Only the head of the sperm enters the egg during fertilization. The head contains the nucleus, which carries the father's genetic material (DNA).
Here's a breakdown of why:
- Sperm Structure: Sperm cells are made up of three main parts: the head, midpiece, and tail.
- Head: Contains the nucleus with the genetic information and an enzyme-filled cap called the acrosome.
- Midpiece: Contains mitochondria that provide energy for movement.
- Tail: Propels the sperm towards the egg.
- Fertilization: The sperm's journey to the egg involves several steps:
- Acrosome Reaction: The acrosome releases enzymes that break down the outer layers of the egg, allowing the sperm to penetrate.
- Fusion: The sperm's head fuses with the egg's membrane, delivering the genetic material.
- Tail Detachment: Once inside, the sperm's tail detaches, leaving only the head with its genetic material.
The fusion of the sperm's nucleus with the egg's nucleus marks the beginning of a new human life.
