Sperm

Sperm may be tiny cells, but they are 50% responsible for reproduction.

The testicles are the male reproductive organs responsible for making sperm. Males produce millions of these cells each day, yet it takes only one to fertilize an egg and create a life. Sperm is the male reproductive cell or gamete. The term “gamete” implies that the cell is half of a whole. When a sperm combines with a female gamete, or egg, it results in a human embryo.

The sperm head contains chromatin, which is the DNA material that makes up chromosomes. The midsection of the sperm contains energy-producing mitochondria. These specialized structures provide the energy necessary for the sperm cell to move. The purpose of the sperm tail, or flagellum, is to allow movement. The tail propels the sperm forward, towards an egg for fertilization.

Source: https://www.medicalnewstoday.com/articles/sperm#production

Video: https://www.youtube.com/watch?v=icTWNDK825Y