Transformation is the process by which foreign DNA is taken up by a bacterial cell. A cross-section of a bacterial cell about to begin this process is depicted here, with its circular chromosome shown inside. A foreign DNA molecule, shown in red, enters the bacterial cell through a receptor site on the membrane, shown in blue. One of the new strands of DNA is integrated into the host chromosome by strand displacement, a process whereby the new strand invades the host DNA and replaces a homologous segment of one of its two strands. The hybrid DNA molecule is replicated and the transforming DNA is transmitted to one of the two daughter cells.

Question 1: What happens during transformation?
  1. Foreign DNA enters a bacterial cell
  2. DNA is integrated into host chromosome
  3. Hybrid DNA replicates
  4. All of the above

Answer 1

Answer - (d) All of the above

Question 2: During transformation, one of the strands of the foreign DNA is integrated into the host chromosome by strand __________.
  1. replication
  2. displacement
  3. addition
  4. integration

Answer 2

Answer - (b) displacement