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1:30 animation As a human embryo develops, its cells become progressively restricted in the types of specialized cells that they can produce. Inner cell mass (ICM) cells of the blastocyst can make any type of body cell. Gastrula-stage cells can give rise to the cells of a given germ layer. Later, cells become even more restricted. For example, the pancreatic bud of the endoderm layer can only make the cells of the pancreas.

This two-minute video provides brief background on the use of zebrafish as a model in studying animal development, before showing a time-lapse sequence of a fertilized zebrafish egg developing into a larva.  The video includes some annotations that help orient the viewer during the time-lapse sequence.  Teachers might want to mute the narration beginning at 0:42 min to avoid giving students too much information.  This phenomenon could stimulate the following driving questions: How does the zebrafish develop from one cell to the many cells that make up the larva? How do the zebrafish cells divide? How are the developing zebrafish cells similar and different from each other? If all cells in the zebrafish develop from the same original cell, then how do some cells develop differently than others? How are cell division and growth related? 

Protein folding and trafficking is essential for normal cell function, and when it goes awry it can lead to various chronic conditions, including fatty liver disease, diabetes, and Parkinson's. The narrative of this case study follows two undergraduate students engaged in a summer research project evaluating the effects of cell stress on cell function and health in the model organism Caenorhabditis elegans (C. elegans).  During the case study, students review animal cell organelle function and then learn about endoplasmic stress and unfolded protein response. Prior knowledge needed for the case is basic animal cell organelles and their functions and use of model organisms in research. The case was designed for a flipped classroom in which students prepare in advance by taking a quiz and watching two videos; a PowerPoint animation is also included.

In 1977, a University of Oxford statistician named Richard Peto pointed out a simple yet puzzling biological fact: We humans should have a lot more cancer than mice, but we don't. Dr. Peto's argument was beguilingly simple. Every time a cell divides, there's a small chance it will gain a mutation that speeds its growth. Cells that accumulate several of these mutations may become cancerous. The bigger an animal is, the more cells it has, and the longer an animal lives, the more times its cells divide. We humans undergo about 10,000 times as many cell divisions as mice - and thus should be far more likely to get cancer.

How are the stages of mitosis related to the creation of identical daughter cells? The primary function of the stages of mitosis is to make certain that each daughter cell is genetically identical to the mother cell. The mother cell's DNA is copied during interphase. During mitosis the chromosomes condense from long strands to highly coiled structures. The two copies of each DNA strand, called sister chromatids, are physically attached to one another. The chromosomes are moved to the center of the cell and split apart in a highly coordinated fashion. The condensation of the chromosomes, the physical connection of the sister chromatids, and the precise movement of the chromosomes are all important in making sure that each daughter cell has one copy of each chromosome and is genetically identical to the mother cell.

Inside the cell: -cell function, -interactive, functions, specialization, mitosis, aging/death, glossary

It's one of the big mysteries of cell biology. Why do mitochondria-the oval-shaped structures that power our cells-have their own DNA, and why have they kept it when the cell itself has plenty of its own genetic material? A new study may have found an answer. Scientists think that mitochondria were once independent single-celled organisms until, more than a billion years ago, they were swallowed by larger cells. Instead of being digested, they settled down and developed a mutually beneficial relationship developed with their hosts that eventually enabled the rise of more complex life, like today's plants and animals.

Explore some examples of specialized plant and animal cells with the Amoeba Sisters! This video explains how specialized cell structure suits their function.

By observing how the cells in the zebrafish's skin responded to injury, the Duke team learned a lot about the skin regeneration process and were surprised by its complexity. They saw that in the hours following a fin amputation, for example, zebrafish regenerated skin through three different mechanisms: the "recruitment" of spare skin cells from other areas, a temporary doubling in size in some pre-existing cells, and the creation of completely new cells.

