In a cell with 4 chromosomes in G1 phase, what is its ploidy?

To determine the ploidy of a cell, we need to understand what ploidy refers to. Ploidy describes the number of sets of chromosomes in a cell. In G1 phase, the cell has completed its previous round of division and has not yet duplicated its chromosomes, meaning it contains the total number of chromosomes that will be present prior to DNA replication.

A cell with 4 individual chromosomes in G1 suggests that this is the total chromosome count in that phase. If these chromosomes are organized into pairs (one from each parent), this indicates that the cell is diploid, which is the term used to describe a cell containing two complete sets of chromosomes—one set inherited from each parent.

Thus, in this context, when the cell is described as containing 4 chromosomes, it implies that it has two sets of chromosomes, confirming its diploid nature. In contrast, always remember that haploid would imply a single set of chromosomes, polyploid refers to multiple sets beyond two, and euploid denotes a normal set of chromosomes, which can apply to both diploid and polyploid cells but does not specifically mark the two-set arrangement characteristic of diploidy. Therefore, the identification of the ploidy level as dip