Which of the following is a technique used to encourage bacteria to take up DNA from the surrounding culture medium? A)pretreatment of bacteria with a brief heat shock, followed by exposure to Ca²⁺ ions B)pretreatment of bacteria with Cu²⁺ ions, followed by a brief heat shock C)pretreatment of bacteria with Ca²⁺ ions, followed by a brief heat shock D)pretreatment of bacteria with Ca²⁺ ions, followed by a brief cold shock E)pretreatment of bacteria with a brief heat shock, followed by exposure to Mg²⁺ ions

Question

Quizplus · Accepted Answer

Pretreatment of bacteria with Ca²⁺ ions, followed by a brief heat shock, is a common technique used to encourage bacteria to take up DNA from the surrounding culture medium. The Ca2+ ions neutralize the negatively charged cell membrane, allowing the DNA to pass through, while the brief heat shock creates pores in the membrane, further facilitating DNA uptake.

Which of the Following Is a Technique Used to Encourage