Prophase (Prophase)

Prophase is the first and longest stage of mitosis and meiosis, during which chromosomes are prepared for separation. At this stage, chromosomes become visible under a microscope due to their condensation, which helps them hold on to their genes during cell division.

The first prophase of meiosis consists of five stages: leptotene, zygotene, pachytene, diplotene and diakinesis. During the leptotene stage, long strands of DNA begin to fold into shorter, denser chromosomes. Then comes the zygotene stage, in which the chromosomes begin to form pairs called bivalents. These pairs are formed through a process called synapsis, in which the exchange of material between chromosomes can occur.

After zygotene comes the pachytene stage, during which cross-exchange of genetic material between chromosomes occurs, which increases the genetic diversity of the offspring. At the diplotene stage, the chromosomes separate but remain connected at the points of material exchange. Finally, during the diakinesis stage, chromosomes continue to condense and prepare to separate.

In prophase, centrioles also split, which move to opposite poles of the cell and form the mitotic apparatus. This apparatus consists of microtubules that will be used to move chromosomes during cell division.

In general, prophase is an important stage of cell division that prepares chromosomes for separation and ensures the correct division of genetic material between daughter cells. It also plays an important role in the exchange of genetic material between chromosomes, which increases the genetic diversity of offspring.

Prophase is the first stage of mitosis, which is also the first stage of each meiotic division. During prophase, chromosomes take on a noticeable shape and become visible under a microscope, allowing you to see their structure and location in the cell.

During prophase, a number of changes occur in the structure of the cell that prepare it for division. The cells begin to divide into two daughter cells, each of which will have its own genetic information.

In prophase of meiosis, the first stage consists of five stages:

1. Leptotene - At this stage, the chromosomes begin to stretch out and become distinguishable.
2. Zygotene - chromosomes stretch even more and come closer together, forming pairs.
3. Pachyten - thickening of chromosomes occurs, which become more noticeable.
4. Diplotena - At this stage, the chromosomes are completely separated, forming two separate strands.
5. Diakinesis - This is the last stage of prophase when the chromosomes align and become ready to separate.

Each stage of prophase has its own characteristics and functions that help prepare the cell for further division and the formation of new cells.

**Prophase** (from the Greek πρό - before Φα/ς - before, phase/ “beginning” + prefix ἀ-, meaning negation or removal; lat. pro phasis - pre-initial) - one of the stages of cell division, before the middle of the phase is in interkinesis, precedes the metaphase of mitosis and the prophase of the first division of meiosis.

Currently, the terms “prophase” and “latent stage” are used primarily to refer to the various stages of development of germ cells (sperm and eggs) in the human body and other mammals. In everyday use, the term "prophase" can also be used to describe the process of formation of raw bread dough. _Prophases in neuroglia._ Some features occur in gonadal and nervous tissues, for example, in some tumors (for example, leydigoma, choriocarcinoma), tumor T-lymphocytes, as well as in mature leukemia cells after chemotherapy. An important diagnostic feature is the presence of small vesicles or isolated nuclei in multinucleated cells of “irregular shape”, consisting of large hyaloplastic basophilic eosinophilic nuclei of irregular shape, varying in size. This phenomenon is called parachylia. This corresponds to the phase of the parachyl nuclear complex (latent - latent).