Group items tagged

How does it spread? The Varroa mite carries the disease, feeding on bee larvae, then the virus itself kills off the bees. The study's lead author, Dr. Lena Wilfert, of the University of Exeter's Centre for Ecology and Conservation, said they found evidence that human involvement has played a key role in the epidemic.

The Center for Science in the Public Interest (CSPI) has made a name for itself by tackling the food industry's big guns on everything from artery-furring entrees to misleading label claims. But where does it stand on genetically modified organisms (GMOs)? Elaine Watson quizzed Gregory Jaffe, CSPI director of biotechnology, on everything from GM labeling initiatives to super weeds…

You have probably had the burning sensation of eating a jalapeno or other tear-inducing pepper. What causes this painful fire in your mouth? The short answer is capsaicin. But what exactly is capsaicin? How does it work? Why do people drink milk to relieve the pain? Reactions has the chemistry to answer all of these sizzling questions.

And no copycat is stranger or more accomplished than the mimic octopus. True to its name, it impersonates a variety of other animals on the fly, morphing from an octopus to a banded sole to a lionfish to a sea snake. But this is no random assemblage of impressions: All of these creatures are toxic or venomous.

You will learn about "Dalton's Atomic Theory" in this video. John Dalton was an English chemist who is very well known today for his work in the development of atomic theory. Let us learn the postulates of Dalton's atomic theory. All matter, whether an element, a compound or a mixture are made up of very tiny particles called atoms. All atoms of a given element are identical in size, mass and chemical properties. Atoms of different elements differ in size, mass and chemical properties. Atoms are indivisible particles which can neither be created nor destroyed in a chemical reaction. Atoms combine together in fixed whole number ratios to form compounds. In a chemical reaction, atoms only get rearranged. An atom of an element does not change into the atom of another element.

Why does a snake have 25 or more rows of ribs, whereas a mouse has only 13? The answer, according to a new study, may lie in "junk DNA," large chunks of an animal's genome that were once thought to be useless. The findings could help explain how dramatic changes in body shape have occurred over evolutionary history. Scientists began discovering junk DNA sequences in the 1960s. These stretches of the genome-also known as noncoding DNA-contain the same genetic alphabet found in genes, but they don't code for the proteins that make us who we are. As a result, many researchers long believed this mysterious genetic material was simply DNA debris accumulated over the course of evolution. But over the past couple decades, geneticists have discovered that this so-called junk is anything but. It has important functions, such as switching genes on and off and setting the timing for changes in gene activity. 

Scientists and healthcare professionals initially exhibited little concern over the Zika virus even after evidence of human infection was first identified in 1952; Zika appeared to be both rare and unassociated with morbidity or mortality. Around 2015 all of this changed as journalists, scientists, public health officials, and laypeople scrambled to learn about its varied modes of transmission and devastating consequences (e.g., birth defects and autoimmune disorders). Although research continues to rapidly evolve, this case study directs students to reliable scientific sources (e.g., Centers for Disease Control and World Health Organization) that will likely continue to provide the most current information in order to explore questions such as: Where did the virus come from? How does it spread? What can we do to prevent it? Students will also consider the public health challenges and possible solutions associated with emerging infectious diseases. The case was originally written for an upper-level biology or public health course in which students already have some basic background knowledge regarding viruses, vaccines, and infectious disease.

This case is an account of the events that led Drs. Robin Warren and Barry Marshall to the bacterial theory of ulcers. The two physicians refused to accept the standard explanations for what they had observed and instead developed an alternative hypothesis, saving countless patients from unnecessary pain and suffering. Along the way they transformed the way the medical community viewed peptic ulcer disease. The case shows the importance of curiosity, serendipity, and tenacity in scientific inquiry; how science is built upon the work of others; how assumptions can cloud people's views, leaving them closed to new ideas; and how scientific "truth" can and does change when faced with new data and new interpretations. It is appropriate for use in any course at the high school or undergraduate level that teaches students about the scientific method and/or the sociology, nature, and history of science.

Perhaps the biggest misconception is that as long as you lose weight, it doesn't matter what you eat. But it does. Yet being thin and being healthy are not at all the same thing. Being overweight is not necessarily linked with disease or premature death. What you eat affects which diseases you may develop, regardless of whether you're thin or fat.

When it's completely unraveled, DNA is known to extend approximately six feet in length, yet is somehow able to cram itself into a cell's nucleus. In a study published today (July 27) in Science, researchers created a novel visualization method that revealed a 3-D glimpse of chromatin as it sits jam-packed within the nuclei of human cells. The researchers found that, contrary to how it's depicted in most textbooks, chromatin does not fold in on itself in an organized manner to create distinct structures. Instead, it forms a pliable, inconsistent chain characterized by a wide variety of folding patterns. 

What does it mean to be 'alive'? At a basic level, viruses are proteins and genetic material that survive and replicate within their environment, inside another life form. In the absence of their host, viruses are unable to replicate and many are unable to survive for long in the extracellular environment. Therefore, if they cannot survive independently, can they be defined as being 'alive'?

This directed case study follows the story of "Pauline," a 20-year-old college student who has just received results from a personal genetic testing kit she purchased online. The report shows a negative result for variants of the BRCA 1 and 2 genes, which are associated with a greater risk for breast cancer. Although Pauline has a family history of breast cancer, she concludes that she no longer needs to be concerned, or does she? As students work through the questions in this case study, they review the role of genes and how they code for proteins as well as the effects of proteins on health, especially on cellular growth regulation and cancer. They also learn about the process of genetic testing and consider the ramifications of positive and negative tests for diseases or health conditions, especially with respect to breast cancer. The case is designed for non-science majors in a scientific methods course and could also be used in an introductory biology course. The questions in the case could be adapted for an upper level genetics class.

On July 26, 1943, Los Angeles was blanketed by a thick gas that stung people's eyes and blocked out the Sun. Panicked residents believed their city had been attacked using chemical warfare. But the cloud wasn't an act of war. It was smog. So what is this thick gray haze actually made of? And why does it affect some cities and not others? Kim Preshoff details the science behind smog.

our circadian rhythm can be interrupted from the light emitted from your phone, but how? What is it doing to your brain? What Sleep Deprivation Does To Your Body - https://youtu.be/lfmy0d9oWt8

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? 

You're swimming in the ocean when something brushes your leg. When the tingling sets in, you realize you've been stung by a jellyfish. How do these beautiful gelatinous creatures pack such a painful punch? Neosha S Kashef details the science behind the sting.

It's an inevitable side effect of longevity: your hair will turn gray. In this episode, Sophia Cai chats about the chemistry of your natural hair color, why it eventually turns white, and how scientists may be able to slow that graying down.

In our first animation of this series we learned how point mutations can edit genetic information. Here we see how duplication events can dramatically lengthen the genetic code of an individual. As point mutations add up in the duplicated region across generations, entirely new genes with new functions can evolve. In the video we see three examples of gene duplications resulting in new traits for the creatures who inherit them: the evolution of a venom gene in snakes, the evolution of leaf digestion genes in monkeys, and the evolution of burrowing legs in hunting dogs.

article addresses student question, "Why do cells use uracil, when thymine is already available?"