Humans normally have 46 chromosomes in each cell, divided into 23 pairs. Two copies of chromosome 11, one copy inherited from each parent, form one of the pairs. Chromosome 11 spans about 134 million DNA building blocks (base pairs) and represents between 4 percent and 4.5 percent of the total DNA in cells.

Identifying genes on each chromosome is an active area of genetic research. Because researchers use different approaches to predict the number of genes on each chromosome, the estimated number of genes varies. Chromosome 11 likely contains about 1,500 genes. More than 150 of these genes provide instructions for making olfactory receptors, which are proteins that are used to detect different smells.

Genes on chromosome 11 are among the estimated 20,000 to 25,000 total genes in the human genome.