How Does GCSE Biology - Meiosis (2026/27 exams) Work?

Meiosis is how your body makes special cells for having babies by folding and swapping bits of your DNA like a puzzle.

Imagine you have a giant cookbook that tells you who you are. Most cells in your body, like the skin on your hand, have two full sets of these cookbooks: one from Mom and one from Dad. They call this diploid because "di" means two. But when your body needs to make a baby, it creates special cells called gametes, like sperm or egg cells. These gametes only get one set of cookbooks so that when they join up during pregnancy, the new baby gets exactly two sets again. This process is called meiosis.

First, your body copies all the pages in the cookbook so there are duplicates. Then, it does a fun swap. It takes a page from Mom’s book and swaps it with the matching page from Dad’s book. This creates new combinations of recipes, which is why you might have your dad’s nose but your mom’s eyes.

After swapping, the cell divides in two. Each new cell gets one copy of each chromosome pair. Then, those cells divide again! Now, instead of having pairs, every single piece floats alone. These final cells are haploid, meaning they hold just half the usual amount of information. It is like packing only one shoe instead of a pair into your bag.

When a sperm (haploid) meets an egg (haploid), their halves stick together to form a complete, unique cookbook set for the new baby. This special mixing ensures that no two people are exactly alike, even if they look similar!