Chromosomes are thread-like structures located in the nucleus of cells, made up of DNA and proteins. They carry genetic information that determines an organism's traits and functions. Humans typically have 46 chromosomes, arranged in 23 pairs, with one set inherited from each parent. Each chromosome contains many genes, which are segments of DNA that code for specific proteins. During cell division, chromosomes become tightly packed to ensure accurate distribution to daughter cells. This process is crucial for growth, development, and reproduction. Abnormalities in chromosome number or structure can lead to genetic disorders, such as Down syndrome or Turner syndrome.