What is mitosis and what process occurs in prophase mitosis?

What is mitosis and meiosis and what phases do they have? This is a cell division that has some differences. With meiosis, four daughter ones are formed from the mother nucleus, in which the number of chromosomes is reduced (by half). With mitosis, cell division also occurs , but with this type only two daughter cells with the same chromosomes are formed, as in parents.

So what is mitosis and meiosis? These are biological division procedures during which cells with certain chromosomes are formed. Reproduction by mitosis occurs in multicellular, complex living organisms.

Stages

Mitosis proceeds in two stages:

1. Doubling information at the gene level. Here, maternal cells distribute genetic information among themselves. At this stage, the chromosomes change.
2. Mitotic stage. It consists of time periods.

Cellular formation occurs in several stages.

Phases

Mitosis is divided into several phases:

• telophase;
• anaphase;
• metaphase;
• prophase.

These phases proceed in a certain sequence and have their own characteristics.

In any complex multicellular mitosis, it most often implies cell division by an undifferentiated type. In mitosis, the mother cell is divided into daughter cells, usually two of them. One of them becomes a stem and continues to divide, and the second ceases to divide.

Interphase

Interphase is a cellular preparation for separation. Usually this stage lasts up to twenty hours. At this time, many different processes take place, during which the cells prepare for mitosis.

During this period, protein division occurs, the number of organelles in the DNA structure increases. By the end of division, genetic molecules double, and the number of chromosomes does not change. Identical DNAs are spliced ​​and are two chromatids in one molecule. The resulting chromatids are identical and sister.

After completion of the interphase, mitosis proper begins. It consists of prophase, metaphase, anaphase and telophase.

Prophase

The first phase of mitosis is prophase. It lasts about an hour. It is conditionally divided into several stages. At the initial stage, in the prophase of mitosis, an increase in the nucleolus occurs, as a result of which molecules are formed. By the end of the phase, each chromosome already consists of two chromatids. Nuclei and nuclear membranes dissolve, all elements are in a cell in a mess. Further, in the prophase of mitosis, the formation of achromatin division occurs, some of the threads pass through the entire cell, and some are connected to the central elements. In this process, the content of the genetic code remains unchanged.

The number of chromosomes in the prophase of mitosis does not change. What else is happening? In the prophase of mitosis, the nuclear membrane decays, as a result of which the spiral chromosomes end up in the cytoplasm. Particles of a decayed nuclear envelope form small membrane vesicles.

In the prophase of mitosis, the following occurs: the cell of the animal becomes round, but in plants it does not change shape.

Metaphase

After prophase, metaphase occurs. In this phase, chromosome helixation reaches its peak. Shortened chromosomes begin to move toward the center of the cell. During movement, they are located equally in both parts. A metaphase plate is formed here. When looking at cells, chromosomes are clearly visible. It is in metaphase that they are easy to count.

After the formation of the metaphase plate, an analysis of the set of chromosomes inherent in this type of cell is carried out. This occurs by blocking chromosome discrepancies using alkaloids.

Each organism has its own set of chromosomes. For example, corn has 20, and garden strawberries have 56. In the human body, there are fewer chromosomes than berries, only 46.

Anaphase

All processes occurring in the prophase of mitosis end and anaphase begins. During this process, all chromosomal compounds are broken and begin to move in opposite directions from each other. In anaphase, related chromosomes become independent. They enter various cells.

The phase ends with a divergence to the poles of the chromatid cell. Also here is the distribution of hereditary information between the daughter and the mother cell.

Telophase

Chromosomes are located at the poles. Under a microscope, they become poorly visible, since a core shell is formed around them. The spindle of division is completely destroyed.

In plants, the membrane forms in the center of the cell, gradually spreading to the poles. She divides the mother cell into two parts. As soon as the membrane has fully grown, a cellulose wall appears.

Features of mitosis

Cell division can be inhibited due to high temperatures, exposure to poisons, radiation. During the study of cell mitosis in different multicellular organisms, poisons can be used that inhibit mitosis at the metaphase stage. This allows you to study chromosomes in detail, to carry out karyotoping.

Mitosis on the table

Consider the phases of cell division in the table below.

The process of stages of mitosis can also be seen in the table.

Mitosis in animals and plants

Features of this process can be described in the comparative table.

So, we considered the process of cell division in animal organisms and plants, as well as their features and differences.