Biology, Eighth Edition (Raven)

Chapter 18: Genomics

Construction of a Plasmid Vector

Why are plasmids powerful biotechnology tools? Plasmids are extraordinarily useful in the manipulation of genes because they are essentially tiny, self-contained genomes. A plasmid can be moved from cell to cell easily. They also contain the genes that control their own replication. Therefore they can be used to move and to copy any gene that can be inserted into the plasmid. Plasmids also do not usually have detrimental effects on their host cells.

View the animation below, then complete the quiz to test your knowledge of the concept.


1.	In insertional inactivation

		A)	if foreign DNA is inserted, the beta galactosidase marker is inactivated, and the colonies remain white
		B)	if foreign DNA is inserted, the beta galactosidase marker is inactivated, and the colonies turn blue
		C)	if foreign DNA is inserted, the beta galactosidase marker is activated, and the colonies remain white
		D)	if foreign DNA is inserted, the beta galactosidase marker is activated, and the colonies turn blue

2.	If host cells are ampicillin sensitive and are plated on a medium containing ampicillin

		A)	only cells that have not taken up the ampicillin resistant vector can grow
		B)	only cells that have taken up the ampicillin resistant vector can grow
		C)	all cells will grow
		D)	ampicillin is inactivated

3.	The lac z gene marker codes for

		A)	b galactosidase, which splits x-gal
		B)	b galactosidase, which makes x-gal resistant to splitting
		C)	ampicillin resistance
		D)	white colonies

4.	When foreign DNA and plasmid are both cut with the same restriction enzyme and mixed together, all molecules will form recombinants.

		A)	True
		B)	False

5.	When beta galactosidase cleaves x-gal, white colonies result.

		A)	True
		B)	False