Question

You conduct an experiment by incorporating purple fluorescent dNTPs early in S phase, followed by gold fluorescent dNTPs late in S phase. At the conclusion of S-phase, you examine the nucleus of the cell using a fluorescent microscope and see that the only incorporated fluorescence is purple. Which one of the following represents the most likely interpretation of your results?

a. Most DNA replication is initiated late during S-phase.b. Most DNA replication is not initiated early during S-phase.c. DNA that is located at the periphery of the cell is replicated late in S phase.d. DNA synthesis initiates late during S-phase but not early during S-phase.e. DNA synthesis initiates early during S-phase but not late during S-phase.

Answer 1

E

Step-by-step explanation:

1. Cell have 2 phase: i) interphase and mitotic phase.

2. Interphase is further divided into 3 sub-phases known as: i) G1 phase, ii) S phase and iii) G2 phase.

3. DNA is synthesized by the process known as DNA replication. DNA replication occurs in S phase and it doubles the amount of DNA.

4 .The DNA polymerase enzyme is loaded on DNA molecule in the late G1 phase and DNA synthesis initiates during early S phase and complete DNA replicates in S phase,and occur only once.

5. So as given here, incorporating purple fluorescent dNTPs early in S phase, and followed by incorporation of gold fluorescent dNTPs late in S phase, the result is that only incorporated fluorescence is purple, this result is because as DNA synthesis initiates early during S-phase but not late during S-phase.