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Meiosis review

In the first section where it says "In female animals, three of the four meiotic products are typically eliminated by extrusion into polar bodies, and only one cell develops to produce an ovum", it should be clarified that female animals do not always create four meiotic products because the first polar body does not always divide into two. Sometimes only three meiotic products are created, two of them being polar bodies, and one being a gamete. Madelyndotson (talk) 01:57, 4 February 2017 (UTC)

For the chart explaining the Meiosis daughter cells, it may be helpful to add an equation referring to the ploidy number. MadisonAltman (talk) 15:59, 31 January 2017 (UTC)

The subsections under "Phases", "Meiosis" of the article do not make it very clear that Leptotene, Zygotene, Pachytene, Diplotene, and Diakinesis are stages of Prophase I. Making the title of the section "Phases of Meiosis" and making Leptotene, Zygotene, Pachytene, Diplotene, and Diakinesis subcategories of "Prophase I" may clarify the section.--Ekb14 (talk) 21:00, 31 January 2017 (UTC)

The sentence “This S-phase can be referred to as "premeiotic S-phase" or "meiotic S-phase.’” is not only confusing but not necessary in the introduction of this page. An15d (talk) 01:31, 3 February 2017 (UTC)

The Non-Disjunction section of this page fails to mention aneuploidy or polyploidy, fundamental errors that occur after non-disjunction. They should both be mentioned and defined. An15d (talk) 01:31, 3 February 2017 (UTC)

In the Interphase section of this page, there should be expansion on why the cells are put into the G0 phase, which is due to the to lack of nutrients, organelles and other things. Also, the checkpoint is not surpassed because of the lack of cyclin and cyclin dependent kinases, which are not activated because of the lack of nutrients. jir14b (talk) 13:51, 3 February 2017

An image of the cyclin and cyclin dependent kinase as the cell cycle progresses could be useful to understand the checkpoint that allow the cycle to continue.jir14b (talk) 13:51, 3 February 2017

Cell Division

The article states in the first paragraph that meiosis results in 12 daughter cells, when in reality each cell only produces 4 daughter cells or one in the case of a female animal. Madelyndotson (talk) 02:58, 4 February 2017 (UTC)

Leave your review & recommended changes here

“Both of these cell division cycles are used in sexually reproducing organisms at some point in their life cycle,” (wiki cell division). Consider rephrasing to: These cell division cycles are used in sexual reproduction during their lifetime.

“For simple unicellular organisms[Note 1] such as the amoeba, one cell division is equivalent to reproduction – an entire new organism is created (wiki cell division).” Can probably take out last sentence segment that says “an entire new organism is created.”

→ consider using two different pictures instead of just one that combines binary fission, mitosis, and meiosis — Preceding unsigned comment added by Anzoo789 (talk • contribs) 14:58, 26 January 2017 (UTC)

"Meiosis results in twelve haploid daughter cells by undergoing one round of DNA replication followed by two divisions: homologous chromosomes are separated in the first division, and sister chromatids are separated in the second division. Both of these cell division cycles are used in sexually reproducing organisms at some point in their life cycle, and both are believed to be present in the last eukaryotic common ancestor."

Remove from opening paragraph and make into two separate sections, one briefly explaining Mitosis and another briefly explaining Meiosis, with links to each main Wiki page for more information. Also, we need to cite a source for the information on Mitosis and Meiosis.--Ekb14 (talk) 20:51, 31 January 2017 (UTC)

There are several statements in the lead section that go into too much detail, such as "meiosis results in twelve haploid daughter cells by undergoing one round of DNA replication followed by two divisions: homologous chromosomes are separated in the first division, and sister chromatids are separated in the second division. Both of these cell division cycles are used in sexually reproducing organisms at some point in their life cycle, and both are believed to be present in the last eukaryotic common ancestor," and "for simple unicellular organisms such as the amoeba, one cell division is equivalent to reproduction – an entire new organism is created. On a larger scale, mitotic cell division can create progeny from multicellular organisms, such as plants that grow from cuttings. Mitotic cell division also enables sexually reproducing organisms to develop from the one-celled zygote, which itself was produced by meiotic cell division from gametes". --Ekb14 (talk) 20:44, 1 February 2017 (UTC)

