A diploid cell contains 2n=2 chromosomes. What will be the number of DNA strands in this cell at G1, G2, Prophase I and Telophase II (per
nucleus), respectively?

A diploid cell, with a chromosome charge of 2n = 2 will have in:

G1 = 4 strands of DNA, two for each DNA molecule. G2 = 8 strands of DNA. Prophase I = 8 strands of DNA. Telophase II = 2 DNA strands per nucleus.

Explanation:

The cell cycle is divided, broadly speaking, into interphase and cell division (M). The process of division -by mitosis or meiosis- involves a series of intermediate steps that conclude with the production of two identical cells (diploid) or two cells with half the chromosome load (haploid), respectively.

In the G1 phase the cell is in interphase, so the nuclear DNA has not yet replicated. For a cell with 2n = 2, its nucleus has four strands of DNA. In G2 phase, after DNA replication, the number of DNA strands is doubled, so now in the cell nucleus of the cell there are 4 DNA molecules, each with double strands, so there is a total of 8 DNA strands. In prophase I of mitosis or meiosis the cell still does not divide there are 4 DNA molecules and 8 DNA strands, as in the previous step. In telophase II, which only occurs in meiosis, the chromosome charge has been halved, so each daughter cell will have one chromosome (n = 1), one single DNA molecule and 2 DNA strands per nucleus.