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:

List the different steps in prokaryotic transcription
Discuss the role of promoters in prokaryotic transcription
Describe how and when transcription is terminated

Genes are turned on and off in many ways. This article covers chemical signal transduction. Article includes animations, pictures, video, biographical information, and quiz questions that are accessed by clicking on buttons along the bottom of the page.