Mitosis is a term for describing cellular replication in eukaryotic species. Eukaryotic means that the cellular structure contains a nucleus that houses the single complete DNA genome, which contains the definition of the cell, itself. The DNA always remains within the nucleus, no matter what the cellular activity.
During the past 8 months, the people of the world have been broadsided by a highly-coordinated perpetration of fraud and global violations of the law by the very institutions charged with making these laws. The scale and scope of the scamdemic is staggering.
At this point, you may be thinking – “Why do I need to know this?”. Most citizens are never educated on this subject, which involves viruses, yet they are being controlled in this era, by a narrative dispensed by talking heads who claim to be government ‘experts’, spewing numerical statistics about a deadly virus, and then employing totally ‘over the top’ coercive protocols that, themselves, are deadly and destructive of life as the solution to this purported problem. To just panic, and accept the party line is nothing less than adopting a dogmatic new religion. People who dogmatically accept this scenario are endangering themselves, their families, friends, and their very existence based on ignorance and the belief that they are powerless to know and understand the nature of this alleged menace, and to take their own appropriate actions in response.
Please read on if you wish to understand more about this needless disaster of human creation.
Why Do Cells Need to Replicate?
Cells are similar but not identical. In fact, there is a great deal of specialization of cellular functions in complex animals. Over the course of performing its function, the cell undergoes a certain amount of wear and tear due to protein structure breakdowns, and, depending on the function being performed by the numerous and various cell types, the operational duty-cycle varies, from a matter of days to years.
The oldest cells in a human body are the bones, which can have a duty cycle of up to 15 years. Therefore, the oldest cell in an individual human body is about 15 years. Many other cells, like those of the gastric system have a duty-cycle measured in days. The individual cells have the schedule for replacing themselves prior to the point where failure to do so would result in failing or faulty function.
The process by which replication occurs is called ‘mitosis’, a part of what is called the ‘Cell cycle”.
Since the DNA, containing the codon for making an identical copy of itself, remains reclusively in the nucleus at all times, the cell has a device called mRNA, Messenger Ribose Nucleic Acid, that can pass through the nuclear membrane bearing various coding aspects of DNA components. There are two other types of RNA, but to keep this discussion from getting too technical and lengthy, this essay will not involve itself with unnecessary detail, much of which is not fully understood by science at this time anyway. The mRNA has many duties and hundreds or thousands are involved in the process of mitosis, as well as other transcriptions.
Even though the body is comprised of trillions of cells, each one is unimaginably complex, comprised of hundreds of trillions of atoms. One of the essential functions of the cell is to assemble hundreds of thousands of different proteins to supply building blocks for numerous other functions of the cell. How can a cell perform its massive work load with such precision and speed, using inert atoms from the nutrient stream? You can explore this by reading the essay on Metaphysics, which can be selected from the archive list of this site.
Eukaryotic Cells are Diploid
Eukaryotes are diploid, which means they have two sets of chromosomes; one set of chromosomes is inherited from each parent. Eukaryotic DNA is enclosed by a nuclear envelope. The proper sorting and distribution of multiple chromosomes during cell division is a complex process that requires the temporary dissolution of the nuclear envelope. Eukaryotic organisms carry out mitosis throughout their entire life to replace old or damaged cells. The daughter cells produced by mitosis are diploid and genetically identical to each other and the parent cells that produced them.
CELL CYCLE = INTERPHASE + MITOSIS
Cells only spend a small part of their life dividing. The time between consecutive mitotic divisions is referred to as interphase. Eukaryotic cells spend most of their time in interphase.
During interphase the cell’s genetic material is in the form of chromatin (uncoiled DNA), nucleoli are present, and the nuclear envelope is clearly visible. Shortly before mitosis, the cell duplicates its DNA during the S (synthesis) phase of interphase.
Mitosis can be divided into four distinct phases:
- Prophase: Nuclear envelope and nucleoli disappear. Chromatin condenses into chromosomes, which are made up of two identical sister chromatids joined by a centromere. In animal cells, centrioles start migrating to opposite ends of the cell (centrioles are not present in plant cells). The mitotic spindle forms and begins to move chromosomes towards the center of the cell.
