What structure contains DNA in the form of chromosomes?

The structure that contains DNA in the form of chromosomes is the nucleus. The nucleus serves as the control center of the cell, housing the cell's genetic material organized in chromosomes, which are composed of DNA and proteins. Within the nucleus, DNA is tightly packed and protected, allowing for processes such as DNA replication and transcription to occur efficiently. This organization is crucial for maintaining the integrity of genetic information and regulating gene expression, which are essential for proper cell function and reproduction.

Mitochondria do contain DNA, but it is in a circular form and not organized into chromosomes like that in the nucleus. Ribosomes are responsible for protein synthesis and do not contain any genetic material. The endoplasmic reticulum is involved in protein and lipid synthesis but also lacks DNA. Thus, the nucleus is uniquely responsible for storing and managing the cell's genetic information in the form of chromosomes.