#Describe prophase code

The other phases of meiosis – metaphase, anaphase, and telophase – are just as important to the creation of gametes as prophase. While prophase, as described above, is the initial phase in both rounds of cellular division, prophase is just one part of a larger, complex process that creates gametes/sex cells. Photo: By Rdbickel – Own work, CC BY-SA 4.0, After crossing over occurs, the cell proceeds into metaphase I. The combinations of genes in the chromosomes are changed due to this process, and the areas where crossing over occurs is essentially random.

#Describe prophase code

Another way to think about this is imagining the two chromosomes of each homolog pair oriented parallel to the other chromosome pair, and bits of the genetic code being pulled out one chromosome and stitched into the respective part of the other chromosome. This process of association is referred to as “synapsing” and through this process, the homolog pairs form a larger structure referred to as a “tetrad”.ĭuring synapsis, the two chromosomes of the respective homolog pairs exchange chunks of their DNA strands/swap parts of their genome. During prophase I, the two members of each homolog pair in a sex cell become linked to one another along the entire length of the chromosome. Throughout most of the meiosis process, ending in metaphase II, the sister chromatids stay attached to one another, bound at the centromere. The spindle fibers eventually extend all the way, moving the centrosomes to opposing ends of the cell, the poles.Įach of the chromosomes found within the cell at this point are made out of two sister chromatids, and these chromatids have genetic information that is identical. The spindle apparatus is created by long spindle fibers that extend from the two centrosomes within the cell.

The nucleolus, the smaller organelle within the nucleus, disappears as well. The nuclear envelope, the structure that surrounds the nucleus, breaks up, vanishing. This makes the chromosomes visible under a light microscope. This means that during prophase I, the chromosomes condense, becoming thicker and shorter. What happens during prophase I of meiosis? What Happens During Prophase I?īy the time prophase I of meiosis begins, the chromosomes within the cell have duplicated and prepared for cellular division. However, unlike mitosis, meiosis goes through two round of cellular division, so there is prophase I and prophase II, metaphase I and metaphase II, etc. Meiosis creates daughter cells that possess half as many chromosomes as the parent cell, and meiosis proceeds through four different phases, just like mitosis does: prophase, metaphase, anaphase, and telophase. Mitosis is the process that creates new daughter cells from the original parent cells, while meiosisis a similar process that creates just one type of cell – sex cells, or gametes. See more at meiosis mitosis.The human body needs to create new cells to replace old, worn out ones. If a membrane has formed around the chromosomes at the end of the first division, it disappears during prophase II.

During prophase II, the individual chromosomes of the daughter cells become distinct again and begin to prepare for the second meiotic division. At the beginning of prophase II of meiosis, which occurs after telophase during the first meiotic division, the chromosomes of each daughter cell are grouped together in a mass. In mitosis, by contrast, pairs of homologous chromosomes remain separate and there is no crossing over, since the purpose of mitosis is to produce cells with identical genetic material rather than gametes.

This process creates genetic diversity among the gametes formed through meiosis. In prophase I of meiosis, pairs of homologous chromosomes intertwine and the process called crossing over occurs as chromatids from homologous pairs of chromosomes swap genetic information. The prophase of meiosis occurring during the first meiotic division of the cell is usually called prophase I. However, there are important distinctions between prophase of mitosis and prophase of meiosis. One of the two stages in meiosis that resemble prophase in mitosis.