What are three main parts of a male gamete? Out of these three parts which part fuses with the female gamete to form the zygote?

A human sperm cell consists of three distinct structural parts: the head, middle piece (midpiece), and tail (flagellum). The head contains the nucleus with tightly packed genetic material (23 chromosomes) and is capped by an acrosome, a special enzyme-containing structure that helps penetrate the egg's protective layers. The middle piece is packed with mitochondria that generate ATP (energy) to power the sperm's movement. The tail is a long, whip-like flagellum that propels the sperm forward through the female reproductive tract toward the egg.

During fertilization, only the head of the sperm fuses with the female gamete (egg) to form the zygote. When a sperm successfully penetrates an egg, the acrosome releases enzymes that break down the egg's outer coating, allowing the sperm head to enter. Once inside, the sperm's nucleus containing the male genetic material merges with the egg's nucleus containing the female genetic material, creating a zygote with a complete set of 46 chromosomes. The midpiece and tail typically remain outside the egg or degenerate after fusion, having served their purpose of transporting the genetic payload to its destination. This fusion of genetic material from both parents initiates the development of a new individual with unique genetic characteristics.