What is a chromosome?

A chromosome is a long piece of DNA that is found in the nucleus of a cell.

Each chromosome is made of several genes and each gene is made up of DNA.

Think of DNA as a small building block, like a brick.

Then multiple bricks come together to build a wall (gene).

Then multiple walls built on top of each other form a whole skyscraper (chromosome).

(Finally, many skyscrapers side by side form a whole city (all chromosomes in the nucleus)).

Hope this helps :)

Structures of DNA that code for the characteristics of an organism. Humans have 23 pairs of chromosomes, each of which contains many genes.