Dictionary > Zwitterion

Zwitterion

Definition
noun, plural: zwitterions
A molecule carrying both a positive and a negative charge
Supplement
A zwitterion is a molecule that has both positive and negative charges. It is made up of two (or more) functional groups. One of its components has a positive charge and another one with a negative charge. Because of this, the net charge of a zwitterion is zero. The presence of the opposing charges in the same molecule balances each one out resulting in the molecule becoming electrically neutral.
Examples of zwitterions are amino acids. An amino acid has two functional groups: amine group and a carboxylate group, along with a side chain group (R group). At pH of 2.2 to 9.4, the amino acid is in a zwitterion state (i.e. with a negative carboxylate group and a positive α-ammonium group) and therefore with a net zero charge. However, at pH below 2.2, the amino acid would have a net charge of +1 as the predominant form would have a positive α-ammonium ion and a neutral carboxylic acid. At pH above 9.47, it would have a net charge of -1 as the predominant form would have a negative carboxylate and neutral α-amino group.
Word origin: German zwitter (“hermaphrodite”) + ion
Synonym(s):

  • dipolar ion

See also:

  • amino acid


  • You will also like...

    New Zealand Flora & Fauna
    Ecology & Biodiversity: New Zealand Flora & Fauna

    New Zealand is known for its unique biodiversity, caused by its remarkable geography and geologic history. Breaking away..

    mRNA
    Protein Synthesis

    Part of the genetic information is devoted to the synthesis of proteins. mRNA, a type of RNA, is produced as a transcri..

    Plant Auxins
    Plant Auxins – Phototropism & Geotropism

    Plants produce hormones to regulate their growth. Auxins, for instance, influence plant growth. Know the role of auxin i..

    Neural Control Mechanisms
    Neural Control Mechanisms

    Neurons generate electric signals that they pass along to the other neurons or target tissues. In this tutorial, you wil..

    Ecological Research Measuring & Analysis
    Ecological Research: Measuring & Analysis

    This lesson is about the methods used for ecological research, such as quadrat and transect sampling, canopy fogging, an..

    Digestion and Absorption of Food
    Digestion and Absorption of Food

    The gastrointestinal system breaks down particles of ingested food into molecular forms by enzymes through digestion and..

    Related Articles...

    No related articles found

    See all Related Topics