Doesn't meiosis result in four haploid daughter cells instead of twelve haploid daughter cells? We should revise that portion. Kme14c (talk) 23:14, 1 February 2017 (UTC)

My recommended revision for a large portion of this paragraph would be --"meiosis results in four haploid daughter cells by undergoing one round of DNA replication followed by two divisions: homologous chromosomes are separated in the first division, and sister chromatids are separated in the second division. The cell divisions which occur in both meiosis and mitosis are vital to progeny created via sexual reproduction. Kme14c (talk) 23:32, 1 February 2017 (UTC)

"The primary concern of cell division is the maintenance of the original cell's genome. Before division can occur, the genomic information that is stored in chromosomes must be replicated, and the duplicated genome must be separated cleanly between cells."

This sentence should be moved earlier on in the article, at the end of the first paragraph. Also, instead of saying "the duplicated genome must be separated cleanly between cells'" it makes more sense to say that the duplicated DNA must be equivalent in each daughter cell after a division of the parent cell. Ecaber (talk) 16:28, 1 February 2017 (UTC) Ecaber

In the first paragraph, first sentence of the page, the parent cell is referred to as a parent cell right away. Seeing as someone reading this page is assumed to have no previous knowledge of the subject, it would be better to refer to it as a cell and then explain that when it is undergoing cell division it can then be called a parent cell. MadisonAltman (talk) 16:31, 1 February 2017 (UTC)

"The human body experiences about 10 quadrillion cell divisions in a lifetime.[5]" The source for this sentence is a non-science magazine and may not be reliable. Ecaber (talk) 20:30, 1 February 2017 (UTC)Ecaber

"Mitotic cell division also enables sexually reproducing organisms to develop from the one-celled zygote, which itself was produced by meiotic cell division from gametes."

Consider revising to 'After fertilization in sexually reproducing organisms, mitotic cell division allows the newly formed zygote to increase in size from a single diploid cell to a complex multicellular organism.[1]' Kme14c (talk) 23:11, 1 February 2017 (UTC)

“There are checkpoints during interphase that allow the cell to be either progressed or denied further development. If the cell does not progress through G1, the cell then enters a stage called G0. In G0, cells are still living but they are put on hold. The cells may later be called back into interphase if needed at a later time.” (cell division wiki)

To make the sentences flow better, I would suggest switching this sentence “If the cell does not progress through G1” and putting it after this one “There are checkpoints during interphase”. The sentence that explains checkpoints should come before the one about the G1 and G0 phase for better clarification. --hc13j (talk) 18:05, 1 February 2017

--I agree that this section needs alteration. However, the "flow" of sentences is not the problem. I think that more details should be added referring to the specific proteins that are involved in the control of the cell cycle. For example, Cyclin Dependent Kinase (CDK) is a very important protein involved in the check points of the cell cycle. In addition, if levels of CDK are out of normal ranges, the cell cycle can be altered in different ways such as the cell going into cell cycle arrest. This can create many different types of problems that are linked to cancer.Madelyndotson (talk) 02:58, 4 February 2017 (UTC)

“Germ cells undergo meiosis, while somatic cells will undergo mitosis.” (cell division wiki)

I would suggest taking this sentence out of the Interphase section altogether because it doesn’t really belong in this section and could cause confusion if left. --hc13j (talk) 18:07, 1 February 2017 — Preceding unsigned comment added by 68.234.254.19 (talk)

"The control of each checkpoint is controlled by cyclin and cyclin dependent kinases." (cell division wiki)

I would suggest having the sentence start with 'Each checkpoint' to avoid repeating the same word in the sentence. --hc13j (talk) 18:36, 1 February 2017 — Preceding unsigned comment added by 68.234.254.19 (talk)

I agree with you. I think this should go at the very beginning of the article. It may be helpful to begin the article with a brief overview of cell division and then break it down into subcategories highlighting the differences between meiosis and mitosis. Kme14c (talk) 23:40, 1 February 2017 (UTC)

Prophase is the first stage of division. At this point, the nuclear envelope will be broken down. Long strands of chromatin condense to form shorter more visible strands called chromosomes.[1] Chromosomes will also be visible under a microscope and will be connected at the centromere.

