1. DNA (Deoxyribonucleic acid): This is the genetic material that carries the instructions for building and maintaining an organism. It's arranged in a long, linear molecule that's tightly coiled and packaged.

2. Proteins: These play a crucial role in the structure and function of chromosomes. They act as a scaffold to organize and support the DNA, ensuring it's properly packaged and can be accessed when needed. The major protein components of chromosomes are:

* Histones: These are small, basic proteins that bind to DNA, forming a bead-like structure called nucleosomes. They help compact the DNA and regulate gene expression.

* Non-histone proteins: These are a diverse group of proteins that perform various functions in chromosome structure and activity. Some examples include:

* Topoisomerases: These enzymes help untangle and prevent DNA from becoming overly twisted during replication and transcription.

* Chromatin remodeling complexes: These complexes modify the structure of chromatin, allowing access to DNA for processes like transcription.

* Cohesins and condensins: These proteins play crucial roles in holding sister chromatids together during cell division and in the condensation of chromosomes.

Therefore, chromosomes are complex structures made up of DNA and a variety of proteins that work together to ensure the proper organization, replication, and expression of our genetic information.