Group items tagged

It's peak cold and flu season, and mucus is making many of our lives miserable. But despite being a little icky, phlegm gets a bad rap. This germ-fighting goo contains cells and chemical compounds that help us power through a cold. You can also think of mucus as a traffic light for your health - what turns up in our used tissues can be a useful clue about the inner workings of our immune systems.

In this classroom activity, there are chemical formulas and 3-D structural diagrams of some interesting natural and artificial molecules that students can build with a kit. To build some models, students will have to team up with one or more colleagues.

Quick look: In its modern sense, epigenetics is the term used to describe inheritance by mechanisms other than through the DNA sequence of genes. It can apply to characteristics passed from a cell to its daughter cells in cell division and to traits of a whole organism. It works through chemical tags added to chromosomes that in effect switch genes on or off.

Graham Williams at the University of Huddersfield, UK, has a different way - to look for modifications to the twins' DNA that have come about as a result of their lifestyles. Such epigenetic changes occur when a chemical group known as a methyl group attaches to a gene and modifies the way it is expressed. This happens as a body is influenced by a person's environment, lifestyle and disease.

Whether gas, liquid or solid; radioactive or stable; reactive or inert; toxic or in your vitamin pill, the 118 building blocks each has its own chemically idiosyncratic characteristics--and certain commonalities. See what makes your favorite element unique on this interactive periodic table

The early stages of embryonic development shape our cells and tissues for life. It is during this time that our newly formed cells are transformed into heart, skin, nerve or other cell types. Scientists are finding that this process is largely controlled not by the genome, but by the epigenome, chemical markers on DNA that tell cells when to turn genes on and off. Now, studying zebrafish embryos, researchers at Washington University School of Medicine in St. Louis have shown that the epigenome plays a significant part in guiding development in the first 24 hours after fertilization.

This two minute animation describes the Octet Rule and explains the difference between ionic and covalent bonds.

Mr. Andersen shows you how to determine if a bond is nonpolar covalent, polar covalent, or ionc.

3:47 video: Vinegar may have a powerful smell, but did you know it's actually a weak acid? In the chemical economy, acids actively give away their protons while bases actively collect them -- but some more aggressively than others. George Zaidan and Charles Morton use the currency of subatomic particles to explain this unseen exchange.

The possibilities of pseudo-peptide-DNA mimics like PNA (peptide nucleic acid) having a role for the prebiotic origin of life prior to an RNA world is discussed on the basis of literature data showing that this type of molecules might have formed on the primitive earth (or other places in the universe), as well as data indicating the possibilities of template-directed PNA chemical replication and ligation. In particular, the merits of an achiral prebiotic genetic material is discussed.

The study is the first to find that people's bodies metabolize bisphenol-A (BPA) - a chemical found in most people and used in polycarbonate plastic, food cans and paper receipts - into something that impacts our cells and may make us fat. The research, from Health Canada, challenges an untested assumption that our liver metabolizes BPA into a form that doesn't impact our health.

New research shows butterflies use nectar to drug unsuspecting ants with mind-altering chemicals. The Japanese oakblue butterfly (Narathura japonica) enlists the help of ants (Pristomyrmex punctatus) to stand guard and protect its growing caterpillars (pictured) from predators such as wasps and spiders.

This case study is used to teach undergraduate students about hydraulic fracturing (hydrofracking), a controversial method for extracting methane from shale. The controversy arises from claims that chemicals used in the fracking process and the methane itself find their way into drinking water and are also sometimes found at dangerous levels in the air. The case study begins in a college chemistry class where a student inquires about a news item he saw about residents setting their tap water on fire. The instructor uses this as an opportunity for the students to research hydrofracking and natural gas, and she then integrate these topics into their present study of isotopes. The class first examines what isotopes are by using a guided inquiry based activity. The students then learn how mass spectrometry, which uses the principles just learned about isotopes, is employed to determine the source of methane in contaminated wells. This case study is designed for freshman chemistry students and students in environmental studies.

The Hawaiian Bobtail squid has a remarkable symbiotic relationship with a species of marine bacteria that can produce light by a controlled chemical reaction. Also featured on the HHMI DVD, Exploring Biodiversity: The Search for New Medicines, available free from HHMI.

Neutrophils are our body's first line of defense against bacterial infections. After leaving nearby blood vessels, these cells recognize chemicals produced by bacteria in a cut or scratch and migrate "toward the smell". The above neutrophils were placed in a gradient of fMLP (n formyl methionine- leucine- phenylalanine), a peptide chain produced by some bacteria. The cells charge out like a "posse" after the bad guys.

2 min -intro overview Chemical reactions need a catalyst to provide a site for the reaction and control the energy flow. Catalysts are made up of enzymes.

By analyzing the chemical signatures of six coral reef cores taken from multiple sites in the Pacific Ocean around Panama, the scientists found an extreme weather event associated with what we would call La Niña today triggered the reef collapse. A series of events similar to El Niño continued to suppress the reef for the next two millenniums.

The mouse is the leading organism for disease research. A rich resource of genetic variation occurs naturally in inbred and special strains owing to spontaneous mutations. However, one can also obtain desired gene mutations by using the following processes: targeted mutations that eliminate function in the whole organism or in a specific tissue; forward genetic screens using chemicals or transposons; or the introduction of exogenous transgenes as DNAs, bacterial artificial chromosomes (BACs) or reporter constructs. The mouse is the only mammal that provides such a rich resource of genetic diversity coupled with the potential for extensive genome manipulation, and is therefore a powerful application for modeling human disease.

This case study examines a variety of biological factors that may have been involved in the 2013 dolphin "unusual mortality event" (UME) on the East Coast of the United States. The story follows a news reporter and four different scientists who are preparing their notes for speaking at a public hearing about the dolphin die-off event. After reading the story, students assume the roles of these scientists and use the jigsaw method to gather, analyze, and share information.  Due to the interdisciplinary nature of environmental toxicology, this case study exposes students to four main topics: ecology of ecosystems, endocrine system/chemical messaging, immune system function, and virus biology.

An example of natural selection is the frequently observed phenomenon of insecticide resistance in pest insects. Consider what happens when a pest insect population is sprayed for the first time with a chemical insecticide.