A sperm's function is to transport the male's DNA to the female's egg.
Therefore, it has to be adapted to make sure it gets there.
Sperm are small and have long tails. This is so that they can swim effectively and reach the egg.
Sperm also have lots of mitochondria so that they have enough energy to swim the distance required.
Sperm have an acrosome at the tip of their head, which releases enzymes so that it can digest its way through the egg's membrane.
Sperm have the nucleus in their head.
The head is actually pointed to increase its slip stream and allow it to travel faster.