In a unipuppicorn, the somatic cells must make more cells in order to grow. If its somatic cells contain 18 chromosomes (as chromatin), how many chromosomes will it have at the end of the "S" phase? (You know this!! :)
a
9
b
18
c
36
d
72
e
144
The correct answer is b) 18.
During the "S" phase of the cell cycle, DNA replication occurs, resulting in the formation of identical copies of each chromosome. Therefore, the number of chromosomes remains the same, but the number of chromatids (the replicated copies of each chromosome) doubles. In this case, the unipuppicorn starts with 18 chromosomes and will still have 18 chromosomes at the end of the "S" phase.