This narrated animation allows the learner to understand how six feet of DNA can be tightly packed to fit inside the nucleus of every human cell. [1:43]

Biology 2e is designed to cover the scope and sequence requirements of a typical two-semester biology course for science majors. The text provides comprehensive coverage of foundational research and core biology concepts through an evolutionary lens. Biology includes rich features that engage students in scientific inquiry, highlight careers in the biological sciences, and offer everyday applications. The book also includes various types of practice and homework questions that help students understand—and apply—key concepts. The 2nd edition has been revised to incorporate clearer, more current, and more dynamic explanations, while maintaining the same organization as the first edition. Art and illustrations have been substantially improved, and the textbook features additional assessments and related resources.

By the end of this section, you will be able to do the following:

Describe the structure of prokaryotic and eukaryotic genomes
Distinguish between chromosomes, genes, and traits
Describe the mechanisms of chromosome compaction

The scientists and experiments that discovered that DNA is coiled into chromosomes are the topic of this article. Article includes animations, pictures, video, biographical information, and quiz questions that are accessed by clicking on buttons along the bottom of the page.