I would suggest changing the description to: "Prophase is the first stage of mitosis. Majority of the time during mitosis is spent during the prophase stage. During this time two pairs of centrioles will move to opposite sides of the cell all while the nuclear envelope is breaking down. As this is happening the chromatids are condensing and form into visible chromosomes, which are connected by a centromere.[1]" Akf14d (talk) 22:32, 2 February 2017 (UTC)

Metaphase is the stage in cell division when the chromosomes line up in the middle of the cell. The chromosomes are till condensing and are currently at one step away from being the most coiled and condensed they will be.[1] At this point, the chromosomes are ready to split into another cell. Spindle fibers start to form in order to begin that process.

I would suggest changing the description to: "Metaphase is the stage in cell division when the chromosomes line up in the middle of the cell along the metaphase plate. Prometaphase will be the first phase that occurs after prophase, but precedes metaphase. Prometaphase is referring to chromosome movement, while metaphase is referring to the configuration of the chromosomes after they have migrated. The spindle fibers from the centrioles then attach to the centromere, further lining the chromosomes up along the metaphase plate in an arms-out configuration. [2]" Akf14d (talk) 22:32, 2 February 2017 (UTC)

Original: "Anaphase is a very short stage of the cell cycle and occurs after the chromosomes align at the mitotic plate. After the chromosomes line up in the middle of the cell, the spindle fibers will pull them apart. The chromosomes are split apart as the sister chromatids move to opposite sides of the cell."

My Edit:Some changes I would have made to this definition would have been to mention that anaphase is the shortest stage of Mitosis. Another big part that is left out is mentioning that when the sister chromatids separate, that this is called disjunction.Codyboswell9 (talk) 22:51, 2 February 2017 (UTC)

Orginal: "Telophase is the last stage of the cell cycle. Two cells form around the chromatin at the two poles of the cell. Two nuclear membranes begin to reform and the chromatin begin to unwind."

My Edit: The biggest change I would make to the Telophase part would be to mention Cytokinesis. This part of telophase is very important because for two new cells to become one, you must have cytokinesis.Codyboswell9 (talk) 22:51, 2 February 2017 (UTC)

I certainly agree, I think that there should be a mention of cytokinesis because it is essential to telophase. Additionally, I think it would be insightful to further elaborate on telophase as a whole, for it is the least described among each phase outlined. I suggest including how the nuclear membranes form to separate DNA from the cytoplasm, cytokinesis divides the cytoplasm to form two daughter cells, and also clarifying that this phase results in the duplicated genetic material from a parent cell being separated into two identical daughter cells. Csc14c (talk) 22:47, 30 April 2017 (UTC)

At the end of the cell division, chromosomes are extremely moist. The moisture on the chromosome is seen to serve as protection. It prevents the chromosome from having any difficulty or issue when they are intended to split. To try and see if it was in fact the moisture serving as protection for the chromosomes, researchers have taken a cell, added chemicals that intentionally block the cells ability to perspire or become moist, and several issue or defects came into sight. </ref> Dml16h (talk) 01:23, 3 February 2017 (UTC)

The summary section needs to be reorganized. Starting with the mention of fission.

Prokaryotes undergo a vegetative cell division known as binary fission, where their genetic material is segregated equally into two daughter cells. All cell divisions, regardless of organism, are preceded by a single round of DNA replication.

For simple unicellular organisms[Note 1] such as the amoeba, one cell division is equivalent to reproduction – an entire new organism is created.

