““Metabolically active cells, such as those of the liver, kidneys, muscles, and brain, have hundreds or thousands of mitochondria, making up some 40 per cent of the cytoplasm. The egg cell, or oocyte, is exceptional: it passes on around 100000 mitochondria to the next generation. In contrast, blood cells and skin cells have very few, or none at all; sperm usually have fewer than 100. All in all, there are said to be 10 million billion mitochondria in an adult human, which together constitute about 10 per cent of our body weight.””
