1. DNA Replication:
* Precise Copying: Before cell division, the entire genome is duplicated in a process called DNA replication. This ensures that each new cell receives a complete set of chromosomes.
* Semiconservative Replication: Each new DNA molecule consists of one original strand and one newly synthesized strand, ensuring accuracy and minimizing errors.
2. Chromosome Condensation:
* Organization and Separation: During cell division, the replicated chromosomes condense into compact structures, making them easier to separate and distribute to daughter cells.
3. Mitotic Spindle Formation:
* Microtubule Network: A specialized structure called the mitotic spindle, made of microtubules, forms within the cell. Microtubules attach to the chromosomes at specific points called kinetochores.
* Chromosome Movement: Microtubules shorten and lengthen, pulling the replicated chromosomes apart to opposite poles of the cell.
4. Cytokinesis:
* Division of Cytoplasm: After chromosomes have been separated, the cell's cytoplasm divides, forming two distinct daughter cells. This process is called cytokinesis.
5. Cell Cycle Checkpoints:
* Quality Control: The cell cycle has checkpoints that ensure DNA is replicated accurately and the chromosomes are properly aligned before the cell divides. This helps prevent errors in chromosome segregation.
6. Sister Chromatid Cohesion:
* Holding Together: During replication, sister chromatids (identical copies of each chromosome) are held together by proteins called cohesins. This ensures that the sister chromatids remain attached until they are ready to be pulled apart during mitosis.
7. DNA Repair Mechanisms:
* Error Correction: DNA repair mechanisms are constantly working to correct any errors that may occur during DNA replication, further ensuring the accuracy of chromosome duplication.
Together, these processes ensure that each new eukaryotic cell receives a complete and accurate copy of the genetic information contained within its chromosomes.
