Biology: Meiosis | Quizlet

What are the two types of cells?

Diploid and Haploid

What are diploid cells?

Contains all the DNA to make an Organism. All somatic (somatic cells are the ones that make your body) cells are diploid and genetically identical because they are produced by mitosis.

What are haploid cells?

Cells that only have ½ of the DNA of the individual. They have only one chromosome from each pair. Only gametes are haploid → men ♂ → sperm cell (spermatozoid) ↳ women ♀ → egg cell (ovule) Each gamete is genetically unique because they are produced by meiosis.

What is meiosis?

Sexual cell division One diploid (2n) mother cell produces 4 daughter cells.

Prophase I

Chromosomes become visible; Nuclear membrane disappears; Nucleolus disappears; Centrioles appear Spindle fibers start to form; Chromosomes come together by pairs forming Tetrads; Chromosomes of the same pair are called homologous chromosomes; Homologous chromosomes exchange pieces of DNA in a process called crossing over. This produces genetic variability.

Tetrads

In Prophase I chromosomes come together by pairs forming Tetrads. Chromosomes of the same pair are called homologous chromosomes. Homologous chromosomes exchange pieces of DNA in a process called crossing over. This produces genetic variability.

Homologous chromosomes

In Prophase I chromosomes come together by pairs forming Tetrads. Chromosomes of the same pair are called homologous chromosomes. Homologous chromosomes exchange pieces of DNA in a process called crossing over. This produces genetic variability

Crossing over

In Prophase I chromosomes come together by pairs forming Tetrads. Chromosomes of the same pair are called homologous chromosomes. Homologous chromosomes exchange pieces of DNA in a process called crossing over. This produces genetic variability

Metaphase I:

Homologous chromosomes (duplicated) align in the equator of the cell by pairs. Spindle fibers from one end of the cell attaches to the centromere of one of the homologous chromosomes. Spindle fibers form the other end, attach to the other homologous chromosomes of the pair.

Anaphase I

Homologous (duplicated) chromosomes migrate to opposite poles.

Telophase I

Chromosomes (duplicated) only one chromosome from each pair arrive at opposite poles. Nuclear membrane forms around each set of chromosomes. Cell elongates preparing for cytokinesis I.

Cytokinesis I

Cell divides into two haploid (duplicated) cells that will enter Meiosis II.

Prophase II

Centrioles appear and migrate to opposite poles. Spindle fibers begin to form. Nuclear membrane disappears. Nucleolus disappears.

Metaphase II

Chromosomes (duplicated) align in a single line in the equator of the cell.

Anaphase II

Centromeres split. Sister chromatids migrate to opposite poles.

Telophase II

Nuclear membrane forms around each set of chromosomes. Nucleolus reappears. Cell elongates preparing for cytokinesis II

Cytokinesis II

Each cell resulting from Meiosis I, split. The result is formation of 4 haploid, genetically different cells called gametes.

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