Question

30 баллов назовите и охарактеризуйте фазы митоза.

Answer 1

1 профаза - тут хромосомы скручиваются , разрывается ядерная оболочка и расходятся центриоли
2)метафаза выстраивание хромосом к экватору
3) анофаза расхождение сестринских хроматин
4) телофаза достижение хромосом полюсов , формирования ядерной оболочки

Answer 2

The Phases of Mitosis

Mitosis is the process of cell division that results in the formation of two identical daughter cells. It consists of several distinct phases, each with its own characteristics. Here are the phases of mitosis:

1. Interphase: Interphase is not technically a phase of mitosis, but it is the period of cell growth and preparation for division. During interphase, the cell undergoes normal metabolic activities and duplicates its DNA in preparation for division. Interphase can be further divided into three subphases: G1 (Gap 1), S (Synthesis), and G2 (Gap 2).

2. Prophase: Prophase is the first phase of mitosis. During prophase, the chromatin condenses into visible chromosomes, and the nuclear membrane starts to break down. The centrosomes move to opposite poles of the cell, and spindle fibers begin to form.

3. Prometaphase: Prometaphase is a transitional phase between prophase and metaphase. During prometaphase, the nuclear membrane completely disintegrates, and the spindle fibers attach to the kinetochores, which are protein structures on the centromeres of the chromosomes.

4. Metaphase: Metaphase is the phase of mitosis where the chromosomes align along the equatorial plane of the cell, known as the metaphase plate. The spindle fibers attach to the kinetochores of the chromosomes, ensuring that each chromosome is properly aligned for separation.

5. Anaphase: Anaphase is the phase in which the sister chromatids separate and move towards opposite poles of the cell. The spindle fibers shorten, pulling the chromatids apart. At the end of anaphase, each pole of the cell has a complete set of chromosomes.

6. Telophase: Telophase is the final phase of mitosis. During telophase, the chromosomes reach the opposite poles of the cell, and the spindle fibers disassemble. The nuclear membrane reforms around each set of chromosomes, and the chromosomes begin to decondense back into chromatin.

7. Cytokinesis: Cytokinesis is the process of dividing the cytoplasm and organelles between the two daughter cells. In animal cells, a cleavage furrow forms and deepens until the cell is pinched in two. In plant cells, a cell plate forms in the middle of the cell and gradually develops into a new cell wall.

These are the main phases of mitosis, each with its own distinct characteristics and events. It is important to note that the duration of each phase can vary depending on the cell type and other factors.