Inside the nucleus of a cell, there are thread-like structures called chromosomes. Each chromosome is made out of a long, coiled up strand of DNA (genetic material), which means that each chromosome contains many genes.
Normally, there are 46 chromosomes inside the nucleus of each human body cell. Chromosomes are usually found in pairs.
A diploid cell contains two complete sets of chromosomes in its nucleus, one from each parent. In humans, all body cells are diploid cells. Human diploid cells have 23 pairs of chromosomes (46 in total). The diploid number is often represented as 2n, with n being the number of chromosomes. In humans, 2n = 46.
The word haploid means half. It describes a cell that contains a single set of chromosomes. The symbol n is often used to show the haploid number. In humans, n = 23. Human sex cells (egg and sperm cells) contain a single set of chromosomes, so they are haploid cells.