Question

Because natural transformation is difficult to achieve with many organisms, including E. coli, Cohen and Boyer developed a procedure that is commonly used today whereby host cells are made competent to take up foreign DNA by treating with _______ cations and transformed by _____ the cells.

A. divalent; heat shocking

B. monovalent; freezing and thawing

C. monovalent; heat shocking

D. divalent; freezing and thawing

Answer 1

Answer:

Because natural transformation is difficult to achieve with many organisms, including E. coli, Cohen and Boyer developed a procedure that is commonly used today whereby host cells are made competent to take up foreign DNA by treating with divalent cations and transformed by heat shocking the cells.

• A. divalent; heat shocking - Correct Option (Explanation: Divalent cations such as calcium ions are used in chemical based transformation method. Bacterial cells are made compentent by treating first with calcium ions and then a heat shock is applied to transform the cells with recombinant foreign DNA)
• B. monovalent; freezing and thawing
• C. monovalent; heat shocking
• D. divalent; freezing and thawing