- Metaphase: Brief stage in which chromosomes line up in the equatorial plane of the cell. In animal cells, one pair of centrioles are visible at both ends of the cell. The mitotic spindle is fully formed.
- Anaphase: Sister chromatids begin to separate, becoming individual chromosomes, which begin to migrate to opposite ends of the cell. IV. Telophase: A full set of chromosomes reaches each pole of the cell. The mitotic spindle begins to disappear. The nucleus and nucleoli begin to reappear. Chromosomes begin to unravel into chromatin. Cytokinesis or cytoplasmic division usually occurs at the end of telophase. In plant cells cytokinesis is accomplished by the formation of a cell plate. Animal cells separate by forming a cleavage furrow.
- Telephase: Cytokinesis
Eukaryotes use two major types of cell division: mitosis and meiosis. Mitosis is used to produce new identical somatic (body) cells for replacement, growth and healing, while meiosis is used to produce sex cells (eggs and sperm).
The cell cycle is an ordered series of events involving cell growth and cell division that produces an identical pair of cells via mitosis. The length of the cell cycle is highly variable even within the cells of an individual organism. In humans, the frequency of cell turnover ranges from a few hours in early embryonic development to an average of two to five days for epithelial cells. There is also variation in the time that a cell spends in each phase of the cell cycle. When fast-dividing mammalian cells are grown in culture (outside the body under optimal growing conditions), the length of the cycle is approximately 24 hours. The timing of events in the cell cycle is controlled by mechanisms that are both internal and external to the cell.
Cells on the path to cell division proceed through a series of precisely timed and carefully regulated stages of growth, DNA replication, and division that produce two genetically identical cells. The cell cycle has two major phases: interphase and the mitotic phase (Figure 1). During interphase, the cell grows and DNA is replicated. During the mitotic phase, the replicated DNA and cytoplasmic contents are separated and the cell divides.
Figure 1: A cell moves through a series of phases in an orderly manner. During interphase, G1 involves cell growth and protein synthesis, the S phase involves DNA replication and the replication of the centrosome, and G2 involves further growth and protein synthesis. The mitotic phase follows interphase. Mitosis is nuclear division during which duplicated chromosomes are segregated and distributed into daughter nuclei. Usually the cell will divide after mitosis in a process called cytokinesis in which the cytoplasm is divided and two daughter cells are formed.
During interphase, the cell undergoes normal cellular processes while also preparing for cell division. For a cell to move from interphase to the mitotic phase, many internal and external conditions must be met. During interphase, the cell is very active biochemically. It is getting ready to divide by accumulating the required molecules and sufficient energy reserves. One very important process that happens during interphase is DNA replication. By the end of interphase, there are two identical copies of the DNA. Each chromosome is replicated and the two identical copies remain attached to each other at the centromere (Figure 2).
Figure 2: DNA replication during S phase copies each linear chromosome. The chromosomes remain attached together at a region called the centromere. Photo credit: Lisa Bartee
The centrosome is also duplicated during interphase. Each centrosome is made up of rod-like objects called centrioles. Centrioles help organize cell division. Centrioles are not present in the centrosomes of other eukaryotic species, such as plants and most fungi. Spindle fibers connect the centrosomes to the centromere of each chromosome. The spindle fibers will direct movement of the chromosomes during the rest of the process.
Figure 3(a) Structure of the centrioles making up the centrosome. (b) Centrioles give rise to the mitotic spindle (grey threadlike structures). Photo credit: CNX OpenStax Microbiology.
