* Genes are segments of DNA. They contain the instructions for building and maintaining an organism.
* Chromosomes are long, thread-like structures made up of DNA. They are found in the nucleus of most cells.
* A chromosome contains many genes. Think of a chromosome as a book, and each gene is a chapter in that book.
So, a gene is not a "subunit" of a chromosome in the sense that it's a smaller, independent piece. It's more accurate to say that genes are sections within the larger structure of a chromosome.
