What is meant by “polarity” of a polypeptide chain and by “polarity” of a chemical bond?

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  • What is meant by “polarity” of a polypeptide chain and by “polarity” of a chemical bond?


Answer #1 | 14/01 2014 13:12
The polarity of a polypeptide chain refers to whether or not the polypeptide chain has elements within it, specifically, within the R group of the amino acids within the polypeptide chain, that have electronegativity: such as nitrogen, oxygen, fluorine, etc. For example, a polypeptide chain containing only glycine (glycine has an R group of only hydrogen and is a non polar amino acid) makes the polypeptide less polar than a polypeptide chain with R groups of asparagine or glutamine (which are polar) amino acids would be a much more polar amino acid in comparison. When speaking of the polarity of a chemical bond this is referring to the tendency to find the electrons shared in the bond closer to one atom or element versus the other element to which it is bound. For example, water H---O---H has 2 very polar chemical covalent bonds due to the electronegativity of oxygen, In the water molecule the electrons are "pulled" towards the oxygen atom, thus giving the oxygen atom a partial negative charge and the hydrogens a partial positive charge. The definition of bond polarity is the unequal distribution of charge (i.e electrons) within a molecule. In water, there is an unequal distribution of charge because the electrons are more attracted to oxygen than to hydrogen. Hope this helps. :)
Positive: 66.666666666667 %
Answer #2 | 15/01 2014 11:54
The "polarity" refers to the charge of the molecule. E,g, - hydrogen molecules will have a positive charge because they are H+ ions. Similarly, OH ions will have a negative charge because they are OH-
Positive: 33.333333333333 %

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