Recombinant DNA Technology MCQs

Question 1

The basis for blue-white screening with pUC vectors is

Accepted Answer

Intraallelic complementation

Answer

Intergenic complementation

Answer

Intragenic suppression

Answer

Extragenic suppression

Question 2

Phage T7 promoter containing plasmids are used for over-expression of cloned genes because

Accepted Answer

Exquisite specificity of T7 RNA polymerase to phage promoters

Answer

Their convenient size

Answer

Their single stranded nature

Answer

T7 infects E. coli and lysogenizes the cell

Question 3

Though the right border (RB) and left border (LB) of T-DNA are identical, the DNA transfer is specific for the DNA left of the RB (the T-DNA), rather than for the DNA left of the LB because

Accepted Answer

The sequence context at the RB defines the direction of transfer

Answer

The sequence context at the LB defines the direction of transfer

Answer

The nuclear location sequence (NLS) of VirD2 protein drives the excised T-strand

Answer

The endonuclease activity of VirD2 protein allows nicking at RB

Question 4

The restriction endonuclease Eco52I recognizes the sequence C/GGCGG and cuts between the first C and the first G, indicated by the slash. DNA cut by which of the following enzymes (given with their recognition sequences and cut sites) could be cloned into a plasmid digested with Eco52I?

Accepted Answer

XmaIII (C/GGCGG)

Answer

EcoRI (G/AATTC)

Answer

SmaII (CCCC/GGG)

Answer

SacII (CCGC/GG)

Question 5

Which of the following are commonly used as reporter genes? P. NPTgene Q. Luciferase gene R. CFTR gene S. GFP gene

Accepted Answer

Q, S

Answer

R, S

Answer

P, R

Answer

P, Q

Question 6

Which one of the following statements about Agrobacterium Ti plasmid is correct?

Accepted Answer

Opine biosynthesis genes are located within the T-DNA segment

Answer

Vir genes are located within the T-DNA segment

Answer

Phytohormone biosynthesis genes are located outside the T-DNA segment

Answer

Opine catabolism genes are located within the T-DNA segment

Question 7

Match the items in Group I with Group II. Group I (Vectors) Group II (Maximum DNA packaging) P. λ phage 1. 35 - 45 kb Q. Bacterial Artificial Chromosomes (BACs) 2. 100 - 300 kb R. P1 derived Artificial Chromosomes (PACs) 3. ≤ 300 kb S. λ cosmid 4. 5 - 25 kb

Accepted Answer

P-4, Q-3, R-2, S-1

Answer

P-3, Q-4, R-1, S-2

Answer

P-1, Q-3, R-2, S-4

Answer

P-1, Q-2, R-3, S-4

Question 8

A single base pair of DNA weighs 1.1 × 10-21 grams. How many picomoles of a plasmid vector of length 2750 bp are contained in 1 μg of purified DNA?

Accepted Answer

0.55

Answer

0.3

Answer

0.25

Answer

0.91

Question 9

Many plasmids have ampr marker. This implies

Accepted Answer

The plasmid contains the gene encoding β-lactamase

Answer

The plasmids contain genes for ampicillin biosynthesis

Answer

Ampicillin is required for bacterial growth after transformation

Answer

Ampicillin is essential for cell survival