Which of These Best Describes the Primary Goal of Meiosis

Which of These Best Describes the Primary Goal of Meiosis.

What is meiosis?

  • During meiosis
    1
    cell divides
    twice
    to form
    four
    daughter cells.
  • These four daughter cells only have one-half the number of chromosomes of the parent jail cell – they are haploid.
  • Meiosis produces our sex activity cells or gametes (eggs in females and sperm in males).

Meiosis can be divided into nine stages. These are divided between the start time the cell divides (meiosis I) and the second fourth dimension it divides (meiosis II):

Meiosis I

1. Interphase:

  • The DNA in the cell is copied resulting in ii identical full sets of chromosomes.
  • Outside of the nucleus are 2 centrosomes, each containing a pair of centrioles, these structures are critical for the process of cell division.
  • During interphase, microtubules extend from these centrosomes.

2. Prophase I:

  • The copied chromosomes condense into Ten-shaped structures that tin be easily seen under a microscope.
  • Each chromosome is composed of two sister chromatids containing identical genetic data.
  • The chromosomes pair up and then that both copies of chromosome ane are together, both copies of chromosome 2 are together, and so on.
  • The pairs of chromosomes may and then exchange bits of Dna in a procedure called recombination or crossing over.
  • At the end of Prophase I the membrane around the nucleus in the jail cell dissolves away, releasing the chromosomes.
  • The meiotic spindle, consisting of microtubules and other proteins, extends across the cell betwixt the centrioles.

iii. Metaphase I:

  • The chromosome pairs line up next to each other forth the centre (equator) of the cell.
  • The centrioles are at present at opposites poles of the cell with the meiotic spindles extending from them.
  • The meiotic spindle fibres attach to one chromosome of each pair.

four. Anaphase I:

  • The pair of chromosomes are then pulled autonomously past the meiotic spindle, which pulls i chromosome to one pole of the cell and the other chromosome to the opposite pole.
  • In meiosis I the sister chromatids stay together. This is different to what happens in mitosis and meiosis Two.

v. Telophase I and cytokinesis:

  • The chromosomes complete their movement to the contrary poles of the cell.
  • At each pole of the cell a total set of chromosomes get together together.
  • A membrane forms around each ready of chromosomes to create two new nuclei.
  • The single cell and then pinches in the middle to form two dissever daughter cells each containing a full set of chromosomes within a nucleus. This procedure is known as cytokinesis.

Meiosis II

6. Prophase Two:

  • Now there are 2 daughter cells, each with 23 chromosomes (23 pairs of chromatids).
  • In each of the two daughter cells the chromosomes condense over again into visible X-shaped structures that can be easily seen under a microscope.
  • The membrane effectually the nucleus in each girl jail cell dissolves away releasing the chromosomes.
  • The centrioles duplicate.
  • The meiotic spindle forms again.

seven. Metaphase Two:

  • In each of the two girl cells the chromosomes (pair of sister chromatids) line up cease-to-finish along the equator of the jail cell.
  • The centrioles are at present at opposites poles in each of the daughter cells.
  • Meiotic spindle fibres at each pole of the cell adhere to each of the sister chromatids.

8. Anaphase II:

  • The sister chromatids are then pulled to opposite poles due to the action of the meiotic spindle.
  • The separated chromatids are now individual chromosomes.

nine. Telophase II and cytokinesis:

  • The chromosomes complete their move to the opposite poles of the cell.
  • At each pole of the cell a full set of chromosomes gather together.
  • A membrane forms effectually each set of chromosomes to create two new cell nuclei.
  • This is the last phase of meiosis, however jail cell division is not complete without another circular of cytokinesis.
  • Once cytokinesis is complete there are 4 granddaughter cells, each with half a ready of chromosomes (haploid):
    • in males, these four cells are all sperm cells
    • in females, one of the cells is an egg cell while the other 3 are polar bodies (modest cells that do not develop into eggs).

Illustration showing the nine stages of meiosis.

Illustration showing the ix stages of meiosis.
Image credit: Genome Research Limited

This page was last updated on 2021-07-21

Which of These Best Describes the Primary Goal of Meiosis

Source: https://www.yourgenome.org/facts/what-is-meiosis/