A scientist investigated DNA replication in two groups of cells, labeled A and B. She injected radioactively labeled nucleotides into cells of each group and allowed DNA replication to begin. When replication was halfway completed, she injected a drug into the cells to stop replication. She then examined the cells to determine the distribution of the newly-synthesized DNA. She found each cell of group A had many segments of new DNA in its nucleus, while each cell of group B had a single segment of new DNA in its cytoplasm. What can the researcher conclude about the cells?

A is a eukaryotic cell while B is a prokaryotic cell

Explanation:

The researcher can conclude that cell A is eukaryotic while cell B is prokaryotic.

In eukaryotic cells, the DNA is located majorly in the nucleus and the replication of the DNA happens in the nucleus. Hence, it is only logical to find segments of new DNA in the nucleus of cell A during replication.

Prokaryotic cells, however, lack a nucleus. Their DNAs lie freely within the cytoplasm. This thus means that replication can only happen in the cytoplasm. Hence, it follows logically to find a new DNA segment in the cytoplasm of cell B.

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