Binary fission should be in its own paragraph with a better organization, these two sentences should be in the same paragraph and should also mention that fission also occurs in some organelles, such as mitochondria. Kpartynski (talk)

Under the "Phases of cell division" are there should also be a section for binary fission that explains the 4 types of fission.

Prophase is the first stage of division. At this point, the nuclear envelope will be broken down. Long strands of chromatin condense to form shorter more visible strands called chromosomes.[6] Chromosomes will also be visible under a microscope and will be connected at the centromere.

This section completely ignores that meiosis 1 prophase one there are many important stages; leptotene, zygotene, pachytene, etc. meiosis. Kpartynski (talk)

The interphase section needed to be added because nothing was said of this important stage and I wrote this and submitted it Cmg14n (talk) 02:24, 3 February 2017 (UTC)

I have attached the draft of my interphase section which was submitted to the wiki page: Interphase is the process a cell must go through before mitosis, meiosis, and cytokinesis.[5] Interphase consists of four main stages: G1, S, G2, and M. G1 is a time of growth for the cell. If the cell does not progress through G1, the cell then enters a stage called G0. In G0, cells are still living but they are put on hold. The cells may later be called back into interphase if needed at a later time. There are checkpoints during interphase that allow the cell to be either progressed or denied further development. In S phase, the chromosomes are replicated in order for the genetic content to be maintained. During G2, the cell undergoes the final stages of growth before it enters the M phase. The M phase, can be either mitosis or meiosis depending on the type of cell. Germ cells undergo meiosis, while somatic cells will undergo mitosis. After the cell proceeds through successfully through the M phase, it may then undergo cell division through cytokinesis. The control of each checkpoint is controlled by cyclin and cyclin dependent kinases. The progression of interphase it the result of the increased amount of cyclin. As the amount of cyclin increases, more and more cyclin dependent kinases attach to cyclin signaling the cell further into interphase. The peak of the cyclin attached to the cyclin dependent kinases this system pushes the cell out of interphase and into the M phase, where mitosis, meiosis, and cytokinesis occur.Cmg14n (talk) 02:34, 3 February 2017 (UTC)

It would also be helpful to include animations at each stage of cell division. These animations can help visualize the information to make the concepts easier to grasp for visual learners. There should also be more detailed information about the chromosomes at each stage. Along with the multiple sub stages in prophase. Another talking point could be how the cell responds to different things that go wrong in the cell. For example, causes that could lead to cancer. This will show how important maintenance of cell division is. In the telophase section i would add information about the pinching go the cell membranes that form the new cells. There should also be two different subsections for mitosis and meiosis. The meiosis section should explain how the spermatogonium or oogonium undergoes division into both primary, secondary, and finally mature into spermatozoa and/ or an ovum. Cmg14n (talk) 02:40, 3 February 2017 (UTC)

Telophase subsection This section of the cell division page is very underdeveloped along with the prophase, anaphase, and metaphase section. I suggest that we add a description of cytokinesis to telophase. “Cytokinesis is a part of the cell cycle where the cell divides into two separate daughter cells. The cytoplasm separates while the sister chromatids are at opposite ends of the cell. Cytokinesis is a very important process and needs to be timed correctly. Luke Kendall (talk) 03:12, 3 February 2017 (UTC)

Interphase section

An image depicting the stages of interphase should be added in order to enhance the audience's comprehension. "Interphase is the process a cell must go through before mitosis, meiosis, and cytokinesis." (wiki cell division). Perhaps change this to "Interphase is the first stage of cell division. A cell must undergo interphase before entering mitosis/meiosis and cytokinesis.

"The human body experiences about 10 quadrillion cell divisions in a lifetime." (Wiki cell division). I do not think that this is necessary.

