DownloadCreate AI Presentation

Meiosis: The Reduction Division

An In-depth Study of Meiosis 1

Introduction to Meiosis

  • Meiosis is a nuclear division that occurs in germ cells of sexually reproducing organisms.
  • It produces reproductive cells called gametes.
  • Meiosis is a reduction division that reduces the chromosome number of a cell by half.
  • The entire process of meiosis results in the formation of four haploid daughter cells.
  • Chromosome number is restored after fertilization.

Meiosis 1: The Reduction Division

  • Meiosis 1 is the first round of cell division in meiosis.
  • It involves four stages: Prophase 1, Metaphase 1, Anaphase 1, and Telophase 1.
  • Prophase 1 is further subdivided into five stages: Leptotene, Zygotene, Pachytene, Diplotene, and Diakinesis.
  • Each stage has distinct events and processes.

Prophase 1: Leptotene and Zygotene

  • Leptotene: Chromosomes condense and become visible.
  • Zygotene: Chromosomal crossing over takes place between non-sister chromatids of homologous chromosomes.
  • Crossing over makes each individual unique and causes recombination.
  • Formation of bivalents occurs.

Prophase 1: Pachytene, Diplotene, and Diakinesis

  • Pachytene: Homologous chromosomes are fully synapsed, allowing further crossing over.
  • Diplotene: Synaptonemal complex breaks down and chromosomes start to separate.
  • Diakinesis: Chromosomes are fully condensed, nucleolus and nuclear membrane dissolve, mitotic spindle assembles.

Metaphase 1: Alignment of Homologous Chromosomes

  • Microtubules from opposite poles attach to the chromosomes at the kinetochores.
  • Bivalents align along the equatorial plate with random orientation.
  • Parental homologues can take up any site on the spindle.
  • Metaphase 1 marks the alignment of the bivalents.

Anaphase 1: Separation of Homologous Chromosomes

  • Homologous chromosomes separate and move to opposite poles.
  • Microtubules shorten, pulling the homologous chromosomes apart.
  • Sister chromatids remain attached at the centromere.
  • Anaphase 1 results in two haploid sets of chromosomes.

Telophase 1: Nuclear Reformation and Cell Division

  • Chromosomes reach the poles and nuclear envelopes reform around the daughter nuclei.
  • Nuclei reappear and a furrow appears in the cytoplasm.
  • The cell divides into two daughter cells.
  • Telophase 1 completes the first round of cell division in meiosis.

Related Presentations

Building a Python Web App for Data Dashboard

Building a Python Web App for Data Dashboard

Understanding Meiosis: The Process of Genetic Variation

The Power of Asking the Right Questions

Exploring the Global Impact of Foreign Music

Explaining.RF: Delivering Reliable Information to Citizens