When E. coli that has been transformed by pGLO is grown on nutrient agar plates

Question

When E. coli that has been transformed by pGLO is grown on nutrient agar plates (LB) containing ampicillin but not arabinose, the ?-lactamase and araC genes are expressed.

a) Why is it useful in the transformation experiment, for the plasmid to carry a gene for antibiotic resistance?

b) Under these growth conditions, what is the protein, araC, interacting with? What is the result of that interaction on gene expression in the transformed cells?

c) How is the function of araC changed when arabinose is present in the growth medium such that the phenotype of the transformed E. coli is changed, allowing the cells to fluoresce when exposed to UV light?

Explanation / Answer

a.Plasmids are essential for the survival of bacteria under stress.And here,the stress is in the form of presence of antibiotic.So,the plasmid must have genes for antibiotic resistance to help the bacteria survive under this stress.

b.The arabinose operon repressor (araC) gene which encodes a repressor protein that ensures that the GFP gene of pGLO is expressed only when glucose in the growth medium is replaced by arabinose.

c.When bacteria transformed with pGLO containing a wild?type copy of the GFP gene are grown in the presence of arabinose, they fluoresce a brilliant green color under UV light.

Related Questions

Navigate

• Browse (All)
• Browse W
• Subjects

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.