The Mitotic Phase
Figure 4: Mitosis in onion root cells. The cells in this image are in various stages of mitosis. (Credit: Spike Walker. Wellcome Imagesimages@wellcome.ac.uk)
To make two daughter cells, the contents of the nucleus and the cytoplasm must be divided. The mitotic phase is a multistep process during which the copied chromosomes are lined up in the center of the cell, then pulled apart to opposite ends of the cell. The cell is then divided into two new identical daughter cells. The first portion of the mitotic phase, mitosis, is composed of five phases, which accomplish nuclear division (Figure 5). The second portion of the mitotic phase, called cytokinesis, is the physical separation of the cytoplasmic components into two daughter cells. Although the stages of mitosis are similar for most eukaryotes, the process of cytokinesis is quite different for eukaryotes that have cell walls, such as plant cells.
Figure 5 Summary of the process of mitosis. Photo credit Oganesson007, Wikimedia.
To summarize the process of mitosis:
- Somatic (body) cell receives a signal that it is time to divide. This might be to achieve scheduled replacement, heal a wound or to allow the organism to grow larger.
- DNA replication takes place during interphase. The end result is two identical copies of each chromosome connected at the centromere. These identical copies are called sister chromatids.
- During mitosis (division of the nucleus), the replicated chromosomes condense (wind up tightly), then spindle fibers attach to the centromere of each chromosome. The spindle fibers pull on the chromosomes, which causes them to line up in the center of the cell.
- The centromeres separate and the spindle fibers shorten, pulling one sister chromatid to either end of the cell.
- During cytokinesis, the cytoplasm of the cell is divided into two new cells by the formation of a new cell membrane between the daughter cells.
- The result of mitosis is two identical somatic cells.
- There is a lot of transcription required to achieve a perfect replication. The mRNA carries an immense amount of information in the form of surrogate components of DNA that are required for construction of the new DNA components to result in two complete sets of DNA for the mother and daughter cells.
- If the purpose of mitosis was to replace a worn-out cell, it will initiate a process called apoptosis, cellular suicide, to remove the faulty cell from the entity. There is a lot of ‘trash’ that accumulates and must be disposed of.
- Once the patterns, the mRNA, have done their job, their usefulness is finished.
Phases of Mitosis Presented in Greater Detail
If you would like to read more about what occurs, you can find this information below.
The nuclear envelope starts to break down, and the organelles (such as the Golgi apparatus and endoplasmic reticulum), fragment and move toward the edges of the cell. The nucleolus disappears. The centrosomes begin to move to opposite poles of the cell. Microtubules that will form the mitotic spindle extend between the centrosomes, pushing them farther apart as the microtubule fibers lengthen. The sister chromatids begin to coil more tightly with the aid of condensing proteins and become visible under a light microscope.
Figure 6 Prophase. Photo credit Kelvin13; Wikimedia.
During prometaphase,the “first change phase,” many processes that were begun in prophase continue to advance. The remnants of the nuclear envelope fragment. The mitotic spindle continues to develop as more microtubules assemble and stretch across the length of the former nuclear area. Chromosomes become more condensed and discrete. Each sister chromatid develops a protein structure called a kinetochorein the centromeric region.
Figure 7 Prometaphase. Photo credit Kelvin13; Wikimedia.
The proteins of the kinetochore attract and bind mitotic spindle microtubules. As the spindle microtubules extend from the centrosomes, some of these microtubules come into contact with and firmly bind to the kinetochores. Once a mitotic fiber attaches to a chromosome, the chromosome will be oriented until the kinetochores of sister chromatids face the opposite poles. Eventually, all the sister chromatids will be attached via their kinetochores to microtubules from opposing poles. Spindle microtubules that do not engage the chromosomes are called polar microtubules. These microtubules overlap each other midway between the two poles and contribute to cell elongation. Astral microtubules are located near the poles, aid in spindle orientation, and are required for the regulation of mitosis.
Figure 8 During prometaphase, mitotic spindle microtubules from opposite poles attach to each sister chromatid at the kinetochore. In anaphase, the connection between the sister chromatids breaks down, and the microtubules pull the chromosomes toward opposite poles.
During metaphase,the “change phase,” all the chromosomes are aligned in a plane called the metaphase plate, or the equatorial plane, midway between the two poles of the cell. The sister chromatids are still tightly attached to each other by cohesin proteins. At this time, the chromosomes are maximally condensed.
