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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 are Lewis bases. Nucleophilic describes the affinity of a nucleophile to bond with positively charged ...
The list of organisms by chromosome count describes ploidy or numbers of chromosomes in the cells of various plants, animals, protists, and other living organisms.This number, along with the visual appearance of the chromosome, is known as the karyotype, [1] [2] [3] and can be found by looking at the chromosomes through a microscope.
The clan contains both cysteine and serine proteases (different nucleophiles). [1] [2] PA clan proteases can be found in plants, [3] animals, [3] fungi, [3] eubacteria, [4] archaea [5] [6] and viruses. [2] The common use of the catalytic triad for hydrolysis by multiple clans of proteases, including the PA clan, represents an example of ...
Plant FMO's play a role in defending against pathogens and catalyze specific steps in the biosynthesis of auxin, a plant hormone. Plant FMO's also play a role in the metabolism of glucosinolates . These non-xenobiotic roles of plant FMO's suggest that other FMO functions could be identified in non-plant organisms.
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 ...
annual: a plant species that completes its life cycle within a single year or growing season; basal: attached close to the base (of a plant or an evolutionary tree diagram) climber: a vine that leans on, twines around or clings to other plants for vertical support; deciduous: falling seasonally, as with bark, leaves or petals
This is because α-nucleophiles showing the α-effect have smaller HOMO(nucleophile)-LUMO(substrate) gap, in other words, high HOMO energy level that allows more orbital interaction. Examples of α-nucleophiles with α-effects are shown in Figure 4. The α-nucleophiles have smaller HOMO lobes than the parent normal nucleophile. Figure 4.
For example, most plants are photolithoautotrophic, since they use light as an energy source, water as electron donor, and CO 2 as a carbon source. All animals and fungi are chemoorganoheterotrophic , since they use organic substances both as chemical energy sources and as electron/hydrogen donors and carbon sources.