (ori) in a cloning vector must be a high-efficiency sequence.	1
SHORT ANSWER QUESTIONS Questions 14 to 18 (5 questions × 2 marks each)
14	Name the two enzymes that are essential for cutting and joining DNA fragments during recombinant DNA technology.	2
15	Explain why only one restriction site in a vector is insufficient for gene cloning.	2
16	A circular plasmid has three restriction sites for EcoRI. If completely digested with EcoRI, how many DNA fragments will be produced? Justify your answer.	2
17	Describe the temperature conditions required for the three main steps of PCR (denaturation, annealing, extension).	2
18	Analyze how antibiotic resistance genes function as selectable markers in plasmid vectors during bacterial transformation.	2
LONG ANSWER QUESTIONS Questions 19 to 21 (3 questions × 5 marks each)
19	Explain the three fundamental steps involved in the Polymerase Chain Reaction (PCR) technique. Describe the role of each step in DNA amplification.	5
20	List and describe the five essential tools required for recombinant DNA technology.	5
21	A student performed gel electrophoresis on DNA fragments of 500 bp, 1000 bp, and 2000 bp. Describe the expected results and explain why the fragments separate in this manner. Include the principle behind this separation technique.	5
COMPETENCY BASED QUESTIONS Questions 22 to 22 (1 questions × 4 marks each)
22	At Innovate Biotech Research Institute, scientists are developing a recombinant DNA vaccine against a novel viral pathogen. The team has isolated the viral surface antigen gene (1200 bp) and needs to insert it into a bacterial plasmid vector (pET-28a) for mass production. They've selected EcoRI restriction sites (G↓AATTC) in both the gene and plasmid, but post-ligation experiments show unexpected multiple band patterns during agarose gel electrophoresis of recombinant plasmids. A. Design a complete process flow chart detailing each biotechnological step from gene isolation to recombinant plasmid insertion B. Evaluate why using the same restriction enzyme for both insert and vector might lead to improper orientation of the gene insert C. Propose a modified restriction enzyme strategy to ensure unidirectional cloning of the antigen gene D. Analyze how improper antibiotic selection pressure could compromise the selection of recombinant colonies E. Create a troubleshooting protocol to identify whether the multiple bands result from partial digestion or plasmid dimer formation	4