This 11-page Biology course handout gives a detailed explanation of cell structure, supplemented by many illustrations.

Discusses the discovery of centrosomes, their important role in mitosis in animal cells, and their other functions.

Article looks at different types of receptors and ligands, seeing how they interact to turn information from outside the cell into a change inside the cell.

The parts of an animal cell are presented with descriptions of each of its organelles.

Describes the structure and functions of the mitochondria.

Presents information about lysosomes and offers analogies to help students recall their functions in a cell.

Tutorial on DNA basics that goes along with an online quiz over the material. Use the naviagation buttons at the bottom of the page to go to the quiz over the material.

This comprehensive study guide covers the main terms and concepts needed for a unit on the female reproductive system.

The Casparian strip is found in the endodermis layer of a plant's roots and it assists the plant in absorbing water and nutrients from the soil. The structure of a plant root is described and the process by which the Casparian strip...

This site explores the history and the science of DNA. Content also examines and considers the possibilities of genetic engineering and mutation.

Bobbi Seleski catalogs biology from our body and beyond, tracking how unicellular organisms, tissues, organs, organ systems, organisms, populations, communities, ecosystems, and our biosphere build off of each other and work together....