Question

Put the following steps of the cell cycle in order from 1 to 4:

- Cytoplasm splits (cytokinesis)
- Spindle fibers form
- Centromere breaking and sister chromatids separating
- S phase of interphase

Answer 1

The cell cycle steps in the correct order are: S phase of interphase, spindle fiber formation, centromere breaking and sister chromatids separating, and finally, cytoplasm splitting (cytokinesis).

Step-by-step explanation:

The correct sequence of events for the cell cycle is as follows:

1. S phase of interphase
2. Spindle fibers form
3. Centromere breaking and sister chromatids separating
4. Cytoplasm splits (cytokinesis)

During the S phase of interphase, the cell synthesizes a complete copy of the DNA in its nucleus in preparation for cell division. This phase is crucial for ensuring that each new cell will have a full set of chromosomes. As the cell progresses into mitosis, spindle fibers begin to form, stemming from the centrosomes, which have begun to move apart towards the poles of the cell. During metaphase, the chromosomes align at the cell's equator and spindle fibers attach to the centromeres. During anaphase, the centromeres break allowing sister chromatids to separate and move to opposite poles of the cell. Finally, during telophase and cytokinesis, the spindle breaks down, new nuclear membranes form around each set of chromosomes, and the cytoplasm splits, resulting in two distinct daughter cells.