Figure 9 Metaphase. Photo credit Kelvin13;
During anaphase, the “upward phase,” the cohesin proteins degrade, and the sister chromatids separate at the centromere. Each chromatid, now called a chromosome, is pulled rapidly toward the centrosome to which its microtubule is attached. The cell becomes visibly elongated (oval shaped) as the polar microtubules slide against each other at the metaphase plate where they overlap.
Figure 10 Anaphase. Photo credit Kelvin13; Wikimedia.
During telophase, the “distance phase,” the chromosomes reach the opposite poles and begin to decondense (unravel), relaxing into a chromatin configuration. The mitotic spindles are depolymerized into tubulin monomers that will be used to assemble cytoskeletal components for each daughter cell. Nuclear envelopes form around the chromosomes, and nucleosomes appear within the nuclear area.
Figure 11 Telophase. Photo credit Kelvin13; Wikimedia.
Cytokinesis, or “cell motion,” is the second main stage of the mitotic phase during which cell division is completed via the physical separation of the cytoplasmic components into two daughter cells. Division is not complete until the cell components have been divided and completely separated into the two daughter cells. Although the stages of mitosis are similar for most eukaryotes, the process of cytokinesis is quite different for eukaryotes that have cell walls, such as plant cells.
In cells such as animal cells that lack cell walls, cytokinesis follows the onset of anaphase. A contractile ring composed of actin filaments forms just inside the plasma membrane at the former metaphase plate (Figure 12). The actin filaments pull the equator of the cell inward, forming a fissure. This fissure, or “crack,” is called the cleavage furrow. The furrow deepens as the actin ring contracts, and eventually the membrane is cleaved in two.
In plant cells, a new cell wall must form between the daughter cells. During interphase, the Golgi apparatus accumulates enzymes, structural proteins, and glucose molecules prior to breaking into vesicles and dispersing throughout the dividing cell (Figure 12). During telophase, these Golgi vesicles are transported on microtubules to form a phragmoplast (a vesicular structure) at the metaphase plate. There, the vesicles fuse and coalesce from the center toward the cell walls; this structure is called a cell plate. As more vesicles fuse, the cell plate enlarges until it merges with the cell walls at the periphery of the cell. Enzymes use the glucose that has accumulated between the membrane layers to build a new cell wall. The Golgi membranes become parts of the plasma membrane on either side of the new cell wall.
Figure 12 During cytokinesis in animal cells, a ring of actin filaments forms at the metaphase plate. The ring contracts, forming a cleavage furrow, which divides the cell in two. In plant cells, Golgi vesicles coalesce at the former metaphase plate, forming a phragmoplast. A cell plate formed by the fusion of the vesicles of the phragmoplast grows from the center toward the cell walls, and the membranes of the vesicles fuse to form a plasma membrane that divides the cell in two.
Summary of Mitosis and Cytokinesis
Figure 13 Mitosis is divided into five stages—prophase, prometaphase, metaphase, anaphase, and telophase. The pictures at the bottom were taken by fluorescence microscopy of cells artificially stained by fluorescent dyes: blue fluorescence indicates DNA (chromosomes) and green fluorescence indicates microtubules (spindle apparatus).
