A scientist inserts a DNA fragment encoding a mouse gene into the plasmid shown

Question

A scientist inserts a DNA fragment encoding a mouse gene into the plasmid shown below. The mouse DNA insert is cut with the enzyme XbaI at one end and with EcoRI at the other end. The plasmid is digested with the same two enzymes and combined with the insert in the presence of DNA ligase. The bacteria do not contain a lacZ gene or antibiotic resistance genes of their own.

kan = kanamycin (an antibiotic)

zeo = zeocin (an antibiotic)

R = resistance

Ori = replication origin

I. Which of the following correctly characterizes bacteria that are successfully transformed with the recombinant plasmid if they are placed onto growth medium containing X-gal?

A. kanamycin resistant; zeocin resistant; white colonies

B. kanamycin resistant; zeocin resistant; blue colonies

C. kanamycin resistant; white colonies

D. kanamycin resistant; blue colonies

E. zeocin resistant; white colonies

F. zeocin resistant; blue colonies

II. Which of the following would distinguish bacteria transformed with recombinant plasmid (plasmid containing the mouse gene insert) from those transformed with non-recombinant, uncut plasmid that does not contain the insert?

A. Sensitivity to kanamycin

B. Sensitivity to zeocin

C. Ability to break down X-gal

D. A and B

E. A and C

F. B and C

G. A, B, and C

Explanation / Answer

ANSWER:1. B

Because genes for kanamysin and zeosin are not interupted and inserted in vector , the bacteria becomes resistant for those genes, and due to the presence of lacz region blue colonies are formed.

2. c ability to breakdown xgal

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