The S phase of the cell cycle
No, a virus is not a cell at all. It is neither prokaryotic nor eukaryotic but can invade either in order to replicate itself. Viruses that invade prokaryotes are called bacteriophages.
during S (DNA synthesis) phase of the cell cycle
Nothing
In normal eukaryotic cell cycle or in case of bacterial chrosome, DNA replication occur to replicate the whole chromosome.
There is evidence to suggest that mitochondria were once free-living organisms that were incorporated into an ancestoral eukaryotic cell. Not only do they have their own DNA, but they replicate independantly of the larger host cell replicating.
Yes, eukaryotes can divide and replicate. In fact, eukaryotic cells have a well defined, sequential cell cycle too.
Cells do not replicate "In DNA". Cells replicate their DNA during the process of cell division.
During synthesis stage of the cell cycle
No, a virus is not a cell at all. It is neither prokaryotic nor eukaryotic but can invade either in order to replicate itself. Viruses that invade prokaryotes are called bacteriophages.
during S (DNA synthesis) phase of the cell cycle
Yes, it is possible for a Eukaryotic cell to have no nucleus. An example of a cell without a nucleus is the mammalian red blood cell. However, Eukaryotic cells without a nucleus, like red blood cells, are unable to replicate. This is why red blood cells need to be continuously produced in the bone marrow.
Chromosomes replicate during cell division, so are present as a new cell forms.
A fat cell is a eukaryotic cell. All of the cells in a eukaryotic organism are eukaryotic.
Nothing
Nothing
Eukaryotic
eukaryotic