1. A biologist measured the amount of DNA in several single diploid cells taken from a culture. He knew that these cells could divide mitotically, but not meiotically. His data is shown below:
Cell Number and DNA content in micrograms:
Cell 1 (11.1 micrograms) Cell 2 (5.4 micrograms)
Cell 3 (7.3 micrograms) Cell 4 ( 10.9 micrograms)
Cell 5 (5.6 micrograms) Cell 6 (8.6 micrograms)
Cell 7 (11.0 micrograms)
Which of these cells have most likely just completed mitosis and cytokinesis?
a. 1, 4, and 7
b. 3 and 6
c. 2, 3, 5, and 6
d. 2 and 5
e. No conclusion can be drawn from the data provided.
To determine which of these cells have most likely just completed mitosis and cytokinesis, we need to understand the process of mitosis and cytokinesis.
Mitosis is the process by which a cell divides to produce two genetically identical daughter cells. In this process, the DNA in the parent cell is replicated, and then the replicated chromosomes are divided equally between the two daughter cells.
Cytokinesis is the final stage of cell division, where the cytoplasm of the parent cell is divided into two, resulting in the formation of two separate daughter cells.
During cytokinesis, the amount of DNA in each daughter cell should be approximately half of the amount in the parent cell since the DNA is divided equally between them.
Looking at the data provided, we can see that the cells 1, 4, and 7 have higher amounts of DNA compared to the other cells. This suggests that these cells have just completed mitosis and cytokinesis, where the DNA was divided equally between the daughter cells.
Therefore, the correct answer is:
a. 1, 4, and 7