Learn how apoptosis is different from cell death by injury. Learn the role of this process in development and body maintenance. [10:48]

Khan Academy learning modules include a Community space where users can ask questions and seek help from community members. Educators should consult with their Technology administrators to determine the use of Khan Academy learning modules in their classroom. Please review materials from external sites before sharing with students.

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 how signaling pathways direct protein expression, cellular metabolism, and cell growth
Identify the function of PKC in signal transduction pathways
Recognize the role of apoptosis in the development and maintenance of a healthy organism

Video lesson presents an introduction to what cancer is and how it is the by-product of broken DNA replication. [12:35]

Khan Academy learning modules include a Community space where users can ask questions and seek help from community members. Educators should consult with their Technology administrators to determine the use of Khan Academy learning modules in their classroom. Please review materials from external sites before sharing with students.

This multimedia article includes animations, pictures, video, biographical information, and quiz questions that are accessed by clicking on buttons along the bottom of the page. The topic is the study of cell division, mitosis, and cell death.

Article discusses how objects in nature are held together through balanced forces. Scroll midway down to find info on microtubules and microfilaments. Links to excellent electron micrographs.