Question

part a - the cell cycle: interphase the cell cycle is divided into two main parts: interphase and cell division. interphase is the period in which the cell is performing normal functions and not actively engaged in cell division. most of your body’s cells spend a lot of their time in interphase. before a cell can divide, what must occur during interphase? select the best answer. view available hint(s) the sister chromatids separate into chromosomes each chromatin fiber is duplicated in the nucleus the cell only performs its normal cell functions the dna relaxes into chromosomes

Explanation:

1. Analyze the first option: Sister chromatids separate into chromosomes during anaphase of mitosis (cell division phase), not interphase. So this is incorrect.
2. Analyze the second option: The cell performs normal functions during interphase, but this is not the key event required for cell division. The main preparatory event for division in interphase is DNA replication (chromatin duplication). So this is not the correct choice.
3. Analyze the third option: During interphase, specifically the S - phase (synthesis phase), the DNA (in the form of chromatin) is replicated. This means each chromatin fiber is duplicated in the nucleus. This duplication is necessary so that when the cell divides, each daughter cell gets a complete set of genetic material.
4. Analyze the fourth option: DNA relaxes into chromosomes during prophase (a phase of cell division), not interphase. In interphase, DNA is in the form of chromatin (either uncondensed or in a less condensed form as it gets ready for replication and division, but not in the highly condensed chromosome form). So this is incorrect.

Answer:

Each chromatin fiber is duplicated in the nucleus.