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:

Explain transformation of DNA
Describe the key experiments that helped identify that DNA is the genetic material
State and explain Chargaff’s rules

Enzymes, nature's catalysts, are remarkable biomolecules capable of extraordinary specificity and selectivity. Directed evolution has been used to produce enzymes with many unique properties, including altered substrate specificity, thermal stability, organic solvent resistance, and enantioselectivity--selectivity of one stereoisomer over another. The technique of directed evolution comprises two essential steps: mutagenesis of the gene encoding the enzyme to produce a library of variants, and selection of a particular variant based on its desirable catalytic properties. In this course we will examine what kinds of enzymes are worth evolving and the strategies used for library generation and enzyme selection. We will focus on those enzymes that are used in the synthesis of drugs and in biotechnological applications. This course is one of many Advanced Undergraduate Seminars offered by the Biology Department at MIT. These seminars are tailored for students with an interest in using primary research literature to discuss and learn about current biological research in a highly interactive setting. Many instructors of the Advanced Undergraduate Seminars are postdoctoral scientists with a strong interest in teaching.

In this course, we will discuss the microbial physiology and genetics of stress responses in aquatic ecosystems, astrobiology, bacterial pathogenesis and other environments. We will learn about classical and novel methods utilized by researchers to uncover bacterial mechanisms induced under both general and environment-specific stresses. Finally, we will compare and contrast models for bacterial stress responses to gain an understanding of distinct mechanisms of survival and of why there are differences among bacterial genera.