Cell Division. Many Stages of Mitosis.

Stages of Mitosis.

The Many Stages of Mitosis: Cell Division

Mitosis, also known as cell division, is the most common of the two types of cell division, and it is characterized by the separation of the cell into two smaller cells called daughter cells. There are five distinct stages of mitosis in eukaryotic organisms including prophase, metaphase, anaphase, telophase, and cytokinesis. In multicellular organisms like humans, mitosis allows for the replacement of old or damaged cells with new ones through a process known as cellular differentiation.

Cell Division Process:

Cell division is the process in which a cell divides into two daughter cells. The two processes are mitosis and meiosis. They both occur as part of the process that allows for growth and replication. However, there are many differences between them, including the way they replicate DNA and the number of chromosomes each has. Mitosis takes place when one parent cell divides to form two daughter cells, with each receiving an identical copy of the parental genome (DNA). Meiosis only happens after prophase I and II during gametogenesis. It is not until this point where all four copies of parental chromosome pairs split up to form haploid sperm or egg cells.

Cell Division

Interphase:

In this stage, cells will grow and then stop growing to prepare for mitosis. Cells that are near the end of their cell cycle will start to produce proteins needed for cell division. Proteins will also be made to repair any DNA damage from previous cycles. A protein called cyclin will be produced and activate another protein called cdk which causes the nuclear membrane to break down and cytokinesis begins. The nucleus breaks into two new nuclei and each one takes half of the chromosomes. Chromosomes pair up with a matching partner through crossing over. When all is done, cytokinesis ends by forming a cytoplasmic bridge between the two new daughter cells. The two new daughter cells now go through interphase. Once they enter interphase, both sets of chromosomes will contain identical genetic material.

Interphase

Prophase:

In prophase, the chromosomes are condensed and tightly coiled. Centrioles migrate to opposite poles of the cell. The nuclear membrane breaks down, and the nucleolus disappears from the center. The spindle fibers begin to form between the two new nuclei that will eventually divide. Nucleoli begin to reappear. Centrosomes split into two centrioles which move to opposite sides of the cell. The nuclear membrane begins reforming. Prophase I ends when all chromosome pairs have moved to their respective centromeres in preparation for mitotic division. Chromosomes uncoil and line up on either side of the equator (the metaphase plate). Chromatids become connected by strands called chiasmata during anaphase I as sister chromatids pull apart towards opposite poles. During telophase, each half of the cell grows a new nucleus while forming cytoplasmic extensions called telophores.

Prophase

Metaphase:

During the Metaphase stage, chromosomes line up along the equator. The spindle fibers attach to each chromosome and pull them apart so that each half gets a copy. Once the cell has split into two, two daughter cells are created with identical DNA but different organelles, cytoplasm, and other components. These daughter cells are called daughter cells because they come from the parent cell, or mother cell. Each new organism will have an exact copy of all its genes in every single chromosome. These cells are now called daughter because they come from their parent's mother-cell, or their mother. They will each have exactly the same set of genes in their entire genome, but the type of nuclei and mitochondria within these cells is different. One reason for this is because those cellular structures divide during mitosis too. Now that our illustration can show us what happens after metaphase and cytokinesis (the final stages) let’s take a closer look at these stages as well.

Metaphase

Anaphase:

Mitosis is the process by which one cell divides into two cells. There are four phases in mitosis, and they occur in a particular order. The first phase is the prophase, where the chromatin condenses and becomes visible under a microscope. The second phase is metaphase, where the chromosomes line up at the center of the cell. This process is known as metaphase because it's when you're halfway through division. It only lasts for about five minutes before you enter the third stage, anaphase. In anaphase, the chromatids or strands that form a chromosome separate from each other and move to opposite sides of the cell. The final stage is telophase, which is when each strand or chromatid has divided fully into two new daughter cells with their own nuclear envelope.

Anaphase

Telophase:

Mitosis is the process in which cells divide, or reproduce themselves. It consists of three phases: prophase, metaphase, and telophase. In this process, each chromosome replicates itself and separates into two identical sets by means of a centromere at the center. One set will be inherited by one daughter cell and the other set will be inherited by the other daughter cell. The chromosomes then align on either side of the equator in an orderly fashion. They also attach to spindle fibers that span the length of the cell. As mitotic spindles begin to contract and pull, each set of chromatids are pulled towards opposite poles. Once they reach their respective poles, they become known as daughter chromosomes that contain half of the DNA from the parent cell. Mitosis is completed when the chromosomes arrive at the end of their respective poles. Telophase begins with a nuclear membrane reforming around each group of daughter chromosomes. Each new nucleus then sends out its own set of cytoplasmic strands (known as microtubules) and organelles to form its cellular envelope, completing it.

Telophase

Cytokinesis:

Mitosis is the process by which a cell divides into two daughter cells. Cytokinesis is the final stage of mitosis, in which the nucleus and cytoplasm are separated to form two cells. In order for cytokinesis to occur, the nuclear envelope must have been broken down. The thin filament network that holds the chromatin together is split down its length by an enzyme called katanin. The result is that chromosomes separate into single strands, known as sister chromatids, each strand having one end connected to its original chromosome at the centromere. When these long threads pull apart from one another, they pull the entire nuclear membrane apart with them. In addition, microtubules found inside the spindle fiber push outwards on both sides of the membrane, creating a hole through which portions of the cytoplasm flow out (the cytosol). Eventually there will be just two daughter cells left inside the parent cell's membrane.

Cytokinesis

Karyokinesis:

Mitosis is a process in which cells divide into two daughter cells. Karyokinesis, the first stage, is the stage in which chromosomes are separated and replicated. Chromosomes are made up of DNA (deoxyribonucleic acid). The DNA has genetic information that is split into two sets in each cell during this stage. In the second stage, metaphase, the chromosomes line up at the equator to prepare for division. During anaphase, half of the chromosome pairs separate and begin moving towards opposite poles. During telophase, cytokinesis begins when the nuclear membrane disintegrates and new nuclei form around the chromosomes. Cytokinesis continues until one cell contains all of the original chromosomes and another contains none. These cells become known as daughter cells.