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:

Understand how the cell cycle is controlled by mechanisms that are both internal and external to the cell
Explain how the three internal “control checkpoints” occur at the end of G1, at the G2/M transition, and during metaphase
Describe the molecules that control the cell cycle through positive and negative regulation

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

Describe the three stages of interphase
Discuss the behavior of chromosomes during karyokinesis/mitosis
Explain how the cytoplasmic content is divided during cytokinesis
Define the quiescent G0 phase

The Cell Biology Project at the University of Arizona provides an explanation of mitosis, DNA basics, diagrams and a practice exercise.

This pathway provides an introduction to the cell cycle and how its regulation is important to normal cell division. Cancer is often caused by unregulated cell division. For a deeper look at this topic, we recommend the pathway Cell Reproduction from the OpenStax textbook Biology for AP® Courses.

Poses and answers the question, "What is (and is not) mitosis?" An overview with images of the phases of mitosis, plus a mitosis animation.

This animated explanation introduces the concept of mitosis by reviewing the research of Walther Flemming.

Theodore Boveri will describe his research with worms that helped him discover the principles of meiosis. The animations of meiosis are really good.

This cell biology lesson explains and illustrated the different phases of meiosis. Includes vocabulary and assessment links as well as othe related resources.

Online mitosis activity offers the student the opportunity to identify, classify, calculate, and graph the phases of mitosis. Explanations of each phase, actual cells are displayed for classifing and gathering data in this comprehensive tutorial.

Read a brief introduction to mitosis, and then click on the 5 phases to read details and view photos of each in progress. Photo examples are excellent.