Concept Check Questions (In Figure Legends)

CHAPTER 20

Concept check questions (in figure legends)

FIGURE20.1

Concept check: What is the purpose of using cyanogen bromide in this experiment?

Answer: Cyanogen bromide separates -galactosidase from the A or B chains.

FIGURE 20.3

Concept check: What is the difference between gene addition and gene replacement?

Answer: In gene addition, a cloned gene is added to an organism’s genome. In gene replacement, a cloned gene is swapped with a gene that is already present in the organism’s genome.

FIGURE 20.5

Concept check: What is the purpose of the NeoR gene?

Answer: The NeoR gene selects for cells that have taken up the cloned gene.

FIGURE 20.6

Concept check: What is the difference between a gene knockout versus a gene knockin?

Answer: A gene knockout replaces a normal gene with a gene that is inactivated. A gene knockin inserts a gene into a specific site in the genome.

FIGURE 20.7

Concept check: Why is a β-lactoglobulin promoter used?

Answer: The β-lactoglobulin promoter is used because it is expressed in mammary cells.

FIGURE 20.8

Concept check: In the protocol, why is the nucleus of the oocyte removed?

Answer: The nucleus of the oocyte is removed so the resulting organism contains (nuclear) genetic material only from the somatic cell.

FIGURE 20.9

Concept check: Is Carbon Copy a transgenic animal?

Answer: No. Carbon Copy has not received genetic material from a different species.

FIGURE 20.10

Concept check: Explain why stem cells are not depleted during the life of an organism.

Answer: When stem cells divide, they produce one cell that remains a stem cell and another cell that differentiates. This pattern maintains a population of stem cells.

FIGURE 20.12

Concept check: Are hematopoietic stem cells unipotent, multipotent, or pluripotent?

Answer: Multipotent

FIGURE 20.14

Concept check: Which portion of a T-DNA vector is transferred to a plant?

Answer: Only the T-DNA within the T-DNA vector is transferred to a plant.

FIGURE 20.17

Concept check: What are advantages and disadvantages of these two methods?

Answer: The liposome method is relatively safe in that it doesn’t evoke an immune response. A disadvantage is that it may be inefficient at getting the cloned gene into many cells. The retrovirus method is typically very good at getting the cloned gene into cells. A disadvantage is that it may cause a potentially harmful immune response.