Figure 27.2 depicts changes to the amount of DNA present in a recipient cell that is engaged in conjugation with an Hfr cell. Hfr cell DNA begins entering the recipient cell at Time A. Assume that reciprocal crossing over occurs (in other words, a fragment of the recipient's chromosome is exchanged for a homologous fragment from the Hfr cell's DNA). Use Figure 27.2 to answer the following questions.

Figure 27.2
-Which two processes are responsible for the shape of the curve at Time B?
1)transduction
2)entry of single-stranded Hfr DNA
3)rolling circle replication of single-stranded Hfr DNA
4)activation of DNA pumps in plasma membrane
A) 1 and 2
B) 1 and 4
C) 2 and 3
D) 2 and 4
E) 3 and 4

Question

Figure 27.2 depicts changes to the amount of DNA present in a recipient cell that is engaged in conjugation with an Hfr cell. Hfr cell DNA begins entering the recipient cell at Time A. Assume that reciprocal crossing over occurs (in other words, a fragment of the recipient's chromosome is exchanged for a homologous fragment from the Hfr cell's DNA). Use Figure 27.2 to answer the following questions.
  
Figure 27.2
-Which two processes are responsible for the shape of the curve at Time B?
1)transduction
2)entry of single-stranded Hfr DNA
3)rolling circle replication of single-stranded Hfr DNA
4)activation of DNA pumps in plasma membrane
A) 1 and 2 
B) 1 and 4 
C) 2 and 3 
D) 2 and 4 
E) 3 and 4

Quizplus · Accepted Answer

The shape of the curve at Time B is due to the combined processes of entry of single-stranded Hfr DNA and rolling circle replication of single-stranded Hfr DNA. This results in the gradual increase of the amount of DNA in the recipient cell. Transduction and activation of DNA pumps in plasma membrane are not relevant to the process of conjugation with an Hfr cell.

Figure 272 Depicts Changes to the Amount of DNA Present in in a Recipient