False-colour scanning electron micrograph (SEM) of a group of human chromosomes, thread-like structures in the cell nucleus that carry the genetic information in the form of genes. The chromosomes have been tilted to an angle of 30 degrees inside the specimen chamber to display their cylindridal shape. Each chromosome can be seen to consist of two strands (chromatids) joined at a region known as the centromere or kinetochore. The nucleus of every human cell contains 46 chromosomes, 23 of maternal & 23 of paternal origin. Each chromosome may construct an exact copy of itself whilst the cell is in its resting stage between successive cell divisions.