Khan Academy
Khan Academy: Cell Cycle Checkpoints
Learn how cells use checkpoints to regulate the cell cycle. This article provides an overview of cell cycle control, outlining the factors that influence a cell's decision to pause or progress at each checkpoint.
CK-12 Foundation
Ck 12: Life Science: 2.20 Cell Cycle
Understand the life cycle of a eukaryotic cell.
PBS
Nova Online: How Cells Divide, Mitosis vs. Meiosis
Slideshow of mitosis and meiosis side-by-side. It is a summation of the two processes and the differences between them are clear.
City University of New York
Brooklyn College: The Cell Cycle: Naming the Parts
Use this information to help you understand the differences between major parts of the cell cycle. A good place to start a study of cell division.
University of Arizona
University of Arizona: Cell Cycle and Mitosis Tutorial
Has explanations, illustrations, and a Quick Time movie to download. Also contains practice test questions that are answered online.
University of Arizona
U of a Biology Project: Cell Cycle and Mitosis Tutorial
Poses and answers the question, "What is (and is not) mitosis?" An overview with images of the phases of mitosis, plus a mitosis animation.
Khan Academy
Khan Academy: Apoptosis
Learn about programmed cell death and how it is different from necrosis, cell death due to injury.
Biology Pages
Kimball's Biology Pages: Dna Replication
This page provides a fairly high level explanation of DNA replication with extensive graphics. Good description of this process.
Khan Academy
Khan Academy: Test Prep: Mcat: Oxidative Phosphorylation: The Major Energy Provider of the Cell
Explains oxidative phosphorylation, which is the fourth step of cellular respiration, and produces the most of the energy in cellular respiration.
City University of New York
The World of Cells: Viruses
Alive or not, viruses are introduced in an easy to follow essay that explains many basic concepts.
BiologyWise
Biology Wise: Cellular Respiration in Plants
Explains what cellular respiration is, its function, and the three stages it goes through when it takes place in a cell.
PBS
Pbs Learning Media: Duck Development
This video segment from NOVA: "The Shape of Things" follows the growth of a duck embryo, from a single fertilized egg cell to a complex, hatching duckling. [2:43]
Khan Academy
Khan Academy: Regulation of Cellular Respiration
This article investigates how cellular respiration can be sped up or slowed down in response to ATP levels and other metabolic signals.