The Oedogoniales are remarkable filamentous green algae. Their method of cell elongation is unique, utilizing a donut-shaped ring of soft wall material which is stretched to form the new daughter cell. While Oedogonium is a simple filament, the related Bulbochaete and Oedocladium are branched and Bulbochaete differentiates long hair cells. The zoospore is large and multiflagellated. Sexual reproduction is oogamous and either “macrandrous” or “nannandrous.”...

Diatoms are an extraordinarily successful group of organisms and their many thousands of species have diversified and specialized so as to occupy every environmental niche. Part of their success derives from their unique protective cell walls, beautifully elaborate structures made of pure silica. However, living inside walls made of this rigid, refractory material creates many problems. Just how diatoms circumvent these problems provides the major...

Combining images of living plant stages with computer simulations allows you to easily bridge the gap between the familiar plant and the micro-environment contained within it. Three dimensional animations take you in and around reproductive structures such as the sorus, sporangium, and antheridium and archegonium. You see dynamic events such as spore formation, spore release, prothallus formation, sperm release, fertilization and embryo growth..

For convenience, biologists divide living organisms into five “Kingdoms”: the Monerans (bacteria and cyanobacteria), Protists, Fungi, Plants, and Animals. The Kingdom Protista includes a vast array of tiny eukaryotic cells that lead complex and extraordinary lives far from the eyes of most humans; a dedication to microscopy is vital to see them in all their splendor. This video is a unique resource introducing the viewer to a considerable range...

Living Cells features greatly expanded coverage of subject matter and extensive additional footage when compared to the original video tape of 1992. The vivid, high-magnification images introduce students to a variety of cells, cellular activities, and subcellular organelles. The video is organized into 24 chapters on specific topics such as actin, microtubules, and flagella.. The Living Cells video offers a most convenient way of accessing beautiful...

The Volvocales and Chlorococcales share a common ancestry from a cell type exemplified by Chlamydomonas. Using live cells, this video shows how simple evolutionary trends working on Chlamydomonad ancestors have generated diversity and complexity.. In Volvocalean evolution, unicellular ancestors became multicellular (e.g., Volvox) by daughter cells adhering after division. Concurrently, they evolved various advanced characters (e.g., differentiation...

Reproduction in the red algae is unique. No flagellated stages are ever formed, and it is generally assumed that the various reproductive spores are inert. This video demonstrates that spores in many species are actively motile, either by gliding or amoeboid activity. This limited power of movement may turn out to be of considerable significance in survival strategies (e.g. dispersion, optimization of a germination site).. Sexual reproduction is also...

Cellular communication depends on specific molecular interactions, where the message and the receiver are biomolecules. Follow this process for signaling molecules such as the hormones epinephrine, adrenalin, and epidermal growth factor, which stimulates cells to divide. Cellular signaling is like the children's game called telephone, except the message is usually conveyed accurately!

Examine the cell cycle of eukaryotic cells and the cycle's effect on DNA replication. Discover that a quirk in the copying of linear DNA leads to the shrinking of chromosomes as cells age, a problem reversed in egg and sperm cells by the telomerase enzyme. For this reason, telomerase might appear to be the secret to immortality except its unregulated presence in cells can lead to cancer.

The word "cholesterol"_x009d_ evokes fear in anyone worried about coronary artery disease. But what is this ubiquitous lipid and how harmful is it? Examine the key steps in cholesterol synthesis, learn about its important role in membranes, and discover where LDLs ("bad"_x009d_ cholesterol) and HDLs ("good"_x009d_) come from. It isn't cholesterol alone that is plugging arteries in atherosclerosis.