Figure 24.2 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 24.2 to answer the following question(s).
Figure 24.2
-During which two times can the recipient accurately be described as "recombinant" due to the sequence of events portrayed in Figure 24.2?
A)during times C and D
B)during times A and C
C)during times B and C
D)during times A and B
E)during times B and D

Question

Figure 24.2 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 24.2 to answer the following question(s).
  Figure 24.2
-During which two times can the recipient accurately be described as "recombinant" due to the sequence of events portrayed in Figure 24.2?
A)during times C and D 
B)during times A and C 
C)during times B and C 
D)during times A and B 
E)during times B and D

Quizplus · Accepted Answer

Recombination occurs when segments of DNA from the Hfr cell integrate into the recipient cell's genome via homologous recombination. Based on the graph, the recipient cell is still mostly composed of its own DNA at times A and B. However, at times C and D, the graph shows a significant increase in the amount of Hfr cell DNA present in the recipient cell. This suggests that during these times, the two cells have undergone enough homologous recombination for the recipient cell to be accurately described as "recombinant".

Figure 242 Depicts Changes to the Amount of DNA Present in in a Recipient