Final answer:
The loose strands of DNA that appear grainy when the cell is not dividing are referred to as chromatin. Chromatin exists in this state during interphase, but will condense into chromosomes, consisting of sister chromatids joined at a centromere, when the cell is preparing for division.
Step-by-step explanation:
When the cell is not dividing, the loose strands of DNA appear grainy and are referred to as chromatin. The term chromatin refers to the material in eukaryotic cells, which consists of DNA, RNA, and protein, and is located within the nucleus. This grainy and loosely coiled form of DNA can be found in the cell during the interphase—a period between cell divisions—when the cell is not actively dividing. Upon entering cell division, the chromatin becomes more tightly coiled and condenses into chromosomes, each consisting of two sister chromatids joined at a centromere. Chromatids and chromosomes are terms related to the cell division process, while nucleosomes are DNA-wrapped histone complexes that carry the structure of chromatin.