Chapter 14, Problem 2STP

Summary Introduction

Introduction:

Researchers use genetic engineering to manipulate DNA. It makes possible to produce organisms that contain individual genes from another organism. Recombinant DNA contains DNA from different sources. It can be made by connecting fragments of DNA from different sources. DNA ligase is used to join a plasmid DNA and a DNA fragment obtained from another genome to create a recombinant plasmid DNA.

Answer to Problem 2STP

Correct answer :

The correct answer is option C. Cells A and B did not take up the DNA fragment

Explanation of Solution

Explanation/justification for the correct answer:

Option C. Cells A and B did not take up the DNA fragment - 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. 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.Hence this is the correct option.

  

Explanation for incorrect answer:

Option A. Cells A and B are resistant to antibiotics- 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. However, some bacterial cells do not take up the plasmid DNA. Cells A and B are not resistant to antibiotics.Hence this is not the correct option.

Option B. Cells A and B do not have plasma membranes - The illustration given 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. However, some bacterial cells do not take up the plasmid DNA. Cells A and B have plasma membranes. Hence, this is not the correct option.

Option D. Cells A and B initially had different plasmids −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. However, some bacterial cells do not take up the plasmid DNA.Cells A and B initially had similar plasmids. Hence this is not the correct option.