This shows the antibiotics Dalfopristin and Quinupristin, and how their shapes lock into a Ribosome tunnel wall. It shows how two weak drugs can act synergistically to have a lethal effect on bacteria. Here's years of painstaking work displayed in a short animation so simple that even I can understand it. Wonderful. At the smallest level, the shape of the molecule is the shape of the organism. Please Register or Log in to view the hidden image! An article, by the Wolf Chemistry prize winner Ada Yonath, with the forgoing and other great pictures. http://www.weizmann.ac.il/Structural_Biology/Pages/Yonath/00Sc_activities.html Please Register or Log in to view the hidden image! Quinupristin Molecular Diagram
Can't say that this is a favourite chemical, but it has a lovely structure. A bit like Jordan really. Please Register or Log in to view the hidden image! Perfluorooctanic acid PFOA is a toxicant and carcinogen in animals, persistent in the environment, and detected in the blood of general populations in the low parts per billion range where it has been linked to infertility. In people with higher exposures, some studies have associated PFOA exposure with birth defects, increased cancer rates, and changes to lipid levels, the immune system and liver—effects identified in animals. PFOA has been detected in industrial waste, stain resistant carpets, house dust, microwave popcorn bags, water, food, and PTFE. Despite its detection in PTFE, and uncertainty in how people are exposed, non-stick cookware is not thought to be a significant exposure pathway to people. From Wiki Disambiguation: By Jordan, I mean the model, not the Country. Please Register or Log in to view the hidden image! Jordan the model (Not a bad old tart really) Please Register or Log in to view the hidden image! Jordan the Country
Does anyone know which chemicals give wine its various smells and flavours. The grape is indeed a phenomenal chemical factory.
That depends entirely which flavours and smells you're referring to. The smells of most fruits and berries are (IIRC) Esters. However skunks use a Thiol to generate their offensive smell, and the difference between this, the component that gives Garlic its smell, and the component in oninons that make your eyes water is a terminal functional group (There's a thiol, alkene, and an alkane, I know the Skunk is the thiol, but I forget what the other two are).
A lot of stinky chemicals have sulphur in them. Thiols are like alcohols, but with a sulphur instead of oxygen, which is above it in the periodic table. Please Register or Log in to view the hidden image! The skunk smell substitutes Sulphur with Selenium, which is the next one down in the periodic table. Presumably Tellurium and Polonium -ols are pretty stinky too.
This seemed unlikely to me as sulpher is so much more commonly found in the foods a skunks would have access to, like eggs of ground nesting birds. (I bet that skunks can climb trees also - I know a close realtive in Brazil, called "gamba" here can as I shot one out of a tree a few hours after dark.* - It, I think, was eating the eggs my chickens laid.) So I checked. Here is what I found: "... Skunk spray is composed mainly of low molecular weight thiol compounds,[4] namely (E)-2-butene-1-thiol, 3-methyl-1-butanethiol, and 2-quinolinemethanethiol, as well as acetate thioesters of each of these.[5][6] These compounds are detectable {by humans} at concentrations of about 2 parts per million. ..." Please Register or Log in to view the hidden image! From: http://en.wikipedia.org/wiki/Skunk#Anal_scent_glands While learning a little about thiols, I found this cute little dog, called Ethanethiol: Please Register or Log in to view the hidden image! ------------- *It has eyes like a cat -i.e. a reflective layer behind the retina to give photns a second chance to activate a photo sensitive cell. This is at the price of some loss of contrast and resolution as it promotes internal scatering of light, but worth it for night hunters. Humans and most other day creatures had a black absorbing layer behind the retina of their eyes. It stared at me into my flashlight, until the bullet hit.
