What is meiosis I and meiosis II?
Explanation: Meiosis is a way sex cells (gametes) divide. In meiosis I, homologous chromosomes separate, while in meiosis II, sister chromatids separate. Meiosis II produces 4 haploid daughter cells, whereas meiosis I produces 2 diploid daughter cells. Genetic recombination (crossing over) only occurs in meiosis I.
What happens during meiosis Part I?
In meiosis I, chromosomes in a diploid cell resegregate, producing four haploid daughter cells. It is this step in meiosis that generates genetic diversity. DNA replication precedes the start of meiosis I. During prophase I, homologous chromosomes pair and form synapses, a step unique to meiosis.
What happens in telophase I?
Telophase I is that phase when the chromosomes have finished moving to opposite ends of the cell. This will then be followed by cytokinesis producing two daughter cells. After cytokinesis, the two daughter cells would have genetically different chromosomes after meiosis I.
What happens in Prometaphase 1 of meiosis?
During prometaphase I, microtubules attach at the chromosomes’ kinetochores and the nuclear envelope breaks down. In metaphase I, the tetrads line themselves up at the metaphase plate and homologous pairs orient themselves randomly. In anaphase I, centromeres break down and homologous chromosomes separate.
Do chromosomes Decondense in telophase 1?
Chromosome decondensation (also known as relaxation or decompaction) into expanded chromatin is necessary for the cell’s resumption of interphase processes, and occurs in parallel to nuclear envelope assembly during telophase in many eukaryotes.
What is synapse in meiosis?
Meiotic synapsis is the stable physical pairing of homologous chromosomes that begins in leptonema of prophase I and lasts until anaphase of prophase I. Telomeres then cluster at a region of the inner nuclear membrane and axial elements extend and fuse along the length of the chromosomes.
In which stage does Terminalisation of Chiasmata occur?
The displacement of Chiasmata is termed as terminalization. Terminalization is completed in Diakinesis stage of prophase I of meiosis I.
What happens in Prometaphase 2 of meiosis?
During prometaphase II, the nuclear envelopes are completely broken down, and each sister chromatid forms an individual kinetochore that attaches to microtubules from opposite poles. During metaphase II, sister chromatids are condensed and aligned at the equator of the cell.
What occurs during metaphase 1 of meiosis?
In metaphase I, the homologous pairs of chromosomes align on either side of the equatorial plate. Then, in anaphase I, the spindle fibers contract and pull the homologous pairs, each with two chromatids, away from each other and toward each pole of the cell.