Question

Опишите процесс деления клетки

Answer 1

Деление клетки — характерный именно для живых организмов процесс появления из родительской клетки двух и более новых клеток.

Answer 2

The Process of Cell Division

Cell division is the process by which a parent cell divides into two or more daughter cells. This process is essential for growth, development, and the maintenance of multicellular organisms. There are two main types of cell division: mitosis and meiosis.

Mitosis is the type of cell division that occurs in somatic cells, which are non-reproductive cells. It is responsible for the growth and repair of tissues, as well as the production of identical daughter cells. The process of mitosis can be divided into several stages:

1. Interphase: This is the phase before cell division where the cell prepares for division. During interphase, the cell grows, carries out its normal functions, and duplicates its DNA.

2. Prophase: In this stage, the chromatin (loosely packed DNA) condenses into visible chromosomes. The nuclear membrane also breaks down, and the centrosomes move to opposite poles of the cell.

3. Metaphase: The chromosomes line up along the equator of the cell, forming a structure called the metaphase plate. The centrosomes release spindle fibers that attach to the centromeres of the chromosomes.

4. Anaphase: The spindle fibers contract, pulling the sister chromatids apart. Each chromatid, now called a chromosome, moves towards opposite poles of the cell.

5. Telophase: The chromosomes reach the opposite poles of the cell, and a new nuclear membrane forms around each set of chromosomes. The chromosomes begin to decondense, and the cell starts to divide.

6. Cytokinesis: This is the final stage of cell division, where the cytoplasm divides, and two daughter cells are formed. In animal cells, a cleavage furrow forms, pinching the cell in two. In plant cells, a cell plate forms in the middle of the cell, eventually becoming a new cell wall.

Meiosis is a specialized type of cell division that occurs in reproductive cells (gametes) and is involved in sexual reproduction. It involves two rounds of division, resulting in the production of four daughter cells with half the number of chromosomes as the parent cell. Meiosis is important for genetic diversity and the formation of haploid cells.

1. Meiosis I: This is the first round of division in meiosis. It consists of prophase I, metaphase I, anaphase I, and telophase I. During prophase I, homologous chromosomes pair up and exchange genetic material in a process called crossing over. In metaphase I, the homologous pairs line up along the metaphase plate. In anaphase I, the homologous chromosomes separate and move to opposite poles. In telophase I, the chromosomes reach the poles, and the cell starts to divide.

2. Meiosis II: This is the second round of division in meiosis. It is similar to mitosis and consists of prophase II, metaphase II, anaphase II, and telophase II. The sister chromatids separate in anaphase II, resulting in four haploid daughter cells.

Overall, cell division is a highly regulated and complex process that ensures the proper distribution of genetic material and the formation of new cells. It plays a crucial role in the growth, development, and reproduction of organisms.