Chromosomes are thread-like structures located inside the nucleus of animal and plant cells. Each chromosome is made up of protein and a single molecule of deoxyribonucleic acid (DNA).
The unique structure of chromosomes keeps DNA tightly wrapped around spool- like proteins, called histones. Without this kind of packaging, DNA molecules would be too long to fit inside the cells.
DNA molecules in a single human cell if unwound from their histones and placed end to end, they would measure 6 feet in length.
Chromosomes play a key part in ensuring that DNA is accurately copied and distributed to new daughter cells as the parent cell divides to form new cells.
