Stages in Meiosis Flashcards

Study Notes

Meiosis Overview

Meiosis is a type of cell division that produces reproductive cells in sexually reproducing organisms.
It consists of two main stages: meiosis I and meiosis II, resulting in cells with half the chromosome number of the original.

Stages of Meiosis

The entire process includes several stages: Interphase, Prophase (I and II), Metaphase (I and II), Anaphase (I and II), Telophase (I and II), and Cytokinesis.
Interphase occurs before division when the nucleus is not actively dividing.

Meiosis I

Meiosis I is the first phase that reduces chromosome number from diploid to haploid.
In Prophase I, homologous chromosomes pair up and crossing over occurs, the spindle apparatus forms, and the nuclear envelope disintegrates.
During Metaphase I, homologous pairs line up along the equator of the cell, and spindle fibers attach to their centromeres.
Anaphase I separates homologous chromosomes which are pulled to opposite poles of the cell.
Telophase I results in haploid cells that still contain replicated chromosomes.

Meiosis II

Meiosis II closely resembles mitosis and occurs after meiosis I, involving the separation of sister chromatids.
Prophase II involves the breakdown of the nuclear envelope and the formation of spindle fibers without further chromosome replication.
In Metaphase II, sister chromatids line up at the equator, similar to metaphase in mitosis.
Anaphase II separates sister chromatids, pulling them toward opposite poles of the cell.
Telophase II leads to the formation of four haploid cells with distinct chromosomes, each encased in a nuclear envelope.

Description

Explore the essential stages of meiosis with this informative flashcard set. Each card presents key terms and definitions related to the process of meiotic cell division, essential for understanding sexual reproduction in organisms. Perfect for students studying genetics.