Meiosis

Overview

In this module, we will review the process of meiosis, which is the type of cell division responsible for producing the gametes that participate in fertilization to generate new individuals. Our main focus in this module will be on the behavior of chromosomes during meiosis, but we will also consider other aspects of gametogenesis.

Objectives

1. Know the stages of meiosis, including the substages of prophase. Understand what state the chromosomes are in at each of these stages.
2. Understand that meiosis reduces the number of chromosomes in a cell by half.
3. Understand that meiosis produces random combinations of chromosomes, with each combination equally likely.
4. Understand the basic differences between meiosis and mitosis.
5. Know the basic differences between the two types of gametogenesis in animals, spermatogenesis and oogenesis.

Introduction

Meiosis is the process by which cells divide to produce gametes, which are the reproductive cells (pollen and ovum in plants, sperm and egg in animals). The main purpose of meiosis is to reduce the number of chromosomes in the cells by half. As you learned in the cell biology review, the cells of most eukaryotes are diploid; that is, they have two of each type of chromosome. Meiosis produces cells that are haploid; they have only one of each type of chromosome.