Question

A eukaryotic gene has "sticky ends" produced by the restriction endonuclease EcoRI. The gene is added to a mixture containing EcoRI and a bacterial plasmid that carries two genes conferring resistance to ampicillin and tetracycline. The plasmid has one recognition site for EcoRI located in the tetracycline resistance gene. This mixture is incubated for several hours, exposed to DNA ligase, and then added to bacteria growing in nutrient broth. The bacteria are allowed to grow overnight and are streaked on a plate using a technique that produces isolated colonies that are clones of the original. Samples of these colonies are then grown in four different media: nutrient broth plus ampicillin, nutrient broth plus tetracycline, nutrient broth plus ampicillin and tetracycline, and nutrient broth without antibiotics. Bacteria that contain the plasmid, but not the eukaryotic gene, would grow:_________.
a. in the nutrient broth without antibiotics only.
b. only in the broth containing both antibiotics.
c. in the nutrient broth plus ampicillin, but not in the broth containing tetracycline.
d. in all four types of broth.
e. in the broth containing tetracycline, but not in the broth containing ampicillin.

Answer 1

Answer:

option C

Explanation:

In the middle of tetracycline resistance gene, the recognition site is located

The resistance for tetracycline is lost, since the plasmid is cleaved at the middle of tetracycline resistance gene,

The genetically engineered plasmid will contain only ampicillin resistant gene.

Conclusively, the bacteria containing the genetically engineered plasmid would grow in both nutrient broth and the ampicillin broth, and not in in the broth containing tetracycline.

Therefore, option C is correct.

Answer 2

Answer:

I believe that the answer is D. In all four types of broth

Explanation: