How many daughter cells are produced at the end of mitosis

During interphase, microtubules extend from these centrosomes. Prophase: The chromosomes condense into X-shaped structures that can be easily seen under a microscope. Each chromosome is composed of two sister chromatids, containing identical genetic information. The chromosomes pair up so that both copies of chromosome 1 are together, both copies of chromosome 2 are together, and so on.

At the end of prophase the membrane around the nucleus in the cell dissolves away releasing the chromosomes. The mitotic spindle, consisting of the microtubules and other proteins, extends across the cell between the centrioles as they move to opposite poles of the cell. Metaphase: The chromosomes line up neatly end-to-end along the centre equator of the cell. The centrioles are now at opposite poles of the cell with the mitotic spindle fibres extending from them.

The mitotic spindle fibres attach to each of the sister chromatids. Anaphase: The sister chromatids are then pulled apart by the mitotic spindle which pulls one chromatid to one pole and the other chromatid to the opposite pole. Telophase: At each pole of the cell a full set of chromosomes gather together.

A membrane forms around each set of chromosomes to create two new nuclei. The single cell then pinches in the middle to form two separate daughter cells each containing a full set of chromosomes within a nucleus. This process is known as cytokinesis. By the end of meiosis, the resulting reproductive cells, or gametes , each have 23 genetically unique chromosomes. The overall process of meiosis produces four daughter cells from one single parent cell. Each daughter cell is haploid, because it has half the number of chromosomes as the original parent cell.

Andrew Hoyt, a biologist and professor at Johns Hopkins University. Unlike in mitosis, the daughter cells produced during meiosis are genetically diverse. Homologous chromosomes exchange bits of DNA to create genetically unique, hybrid chromosomes destined for each daughter cell.

Before meiosis begins, some important changes take place within the parent cells. First, each chromosome creates a copy of itself. These duplicated chromosomes are known as sister chromatids. They are fused together and the point where they are joined is known as the centromere. Fused sister chromatids roughly resemble the shape of the letter "X. Meiosis occurs over the course of two rounds of nuclear divisions, called meiosis I and meiosis II, according to Nature Education's Scitable.

Furthermore, meiosis I and II are each divided into four major stages: prophase, metaphase, anaphase and telophase. Meiosis I is responsible for creating genetically unique chromosomes. Sister chromatids pair up with their homologs and exchange genetic material with one another. At the end of this division, one parent cell produces two daughter cells, each carrying one set of sister chromatids.

Meiosis II closely resembles mitosis. The two daughter cells move into this phase without any further chromosome duplication. The sister chromatids are pulled apart during this division. A total of four haploid daughter cells are produced during the course of meiosis II.

Having no X chromosome results in early embryonic death. The two copies of a particular chromosome, such as chromosome 1, are called homologous. The karyotype image above shows the homologous pairs for all the autosomes. Homologous chromosomes are not identical to each other, unlike sister chromatids. They frequently have different variants of the same hereditary information — such as blue eye color vs brown eye color, or blood type A versus blood type B.

Mitosis Mitosis produces two daughter cells that are genetically identical to each other, and to the parental cell. Each chromosome now consists of a joined pair of identical sister chromatids. During mitosis the sister chromatids separate and go to opposite ends of the dividing cell.

All eukaryotic cells replicate via mitosis, except germline cells that undergo meiosis see below to produce gametes eggs and sperm. This animation below shows the packaging of DNA and condensation of chromosomes as a cell undergoes mitosis. This is a special sequence of 2 cell divisions that produces haploid gametes from diploid germline cells. NOVA has a good interactive side-by-side comparison of mitosis and meiosis on this page: How cells divide Meiosis sets the stage for Mendelian genetics.

Students need to know that most of the genetics action occurs in the first meiotic division:. The last point appears to be the most difficult for students to grasp.

Consider the X and Y chromosomes. They pair in prophase I, and then separate in the first division. Each cell now has only one sex chromosome, like a haploid cell. One way of thinking about ploidy is the number of possible alleles for each gene a cell can have. Right after meiosis I, the homologous chromosomes have separated into different cells. Each homolog carries one copy of the gene, and each gene could be a different allele, but these two homologs are now in two different cells.

Watch this video for a summary of meiosis. Key Questions How did sexual reproduction evolve? What happens when meiosis goes wrong? Key Concepts chromosome meiosis haploid diploid recombination. Topic rooms within Genetics Close. No topic rooms are there. Browse Visually. Other Topic Rooms Genetics. Student Voices. Creature Cast. Simply Science. Green Screen. Green Science. Bio 2. The Success Code.

Why Science Matters. The Beyond. Plant ChemCast. Postcards from the Universe. Brain Metrics. Mind Read. Eyes on Environment. Accumulating Glitches.

Saltwater Science. Microbe Matters. You have authorized LearnCasting of your reading list in Scitable. Do you want to LearnCast this session? This article has been posted to your Facebook page via Scitable LearnCast. Change LearnCast Settings. Scitable Chat.

Register Sign In.