Q:

What is the difference between meiosis 1 and meiosis 2?

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Quick Answer

The essential difference between meiosis I and meiosis II is in purpose. Meiosis I is dedicated to forming two haploid cells from one diploid cell, while meiosis II is meant to split the sister chromatids in the haploid cells produced in meiosis I, creating four daughter cells. Meiosis I also recombines, or shuffles, genes on each pair of chromosomes. Meiosis I and meiosis II happen in succession.

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Full Answer

The vast majority of cells in an organism's body are diploid; they contain two pairs of every chromosome. Chromosomes are the physical structures on which genes are located. However, for the purposes of sexual reproduction, haploid cells, which contain just one copy of each chromosome, are necessary. Otherwise, the offspring produced would have too many chromosomes and could never survive.

Meiosis I shuffles the genes on the parent chromosomes to help ensure genetic diversity, and then it separates each pair of chromosomes into two new daughter cells. Each of these chromosomes are composed of two chromatids, which, because of recombination, carry different combinations of the parent's genes. The purpose of meiosis II is to split each chromatid, producing four haploid cells. These four cells are called gametes.

As an example, humans carry 46 chromosomes in their nonreproductive cells. Meiosis I in humans produces two haploid cells with 23 chromosomes, or pairs of chromatids, and meiosis II splits those cells into four new cells, each carrying 23 chromatids. These gametes are better known as sperm cells and eggs cells in humans. When they fuse during sexual reproduction, they form a cell, called a zygote, which is diploid with 46 chromosomes once again. The shuffling of genes that occurs during meiosis and the mixing of parental genes during sexual reproduction help to ensure genetic diversity in a species.

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Related Questions

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    What happens during meiosis?

    A:

    During meiosis, a cell divides into four daughter cells called gametes that are used during sexual reproduction. A cell grows larger during interphase, then goes through multiple other steps, such as prophase and metaphase, before finally dividing into four gametes.

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  • Q:

    What is the purpose of meiosis?

    A:

    Meiosis is the process of cell division that creates offspring in sexually reproducing organisms, explains a University of Illinois at Chicago website. Unlike during mitosis, meiotic cell division starts with double the number of chromosomes in diploid parent cells. Meiosis cuts this number in half forming two haploid daughter cells. When these daughter cells combine and undergo fertilization, a zygote is created and the cell begins to develop.

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    How do I describe meiosis?

    A:

    Meiosis is the process in which cells divide to produce sex cells. Meiosis takes a single cell and divides it into four different cells with half of the necessary chromosomes for human development. Meiosis creates both egg and sperm cells.

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  • Q:

    What are mitosis and meiosis?

    A:

    Mitosis and meiosis are biological functions that create cell division and enable reproduction. These two processes are similar in that they produce offspring cells, but differ in the type of cells they produce. While mitosis results in the generation of two identical daughter cells that originate from single parent cells, meiosis involves the fission of two nuclei, which produces four gametes.

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