This is this collection of lectures for the Intro Bio course taught at Columbia in the 2011-2012 academic year. Lectures 1-23 correspond to the fall semester while 24-48 correspond to the spring semester. Prerequisites: One year of college chemistry, or a strong high school chemistry background. Recommended as the introductory biology course for biology and related majors, and for premedical students. Fundamental principles of biochemistry, molecular biology, and genetics. Cellular biology and development; physiology of cells and organisms. For supplementary materials, please reference the website for the first semester (https://newcourseworks.columbia.edu/access/content/group/BIOLC2005_001_2011_3/indexo.html) and the second semester (https://newcourseworks.columbia.edu/access/content/group/BIOLC2006_001_2012_1/misc2012/main-menu.html). If you have any questions, please contact the course administrator at: pnt2102@columbia.edu