Answer
Correct Option:
(1) To separate the chromosomes
Detailed Explanation:
During mitosis, spindle fibers play a crucial role in the accurate segregation of chromosomes to the daughter cells. This ensures that each new cell receives an identical set of chromosomes.
Role of Spindle Fibers:
- Spindle fibers are microtubule structures originating from centrosomes.
- They attach to kinetochores, which are protein complexes on the centromere.
- During anaphase, the spindle fibers shorten and pull the sister chromatids apart.
- These chromatids, now individual daughter chromosomes, move to opposite poles of the cell.
Supporting Information:
Kinetochores serve as the attachment points for spindle fibers. At the onset of anaphase, chromosomes split and daughter chromatids migrate toward the opposite poles, aided by the dynamic behavior of spindle fibers.
Summary:
Spindle fibers ensure the proper distribution of chromosomes, which is critical for maintaining genetic stability in cell division. Therefore, their primary function is to separate the chromosomes.
Why Other Options Are Incorrect:
- (2) To synthesize new DNA: DNA synthesis happens during the S phase, not during mitosis.
- (3) To repair damaged DNA: DNA repair occurs at various stages, but is not the main role of spindle fibers.
- (4) To regulate cell growth: Cell growth is governed by checkpoints and signaling, not spindle fibers.