Are chromosomes made up of RNA?

It's made up of DNA. The two major types of RNA are: mRNA, and tRNA, or messenger and transfer RNA. mRNA is created inside the nucleus after the chromosomes unwind into the long strands of DNA. tRNA helps to create proteins (basically like the machines of a cell) by bringing individual amino acids to the ribosome which has attached to the mRNA and reads the 3-base codons that code for each amino acid. These form a big long chain of amino acids that fold into secondary, tertiary, and even quaternary forms and make proteins. There is also rRNA, or ribosomal RNA which folds up to make ribosomes. Ribosomal RNA and Transfer RNA are known as Non-Coding RNA or ncRNA because they don't code for proteins and instead just fold up and do their work on their own without having to make proteins.