Biology MYA Complete Practice Test 2026 – Prepare for Your Exam

During interphase, DNA exists in a loosely packed form called chromatin. This relaxed arrangement, made of DNA wrapped around histone proteins into nucleosomes, allows the cell to read and copy genetic information, enabling transcription and DNA replication to occur efficiently. As cells enter mitosis, chromatin condenses into tightly packed chromosomes so they can be evenly separated into daughter cells. The other terms refer to different structures: a chromosome is a highly condensed form seen during mitosis; a chromatid is one of the two identical copies of a replicated chromosome; and a centromere is the region where sister chromatids are held together and where spindle fibers attach during separation.