In a Yeast Two-Hybrid Analysis of Several Strains Containing Different

question 65

Multiple Choice

In a yeast two-hybrid analysis of several strains containing different prey/bait combinations, the screening of interacting proteins is done by growing cells on a medium containing X-Gal. White and blue colonies are observed after incubation. Which of the following statements is NOT true regarding blue/white selection in the yeast two-hybrid method?

• A) Blue colonies result from X-Gal hydrolyzed by the reporter enzyme b-galactosidase.
• B) White colonies result from cells in which the prey and bait proteins do not interact.
• C) Galactose released from X-Gal hydrolysis does not contribute to a colony's blue color.
• D) White colonies indicate that b-galactosidase catalyzed the hydrolysis of X-Gal.
• E) Blue colonies are an indication that GAL4 activated transcription of GAL1-lacZ.

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Definitions:

Whole-Genome Structure

The complete three-dimensional arrangement of all the DNA within an organism's genome, encompassing both its linear sequence and spatial organization within the cell nucleus.

Restriction Enzyme

Type of enzyme that cuts DNA at a specific sequence.

DNA Nucleotide Sequences

The precise order of nucleotides (adenine, thymine, cytosine, and guanine) in a segment of DNA, which determines genetic information.

Ti Plasmid

A plasmid found in the bacterium Agrobacterium tumefaciens, used in genetic engineering to transfer genes to plant cells.