Méiose et ses Phases

<p>Maintenir constant le nombre de chromosomes (A)</p> Signup and view all the answers

<p>Ovaires (C)</p> Signup and view all the answers

<p>Spermatocyte I (B)</p> Signup and view all the answers

<p>Recombinaisons génétiques (B)</p> Signup and view all the answers

<p>Métaphase 1 (C)</p> Signup and view all the answers

<p>Elle réduit le nombre de chromosomes de moitié. (B)</p> Signup and view all the answers

<p>Cellules haploïdes. (C)</p> Signup and view all the answers

<p>Formation d'un zygote diploïde. (A)</p> Signup and view all the answers

<p>Au cours de la phase S. (A)</p> Signup and view all the answers

<p>Elle produit des cellules diploïdes. (D)</p> Signup and view all the answers

<p>Des cellules haploïdes. (A)</p> Signup and view all the answers

<p>La méiose produit quatre cellules, la mitose en produit deux. (D)</p> Signup and view all the answers

<p>Dupliquer au cours de la phase S. (C)</p> Signup and view all the answers

<p>Un brassage d'allèles au sein d'une même paire de chromosomes (D)</p> Signup and view all the answers

<p>Ils sont des points de connexion durant le crossing-over (C)</p> Signup and view all the answers

<p>Ils échangent des segments entre chromatides non sœurs (A)</p> Signup and view all the answers

<p>À partir du centromère (D)</p> Signup and view all the answers

<p>Une condensation accrue des chromosomes a lieu (D)</p> Signup and view all the answers

<p>La longueur des chromosomes (D)</p> Signup and view all the answers

<p>Les homologues s'attachent en certains points (C)</p> Signup and view all the answers

<p>Les chromatides restent liées par des chiasmas (B)</p> Signup and view all the answers

<p>L'enveloppe nucléaire se fragmente. (B)</p> Signup and view all the answers

<p>5 (B)</p> Signup and view all the answers

<p>Ils unissent les chromatides homologues. (C)</p> Signup and view all the answers

<p>Métaphase I (C)</p> Signup and view all the answers

<p>23 tétrades sont présentes. (C)</p> Signup and view all the answers

<p>Diacinèse (B)</p> Signup and view all the answers

<p>Ils sont au stade de diacinèse. (A)</p> Signup and view all the answers

<p>Crossing over (B)</p> Signup and view all the answers

<p>La production de cellules haploïdes (D)</p> Signup and view all the answers

<p>Les chromosomes homologues (B)</p> Signup and view all the answers

<p>Les centromères ne se divisent pas lors de la méiose I (D)</p> Signup and view all the answers

<p>Maintenir les paires de chromosomes homologues ensemble (D)</p> Signup and view all the answers

<p>Chaque chromosome est formé de deux chromatides sœurs (B)</p> Signup and view all the answers

<p>Les cytoplasmes des cellules filles se divisent (B)</p> Signup and view all the answers

<p>Comme une division équationnelle (B)</p> Signup and view all the answers

<p>Anaphase I (B)</p> Signup and view all the answers

A specialized cell division that produces haploid gametes from diploid cells, ensuring genetic diversity in sexually reproducing organisms.

The first division in meiosis where homologous chromosomes pair up, exchange genetic information, and separate, resulting in two haploid cells.

The second division in meiosis where sister chromatids separate, resulting in four haploid cells.

The process of DNA replication that occurs before meiosis starts, doubling the amount of genetic material.

The longest phase of meiosis I, divided into five stages, where chromosomes condense, pair up, exchange genetic material, and prepare for separation.

The first stage of prophase I where chromosomes become visible and begin to condense.

The stage of prophase I where homologous chromosomes pair up, forming a structure called a bivalent, through a process called synapsis.

The stage of prophase I where chromosomes are fully paired, and the exchange of genetic material between homologous chromosomes, called crossing over, occurs.

The stage of prophase I where the synaptonemal complex starts to break down, and homologous chromosomes remain linked by chiasmata.

The final stage of prophase I where chromosomes condense further and detach from the nuclear envelope.

The stage of meiosis I where bivalents line up at the center of the cell, and the chromosome number is halved.

The stage of meiosis I where homologous chromosomes separate and move towards opposite poles of the cell, but centromeres do not split.

The stage of meiosis I where chromosomes reach opposite poles, and the cytoplasm divides, resulting in two haploid daughter cells.

This division is similar to mitosis, where each daughter cell from meiosis I goes through a second division, ultimately resulting in four haploid daughter cells.

The stage of meiosis II where chromosomes condense again.

The stage of meiosis II where chromosomes line up at the center of the cell.

The stage of meiosis II wherein centromeres split, and sister chromatids separate, migrating to opposite poles.

The stage of meiosis II where chromosomes reach the opposite poles, and the cytoplasm divides, resulting in four haploid daughter cells, which are gametes.

The generation of genetically unique daughter cells during meiosis, achieved through two key mechanisms.

The random separation of homologous chromosomes into daughter cells during metaphase I, leading to unique combinations of maternal and paternal chromosomes.

The exchange of genetic material between homologous chromosomes during prophase I, creating new combinations of alleles.

Meiosis is essential for sexual reproduction, producing haploid gametes, which fuse to form a diploid zygote, initiating the development of a new organism.

Meiosis ensures genetic diversity within a species, by creating unique combinations of genes in each generation.

Each parent contributes one set of chromosomes to their offspring. Meiosis ensures that the chromosome number is maintained from generation to generation.

Meiosis takes place in the reproductive organs - testes in males and ovaries in females.

Specific cells undergo meiosis in reproductive organs. In males, these are spermatocytes I, and in females, they are oocytes I.