Question
Steps of mitosis
Answers
GPT-4o mini
Mitosis is the process by which a eukaryotic cell divides its nucleus and cytoplasm to produce two genetically identical daughter cells. Mitosis is typically divided into several distinct phases:
1. **Prophase**:
- Chromatin condenses into visible chromosomes, each consisting of two sister chromatids joined at the centromere.
- The nuclear envelope begins to break down.
- The mitotic spindle, composed of microtubules, starts to form and extends from the centrosomes, which move to opposite poles of the cell.
2. **Metaphase**:
- Chromosomes align at the metaphase plate, an imaginary line equidistant from the spindle poles.
- Kinetochores (protein structures on the centromeres) attach to microtubules from opposite spindle poles.
- The alignment ensures that each daughter cell will receive one copy of each chromosome.
3. **Anaphase**:
- The sister chromatids are pulled apart as the centromeres split, and the spindle fibers shorten, moving the separated chromatids (now individual chromosomes) toward opposite poles of the cell.
- The cell begins elongating as the non-kinetochore microtubules lengthen.
4. **Telophase**:
- The separated chromosomes arrive at the opposite poles of the cell and begin to decondense back into chromatin.
- The nuclear envelope re-forms around each set of chromosomes, resulting in two nuclei within the cell.
- The mitotic spindle disassembles.
5. **Cytokinesis** (though not technically a phase of mitosis, it usually occurs concurrently with telophase):
- The cytoplasm divides, creating two distinct daughter cells.
- In animal cells, this is accomplished through the formation of a cleavage furrow that pinches the cell in two. In plant cells, a cell plate forms along the center of the cell, eventually developing into a new cell wall.
These steps ensure that the genetic material is accurately replicated and equally distributed, vital for growth, repair, and maintenance of an organism.
1. **Prophase**:
- Chromatin condenses into visible chromosomes, each consisting of two sister chromatids joined at the centromere.
- The nuclear envelope begins to break down.
- The mitotic spindle, composed of microtubules, starts to form and extends from the centrosomes, which move to opposite poles of the cell.
2. **Metaphase**:
- Chromosomes align at the metaphase plate, an imaginary line equidistant from the spindle poles.
- Kinetochores (protein structures on the centromeres) attach to microtubules from opposite spindle poles.
- The alignment ensures that each daughter cell will receive one copy of each chromosome.
3. **Anaphase**:
- The sister chromatids are pulled apart as the centromeres split, and the spindle fibers shorten, moving the separated chromatids (now individual chromosomes) toward opposite poles of the cell.
- The cell begins elongating as the non-kinetochore microtubules lengthen.
4. **Telophase**:
- The separated chromosomes arrive at the opposite poles of the cell and begin to decondense back into chromatin.
- The nuclear envelope re-forms around each set of chromosomes, resulting in two nuclei within the cell.
- The mitotic spindle disassembles.
5. **Cytokinesis** (though not technically a phase of mitosis, it usually occurs concurrently with telophase):
- The cytoplasm divides, creating two distinct daughter cells.
- In animal cells, this is accomplished through the formation of a cleavage furrow that pinches the cell in two. In plant cells, a cell plate forms along the center of the cell, eventually developing into a new cell wall.
These steps ensure that the genetic material is accurately replicated and equally distributed, vital for growth, repair, and maintenance of an organism.