Restriction enzymes and gel electrophoresis — practice questions

Question 1 · difficulty L2 · understanding

Given below are two statements: Statement 1 : The DNA fragments extracted from gel electrophoresis can be used in construction of recombinant DNA. Statement II : Smaller size DNA fragments are observed near anode while larger fragments are found near the wells in an agarose gel. In the light of the above statements, choose the most appropriate answer from the options given below :

• A. Statement I is correct but statement II is incorrect
• B. Statement I is incorrect but statement II is correct
• C. Both statement I and statement II are correct
• D. Both statement I and statement II are incorrect

Question 2 · difficulty L3 · understanding

Which of the following statements are not true regarding restriction endonucleases? A. They are called molecular scissors. B. These are the enzymes responsible for restricting the growth of bacteriophages in E. coli. C. They cut the DNA only at the centre of the palindromic sites. D. They remove nucleotides only from the ends of DNA fragments. E. They recognise specific palindromic base-pair sequences. Choose the answer from the options given below :

• A. A and B only
• B. A and E only
• C. D and E only
• D. C and D only

Question 3 · difficulty L3 · understanding

Which of the following statements are correct with respect to DNA separation, isolation and visualization? A. The cutting of DNA is done by molecular scissors. B. The DNA fragments separate according to their size in an agarose gel, upon electrophoresis. C. The separated DNA fragments can be seen without staining when exposed to UV light. D. The separated DNA fragments, when stained with ethidium bromide, can be seen in visible light. Choose the correct answer from the options given below :

• A. B and D only
• B. A and B only
• C. B and C only
• D. A and D only

Question 4 · difficulty L3 · understanding

Which of the following enzyme(s) are NOT essential for gene cloning? A. Restriction enzymes B. DNA ligase C. DNA mutase D. DNA recombinase E. DNA polymerase Choose the correct answer from the options given below:

• A. D and E only
• B. B and C only
• C. C and D only
• D. A and B only

Question 5 · difficulty L3 · understanding

Identify the incorrect statement related to gel electrophoresis.

• A. Separated DNA fragments can be directly seen under UV radiation
• B. Separated DNA can be extracted from gel piece
• C. Fragment of DNA moves toward anode
• D. Sieving effect of agarose gel helps in separation of DNA fragments

Question 6 · difficulty L3 · understanding

Recombinant DNA molecule can be created normally by cutting the vector DNA and source DNA respectively with:

• A. Hind II, Hind II
• B. Hind II, Alu I
• C. Hind II, EcoR I
• D. Hind II, BamHI

Question 7 · difficulty L3 · understanding

Select the restriction endonuclease enzymes whose restriction sites are present for the tetracycline resistance (tet$$^{\mathrm{R}}$$) gene in the pBR322 cloning vector.

• A. Bam HI and Sal I
• B. Sal I and Pst I
• C. Pst I and Pvu I
• D. Pvu I and Bam HI

Question 8 · difficulty L3 · understanding

Which of the following are correct about EcoRI? A. Cut the DNA with blunt end B. Cut the DNA with sticky end C. Recognise a specific palindromic sequence D. Cut the DNA between the base $$\mathrm{G}$$ and $$\mathrm{A}$$ when encounters the DNA sequence 'GAATTC' E. Exonuclease Choose the correct answer from the options given below:

• A. B, C, E only
• B. A, D, E only
• C. A, C, D only
• D. B, C, D only

Question 9 · difficulty L3 · understanding

Hind II always cuts DNA molecules at a particular point called recognition sequence and it consists of:

• A. 8 bp
• B. 6 bp
• C. 4 bp
• D. 10 bp

Question 10 · difficulty L3 · understanding

Match List I with List II. List - I List - II (A) Kanamycin (I) Delivers genes into animal cells (B) ClaI (II) Selectable marker (C) Disarmed retroviruses (III) Restriction site (D) Kanamycin $$^\mathrm{R}$$gene (IV) Antibiotic resistance Choose the correct answer from the options given below :

• A. (A)-(II), (B)-(III), (C)-(I), (D)-(IV)
• B. (A)-(III), (B)-(I), (C)-(IV), (D)-(II)
• C. (A)-(IV), (B)-(III), (C)-(I), (D)-(II)
• D. (A)-(II), (B)-(IV), (C)-(I), (D)-(III)