Every cell contains all of the DNA for an organism -- for humans, this means all 46 chromosomes are found in every cell in the body except for sex cells.

DNA and Cells

Each chromosome contains many genes. Each gene codes for a protein that expresses a trait. Different cells perform different jobs and have different genes that are expressed.

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​Genes

Gene Expression

Each pair of chromosomes contains one chromosome from the father and one chromosome from the mother.

Some genes are expressed and some are not. Gene expression can also be affected by the environment.