Biology Dictionary

  • Universal gas constant

    Universal gas constant

    A constant used in equations describing gases, denoted by R, which relates temperature, pressure, and volume in the ideal gas…

  • Universal recipient

    Universal recipient

    A person with blood type AB positive, whose blood can receive donations from any other blood type.

  • Unsaturated

    Unsaturated

    A term describing a compound, such as a fat, that contains one or more double bonds between carbon atoms.

  • Unsaturated fatty acid

    Unsaturated fatty acid

    A type of fatty acid that contains one or more double bonds in its carbon chain, often found in plant…

  • Unsaturated fatty acids

    Unsaturated fatty acids

    Fatty acids that have one or more double bonds in their carbon chains, making them liquid at room temperature.

  • Unwinding proteins

    Unwinding proteins

    Proteins that help separate the strands of DNA during processes such as replication and transcription.

  • Up promoter

    Up promoter

    A DNA sequence located upstream of a gene that helps regulate its transcription by interacting with RNA polymerase.

  • Uracil

    Uracil

    One of the four nucleotide bases in RNA, pairing with adenine during RNA synthesis.

  • Uranium (U)

    Uranium (U)

    A heavy metal element used as a fuel in nuclear reactors and in the production of nuclear weapons, known for…

  • Urea

    Urea

    A compound produced in the liver from ammonia, excreted by the kidneys as a primary nitrogenous waste product in mammals.