Chapter 14, Problem 3STP

Summary Introduction

Introduction:

To make large quantities of recombinant plasmid DNA, bacterial cells are mixed with recombinant plasmid DNA. Some bacteria take up the recombinant plasmid DNA through a process called transformation. Brief heating or short electric pulse creates openings in the plasma membrane of bacterial cells which allow recombinant plasmid DNA to enter the bacterial cells. However some bacterial cells do not take up the plasmid DNA.

Answer to Problem 3STP

Correct answer :

The correct answer is option C. Cells without new plasmid will die after exposure to an antibiotic

Explanation of Solution

Explanation/justification for the correct answer:

Option C. Cells without new plasmid will die after exposure to an antibiotic - The illustration given below shows bacteria that were transformed after they were mixed with the recombinant DNA. Cells A and B do not have the new recombinant DNA plasmid. After transformation the bacteria are allowed to grow on a plate containing an antibiotic. The transformed bacteria are able to survive as they contain the gene for antibiotic resistance and the normal bacteria die. Hence this is the correct option.

  

Explanation for incorrect answer:

Option A. Cells with new plasmid will die after exposure to an antibiotic - The illustration given below shows bacteria that were transformed after they were mixed with the recombinant DNA. Cells A and B do not have the new recombinant DNA plasmid. After transformation the bacteria are allowed to grow on a plate containing an antibiotic. The transformed bacteria are able to survive as they contain the gene for antibiotic resistance and the normal bacteria die.

Hence this is not the correct option.

Option B. Cells with the new plasmid will replicate quicker - The illustration given below shows bacteria that were transformed after they were mixed with the recombinant DNA. Cells A and B do not have the new recombinant DNA plasmid. After transformation the bacteria are allowed to grow on a plate containing an antibiotic. The transformed bacteria are able to survive as they contain the gene for antibiotic resistance and the normal bacteria die. Hence this is not the correct option.

Option D. Cells without the new plasmid will replicate more quickly − The illustration given below shows bacteria that were transformed after they were mixed with the recombinant DNA. Cells A and B do not have the new recombinant DNA plasmid. After transformation the bacteria are allowed to grow on a plate containing an antibiotic. The transformed bacteria are able to survive as they contain the gene for antibiotic resistance and the normal bacteria die. Hence this is not the correct option.