The Cell Cycle and Mitosis
From https://openlab.citytech.cuny.edu/bio-oer/cell-division/. Edited by Rosana Zenil-Ferguson (08-23-2019)
The cell cycle refers to a series of events that describe the metabolic processes of growth and replication of cells. The bulk of the cell cycle is spent in the “living phase”, known as interphase. As you read previously, the interphase has 3 distinct phases: G1 (Gap 1), S (Synthesis) and G2 (Gap 2),
Interphase is further broken down into 3 distinct phases: G1 (Gap 1), S (Synthesis) and G2 (Gap 2). G1 is the phase of growth when the cell is accumulating resources to live and grow. After attaining a certain size and having amassed enough raw materials, a checkpoint is reached where the cell uses biochemical markers to decide if the next phase should be entered. If the cell is in an environment with enough nutrients in the environment, enough space and having reached the appropriate size, the cell will enter the S phase. S phase is when metabolism is shifted towards the replication (or synthesis) of the genetic material. During S phase, the amount of DNA in the nucleus is doubled and copied exactly in preparation to divide. The chromosomes at the end of G1 consist of a single chromatid. At the end of S phase, each chromosome consists of two identical sister chromatids joined at the centromere. When the DNA synthesis is complete, the cell continues on to the second growth phase called G2. Another checkpoint takes place at the end of G2 to ensure the fidelity of the replicated DNA and to re-establish the success of the cell’s capacity to divide in the environment. If conditions are favorable, the cell continues on to mitosis.
Mitosis is the process of nuclear division used in conjunction with cytokinesis to produce 2 identical daughter cells. Cytokinesis is the actual separation of these two cells enclosed in their own cellular membranes. Unicellular organisms utilize this process of division in order to reproduce asexually. Prokaryotic organisms lack a nucleus, therefore they undergo a different process called binary fission. Multicellular eukaryotes undergo mitosis for repairing tissue and for growth. The process of mitosis is only a short period of the lifespan of cells.
Mitosis is traditionally divided into four stages:
prophase, metaphase, anaphase, and telophase. The actual events of mitosis are not discreet but occur in a continuous sequence—separation of mitosis into four stages is merely convenient for our discussion and organization. During these stages, important cellular structures are synthesized and perform the mechanics of mitosis. For example, in animal cells, two microtubule-organizing centers called centrioles replicate. The pairs of centrioles move apart and form an axis of proteinaceous microtubules between them called spindle fibers. These spindle fibers act as motors that pull at the centromeres of chromosomes and separate the sister chromatids into newly recognized chromosomes. The spindles also push against each other to stretch the cell in preparation of forming two new nuclei and separate cells. In animal cells, a contractile ring of actin fibers cinches together around the midline of the cell to coordinate cytokinesis. This cinching of the cell membrane creates a structure called the cleavage furrow.
Eventually, the cinching of the membrane completely separates into two daughter cells. Plant cells require the production of new cell wall material between daughter cells. Instead of a cleavage furrow, the two cells are separated by a series of vesicles derived from the Golgi. These vesicles fuse together along the midline and simultaneously secrete cellulose into the space between two cells. This series of vesicles is called the cell plate.
The four stages of mitosis in figures.
4. Telophase and Cytokinessis
Cellular Garbage Disposals Clean Up
When proteins enter the proteasome, they’re chopped into bits for re-use.
Cells rely on garbage disposal systems to keep their interiors neat and tidy. If it weren’t for these systems, cells could look like microscopic junkyards — and worse, they might not function properly.
So constant cleaning is a crucial biological process, and if it goes wrong, it can cause serious problems. Scientists funded by the National Institutes of Health are therefore working to understand the cell’s janitorial services to find ways to combat these malfunctions.
One of the cell’s trash processors is called the proteasome. It breaks down proteins, the building blocks and mini-machines that make up many cell parts. The barrel-shaped proteasome disassembles damaged or unwanted proteins, breaking them into bits that the cell can re-use to make new proteins. In this way, the proteasome is just as much a recycling plant as it is a garbage disposal.
How does the cell know which proteins to keep and which to trash? The 2004 Nobel Prize in chemistry went to three scientists for answering that question. They found that the cell labels its refuse with a tiny protein tag called ubiquitin. Once a protein has the ubiquitin label, the proteasome can grab it, put it inside the barrel, break it down and release the pieces.
Proteins aren’t the only type of cellular waste. Cells also have to recycle compartments called organelles when they become old and worn out. For this task, they rely on an organelle called the lysosome, which works like a cellular stomach. Containing acid and several types of digestive enzymes, lysosomes digest unwanted organelles in a process termed autophagy, from the Greek words for “self” and “eat.” The multipurpose lysosome also processes proteins, bacteria and other “food” the cell has engulfed.
