1. DNA (Deoxyribonucleic acid): This is the genetic material that carries the instructions for building and maintaining an organism. DNA is a long, complex molecule that is organized into genes, which are segments of DNA that code for specific proteins.

2. Proteins: These are essential for the structure and function of chromosomes. Some key protein types involved include:

* Histones: These are small, basic proteins that act as spools around which DNA wraps. This packaging helps to compact the DNA and make it more manageable within the nucleus.

* Non-histone proteins: These are a diverse group of proteins involved in various functions related to chromosomes, such as replication, repair, and gene expression.

How they are organized:

* DNA wraps around histones to form structures called nucleosomes.

* Nucleosomes are then further compacted into a more complex structure called chromatin, which is the "stringy" form of DNA found in the nucleus when the cell is not dividing.

* During cell division, the chromatin condenses even further into the familiar X-shaped structures we call chromosomes.

In summary: Chromosomes are made up of DNA, which carries the genetic information, and proteins that provide structural support and help regulate DNA function.