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  2. Nucleophile - Wikipedia

    en.wikipedia.org/wiki/Nucleophile

    A hydroxide ion acting as a nucleophile in an S N 2 reaction, converting a haloalkane into an alcohol. In chemistry, a nucleophile is a chemical species that forms bonds by donating an electron pair. All molecules and ions with a free pair of electrons or at least one pi bond can act as nucleophiles. Because nucleophiles donate electrons, they ...

  3. Chemical reaction - Wikipedia

    en.wikipedia.org/wiki/Chemical_reaction

    The electron pair from the nucleophile attacks the substrate forming a new bond, while the leaving group departs with an electron pair. The nucleophile may be electrically neutral or negatively charged, whereas the substrate is typically neutral or positively charged. Examples of nucleophiles are hydroxide ion, alkoxides, amines and halides.

  4. Azide - Wikipedia

    en.wikipedia.org/wiki/Azide

    However, it has the disadvantage to be prone to trigger unexpected and undesirable side reactions that can jeopardize the experimental results. Indeed, the azide anion is a nucleophile and a redox-active species. Being prone to disproportionation, it can behave both as an oxidizing and as a reducing agent. Therefore, it is susceptible to ...

  5. Catalytic triad - Wikipedia

    en.wikipedia.org/wiki/Catalytic_triad

    The nucleophile is polarised and oriented by the base, which is itself bound and stabilised by the acid. [24] Catalysis is performed in two stages. First, the activated nucleophile attacks the carbonyl carbon and forces the carbonyl oxygen to accept an electron pair, leading to a tetrahedral intermediate. The resulting build-up of negative ...

  6. Biological roles of the elements - Wikipedia

    en.wikipedia.org/wiki/Biological_roles_of_the...

    A large fraction of the chemical elements that occur naturally on the Earth's surface are essential to the structure and metabolism of living things. Four of these elements (hydrogen, carbon, nitrogen, and oxygen) are essential to every living thing and collectively make up 99% of the mass of protoplasm. [1]

  7. Woman Paralyzed by Falling Tree Can Move Again Thanks to ...

    www.aol.com/woman-paralyzed-falling-tree-move...

    Jessie Owen was traveling with her family twelve years ago when, while going through a mountain pass, a tree fell on their car. “In that moment, my parents passed away, my siblings were severely ...

  8. Function (biology) - Wikipedia

    en.wikipedia.org/wiki/Function_(biology)

    In evolutionary biology, function is the reason some object or process occurred in a system that evolved through natural selection. That reason is typically that it achieves some result, such as that chlorophyll helps to capture the energy of sunlight in photosynthesis .

  9. Dying To Be Free - The Huffington Post

    projects.huffingtonpost.com/dying-to-be-free...

    In AA, the definition of insanity is doing the same thing over and over again and expecting a different result. They should think about that.” Over more than a decade prescribing Suboxone in his private practice, Kalfas said, none of his patients have fatally overdosed on heroin, with fewer than 20 percent dropping their prescription and ...