I Like the dog! Chemistry's alternative to the balloon man. This is the Selenium version of Carbon Dioxide. Carbon Diselenide, an oily disgusting smelling liquid. Please Register or Log in to view the hidden image! This article describes how the manufacture of it in 1936 in a University laboratory led to the evacuation of a nearby village. http://pipeline.corante.com/archives/2005/03/03/things_i_wont_work_with_carbon_diselenide.php
Foxp2 FOXP2, gene on chromosome 7 that regulates tissue growth. Please Register or Log in to view the hidden image! Variations in this gene are also responsible for increased vocalisation in canaries, mice, bats, and apes. Aside from a polyglutamine tract, human FOXP2 differs from chimp FOXP2 by only two amino acids, mouse FOXP2 by only 3 amino acids, and zebra finch FOXP2 by only 7 amino acids.[17][18][19] A recent extraction of DNA from Neanderthal bones indicates that Neanderthals had the same version (allele) of the FOXP2 gene as modern humans.[20] Wiki If we changed those 3 mice aminos, would we get talking mice do you think?
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Ref. post 20, Capsaicin - it is found in red pepers - what makes them so "hot" I am almost certain. There is some evidence it helps with prostate cancer via: "Dissipation of the mitochondrial inner transmembrane potential, activation of caspase-3, induced apoptosis of prostate tumor cells in nude mice." Is this why it is "your favourite molecular structure" ?
As the drooling smiley would indicate, chile is the reason. Big Jim, Sandia, Barker, Sante Fe Yellow, Cascabel, Cayenne, Ancho, etc. The stuff of a happy life. Capsaicin is the 'heat' in various chiles the world over. Not just red peppers.
The burning and painful sensations associated with capsaicin result from its chemical interaction with sensory neurons. Capsaicin, as a member of the vanilloid family, binds to a receptor called the vanilloid receptor subtype 1 (VR1).[34] First cloned in 1997, VR1 is an ion channel-type receptor. VR1, which can also be stimulated with heat and physical abrasion, permits cations to pass through the cell membrane and into the cell when activated. The resulting depolarization of the neuron stimulates it to signal the brain. By binding to the VR1 receptor, the capsaicin molecule produces the same sensation that excessive heat or abrasive damage would cause, explaining why the spiciness of capsaicin is described as a burning sensation. Wiki The seeds are spread by birds, which do not have the receptor which produces the burning. This burning stops unwanted creatures from eating the pepper. The plant is pretending to be a fire. When humans eat it, they produce endorphins, giving a sensation of great pleasure.
Please Register or Log in to view the hidden image! Testosterone Has recently been given a makeover. Previously believed to promote aggression, it is now thought to promote status seeking behaviour, which is more subtle, involving bonding and co-operation. Women given doses of Testosterone play games more fairly. Is this scientific proof of what men have thought for centuries? That women just don't play fair? http://www.telegraph.co.uk/science/...akes-people-more-friendly-and-reasonable.html Please Register or Log in to view the hidden image!
In addition to better known actions, testosterone binds to the androgenic receptors, AR, of prostate cells. It can easily be converted to DHT version which binds about 10 times more strongly to the ARs. When either "ligand" binds, the AR/ligand complex alters it shape and may migrate to the prostate cell nucleus. There this complex attaches to specific sections of the DNA and stimulates mitoses of new prostate cells. This is why men with prostate cancer are normally dosed with some drugs that greatly reduces the production of testosterone (or even castrated when they were not available or still today to reduce the chronic expense of these costly drugs.) At least 5% of your testosterone comes from the adrenal glands, so some of these drugs can be more effective than castration.
Loads of chemists show off their favourite molecules in this video... (then hang them on a chemistry christmas tree) http://www.youtube.com/watch?v=X0hDX7LtSxk
I haven't been here long enough to post images up, but Tetraborane is a lovely molecular structure. Pity that Tetraborane itself is highly toxic, oxidises very quickly and smells rather foul.
Who would forget H2O? We call it the Mickey Mouse structure. Personally I find it cute.Please Register or Log in to view the hidden image! Please Register or Log in to view the hidden image!
Any votes for the Molydenum Nano Hedgehog? Inorganic Chemistry shows the Organics a thing or two. Please Register or Log in to view the hidden image! See http://www.uni-bielefeld.de/chemie/emeriti/ac1-mueller/AMU/n_hall.pdf