Sperm cells are likely to have a higher concentration of mitochondria than white blood cells, red blood cells or even the egg cells because sperm require a significant amount of energy for motility, while white blood cells have a more diverse range of energy needs. 

Sperm cells, specifically in their midpiece, contain a high concentration of mitochondria, which are the "powerhouses" of the cell, producing the energy (ATP) needed for the sperm to swim and travel towards the egg. 

Mitochondria, often called the "powerhouses of the cell," are organelles that generate energy in the form of ATP (adenosine triphosphate) through cellular respiration, a process that breaks down glucose and other molecules to produce energy.