Minhtyy (talk) 04:01, 3 February 2017 (UTC)

Telophase section I second the fact that this section is for the majority underdeveloped and should be strengthened with mention of the reformation of the nuclear envelope. This being the final stage of cell division, there should also be mention of cytokinesis and its relevence to the final stage of cell division. Adding a single diagram to each of these phases would significantly improve the level of understanding to whomever is reading this section, especially if the individual is somewhat new to the subject matter. Jad15e (talk) 01:38, 4 February 2017 (UTC)

Zygotene Section

Under the description of zygote it states that it is more of an exact alignment and highly specific for synapsis of the homologous chromosomes occurs. After looking up zygotene, it states that the synapsis occurs at various locations on the chromosomes. Melissa6496 (talk) 18:36, 8 February 2017 (UTC)Mnm16d

Meiosis Edit (ar15ac)

In the introduction of meiosis the small edit I made of including information about the individual pair of sex specific chromosomes included in the 23 pairs of total human chromosomes (...including 1 pair of sex chromosomes...) is highlighted in bold.

Meiosis Listeni/maɪˈoʊsᵻs/ is a specialized type of cell division that reduces the chromosome number by half, creating four haploid cells, each genetically distinct from the parent cell that gave rise to them.[1] This process occurs in all sexually reproducing single-celled and multicellular eukaryotes, including animals, plants, and fungi.[2][3][4][5] Errors in meiosis resulting in aneuploidy are the leading known cause of miscarriage and the most frequent genetic cause of developmental disabilities.[6]

In meiosis, DNA replication is followed by two rounds of cell division to produce four potential daughter cells, each with half the number of chromosomes as the original parent cell. The two meiotic divisions are known as Meiosis I and Meiosis II. Before meiosis begins, during S phase of the cell cycle, the DNA of each chromosome is replicated so that it consists of two identical sister chromatids, which remain held together through sister chromatid cohesion. This S-phase can be referred to as "premeiotic S-phase" or "meiotic S-phase." Immediately following DNA replication, meiotic cells enter a prolonged G2-like stage known as meiotic prophase. During this time, homologous chromosomes pair with each other and undergo genetic recombination, a programmed process in which DNA is cut and then repaired, which allows them to exchange some of their genetic information. A subset of recombination events results in crossovers, which create physical links known as chiasmata (singular: chiasma, for the Greek letter Chi (X)) between the homologous chromosomes. In most organisms, these links are essential to direct each pair of homologous chromosomes to segregate away from each other during Meiosis I, resulting in two haploid cells that have half the number of chromosomes as the parent cell. During Meiosis II, the cohesion between sister chromatids is released and they segregate from one another, as during mitosis. In some cases all four of the meiotic products form gametes such as sperm, spores, or pollen. In female animals, three of the four meiotic products are typically eliminated by extrusion into polar bodies, and only one cell develops to produce an ovum.

Because the number of chromosomes is halved during meiosis, gametes can fuse (i.e. fertilization) to form a diploid zygote that contains two copies of each chromosome, one from each parent. Thus, alternating cycles of meiosis and fertilization enable sexual reproduction, with successive generations maintaining the same number of chromosomes. For example, diploid human cells contain 23 pairs of chromosomes including 1 pair of sex chromosomes (46 total), half of maternal origin and half of paternal origin. Meiosis produces haploid gametes (ova or sperm) that contain one set of 23 chromosomes. When two gametes (an egg and a sperm) fuse, the resulting zygote is once again diploid, with the mother and father each contributing 23 chromosomes. This same pattern, but not the same number of chromosomes, occurs in all organisms that utilize meiosis. — Preceding unsigned comment added by Ar15ac (talk • contribs) 18:51, 25 February 2017 (UTC)

All encompassing edit

I believe that the fusion of text and illustrations/animations allows for a more thorough understanding of subject material, especially concerning this particular topic. I think that it would be beneficial to add a simple, single image to each phase of cell division described in the article (interphase, prophase, metaphase, anaphase, telophase) illustrating what is being detailed. Furthermore, I think that a youtube video which summarizes mitosis could be placed at the end of the phase descriptions as a recap for the reader. These visual additions combined with the text would serve to provide a more comprehensible and cohesive article for the audience to read and learn from. Csc14c (talk) 23:15, 30 April 2017 (UTC)