When a person dies from cancer, the culprit is usually not the original tumor but rather the cancerous cells that spread throughout the body and replicate in distant organs, a process called metastasis. Researchers have long known that metastasizing cancer cells slip their bonds and avoid immune detection by altering the sugars on their surfaces. They've even come up with a would-be drug to prevent such sugar alterations. But that compound interferes with needed sugars on normal cells, too, with lethal results in animals. Now, Dutch researchers report that they've packaged the drug in nanoparticles targeted exclusively to cancer cells, and they've shown that this combination prevents cancer cells from metastasizing in mice.  

"The Inner Life of a Cell, an 3 animation created in NewTek LightWave 3D and Adobe After Effects for Harvard biology students. The animation illustrates unseen molecular mechanisms and the ones they trigger, specifically how white blood cells sense and respond to their surroundings and external stimuli."

Meiosis, the form of cell division unique to egg and sperm production, sets the stage for sex determination by creating sperm that carry either an X or a Y sex chromosome. But what is it about the X or Y that determines sex? Before a meiotic cell divides, its two sets of chromosomes come together and cross over, or swap, segments. The first animation shows normal crossing over, where the X and Y chromosomes exchange pieces only at their tips. The second animation shows a rare mistake in which the Y chromosome transfers a gene called SRY to the X chromosome, resulting in sex-reversed babies. Studies of sex-reversed individuals led researchers to identify the master switch for sex determination, the SRY gene, which tells a fetus to become a boy.

Meiosis, the form of cell division unique to egg and sperm production, sets the stage for sex determination by creating sperm that carry either an X or a Y sex chromosome. But what is it about the X or Y that determines sex? Before a meiotic cell divides, its two sets of chromosomes come together and cross over, or swap, segments. The first animation shows normal crossing over, where the X and Y chromosomes exchange pieces only at their tips. The second animation shows a rare mistake in which the Y chromosome transfers a gene called SRY to the X chromosome, resulting in sex-reversed babies. Studies of sex-reversed individuals led researchers to identify the master switch for sex determination, the SRY gene, which tells a fetus to become a boy.

brief animations vividly illustrating cells and cellular processes

FEBRUARY 20, 2015-A diverse group of experts from academia, industry and advocacy convened by a Georgetown researcher is offering recommendations to the National Institutes of Health (NIH) regarding how to address the overreliance of male cells and animals used in preclinical studies. The recommendations come as the federal research institution works to increase the inclusion of female animal models and achieve a balance in the use of male and female cells and animals in lab research.

An international team led by Professor Itai YanaAi of the Technion-Israel Institute of Technology Department of Biology made the discovery after using an extraordinarily powerful technique known as CEL-Seq. CEL-Seq monitors individual cells for their gene activity (as detected via mRNA)-and they applied it across 10 different species, with CEL-Seq being applied to 70 embryos per species. In particular, they were interested in whether the animal classification of phylum-which separates animals into groups according to their body plans-is actually a useful tool for placing animals into groups, as well as what genetic attributes are the same and different between the different phyla.

The team, led by senior authors Qi Zhou and Xiao-Yang Zhao, both from the Institute of Zoology at the Chinese Academy of Sciences, took embryonic stem cells from mice and treated them to a series of carefully worked out steps that included first exposing the stem cells to testicular cells in newly born male mice. The scientists then recreated the chemical environment that sperm cells need to grow, including early development factors and sex hormones including testosterone, follicle stimulating hormone and a growth factor from the pituitary gland.

Cancer cells are hungry. To feed their rapid growth and division, their metabolism changes. Moreover, they use sugar (glucose) in a different way to normal cells. This animation, created by Nature Reviews Drug Discovery, explores the key aspects of the altered metabolism in cancer cells and explains how these can be exploited for the development of new anticancer strategies.

The team was grafting skin from one strain of mice to another. The new skin tended to get destroyed by the recipient animals' immune systems. But when the group injected cells from the donor mice into developing fetuses, the mice that were born were much more likely to accept the skin graft. It seemed they had been primed to the foreign cells while in the womb, and developed a tolerance.

Animation and self quiz on cell cycle