This document discusses chromosomes and their structure and function. It begins with the historical discovery of chromosomes in 1875 and defines them as stainable nuclear components that duplicate and are passed from parents to offspring. It describes the main types of chromosomes, including autosomes and sex chromosomes. It details the structure of chromosomes and their compaction into nucleosomes and higher order packaging. Key parts like the centromere and kinetochores are explained. The functions of chromosomes in heredity, growth, and determining sex are summarized. Special giant chromosome types like polytene and lampbrush chromosomes found in insect salivary glands and amphibian oocytes respectively are also outlined.