An inability to make one of the lysosomal enzymes can lead to a rare, life-threatening sickness called a lysosomal storage disease. There are more than 40 different lysosomal storage diseases, depending on the kind of trash that’s unprocessed. These diseases can affect many organs, including the brain, heart and bones.
While cells mainly use proteasomes and lysosomes, they have a couple of other options for trash disposal.
Sometimes they simply hang onto their trash, performing the cellular equivalent of sweeping it under the rug. Scientists propose that the cell may pile all the unwanted proteins together in a glob called an aggregate to keep them from gumming up normal cellular machinery.
For example, a protein called islet amyloid polypeptide builds up in aggregates in the pancreas of people with type 2 diabetes. Other proteins form aggregates in certain brain diseases. Scientists are still trying to understand what these trash piles do and whether they’re helpful or harmful.
If the garbage can’t be digested by lysosomes, the cell can sometimes spit it out in a process called exocytosis. Once outside the cell, the trash may encounter enzymes that can take it apart, or it may simply form a garbage heap called a plaque. Unfortunately, these plaques outside the cell may be harmful, too.
The cell also has ways to toss out some poisons that get inside. The mRNA are the protein coding transcripts. Their role in DNA replication is to provided enzymes involved in the synthesis of DNA components to that which are involve in replication. So, the DNA cannot replicate in the absence of mRNA. This leads to the classical dilemma of which comes first RNA or DNA. although several examples for RNA world exists like ribozymes. But yes… DNA cannot be replicated without the help of mRNA.
In animal viruses, the virus attaches to specific receptors on the plasma membrane and the whole virus is taken in by endocytosis (pinocytosis or phagocytosis). The viral envelope (if present) is stripped off inside the cell, and the separation of the viral genome f
Organisms rid the cells of waste products that could be detrimental to the cell. Organisms from the mitosis cycle, particularly, are significant and must be packaged up and ejected from the cell, as they are no longer needed or useful.
As waste particles accumulate in a cell, the waste will move out of the cell and be eliminated via an exocytotic process. The mRNA and other components of mitosis will be accumulated together and wrapped tightly in a proteinaceous vesicle, called an exosome. The exosome will be passed through the cell wall and ejected into the fluid flow. This is now a virus, which is passed along and eliminated. The coating prevents the virus from being released both while in the body and after expulsion. Countless quadrillions of viruses are produced and excreted into the environment at large, not only from humans, but from all of the eukaryotic life forms of the planet. They are tiny submicroscopic particles of waste, inert, dead, harmless. Only if a virus can be somehow re-introduced into the interior of a eukaryotic cell could there be any further involvement in human metabolism.
This brings us to the bio-weapons laboratory of US, China or Russia, where any and all forms of weapons are seen as useful and valuable. The virus is seen as a useful item to these fiends, as it is typically misunderstood, especially on the part of humans who have never received any viable education on the subject. Secondly, it is, for all practical purposes, invisible, making it an easy process of distorting its nature from an invisible particle of dirt into some kind of living predator that is trying to ‘infect’ everyone to bring death and misery to the world. This is all the sick dreaming of military and medical groups who need something to threaten humans, but which humans can not understand or even see, let alone reject.
Can you now grasp the nature of the situation humans are facing today with the alleged corona pandemic? They have the resources to present this to the world populations as the dire threat they are trying to make of it, using their owned and operated media outlets and the control over independent media via absolute censorship. If the populations allow this to evolve as they have it planned, the fear being instilled into humans will take humanity into the abyss.
If you would choose to dismiss this information because you do not see any possible reason why the hidden government would wish to do this to you, then you should read some of the numerous essays I have presented on this site, that explain the nature of their motivation.
Unless otherwise noted, images on these page are licensed under CC-BY 4.0 by OpenStax.
OpenStax, Biology. OpenStax CNX. May 27, 2016 http://cnx.org/contents/s8Hh0oOc@9.10:Vbi92lHB@9/The-Cell-Cycle