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 functions proteins perform in the cell and in tissues
Discuss the relationship between amino acids and proteins
Explain the four levels of protein organization
Describe the ways in which protein shape and function are linked

Explore the relationship between the genetic code on the DNA strand and the resulting protein and rudimentary shape it forms. Through models of transcription and translation, you will discover this relationship and the resilience to mutations built into our genetic code. Start by exploring DNA's double helix with an interactive 3D model. Highlight base pairs, look at one or both strands, and turn hydrogen bonds on or off. Next, watch an animation of transcription, which creates RNA from DNA, and translation, which 'reads' the RNA codons to create a protein.

In this scrollable interactive, the four levels of protein folding are explored in detail by exploring the structure of hemoglobin.

This scrollable interactive explores the different roles that proteins can play in the cell. Categories of proteins covered include transmembrane proteins, proteins that make up molecular machines like cilia and ribosomes, and enzymes. The four levels of protein structure are also discussed.

This scrollable interactive reviews how the information in a messenger RNA (mRNA) molecule is translated to create a functioning protein in prokaryotic cells.

Understandable lessons about numerous aspects about the composition, function, and interactions of proteins. Each starts with an interactive quiz and links to a tutorial.