Biology Dictionary

  • Jh

    Jh

    Abbreviation for juvenile hormone, which regulates development and metamorphosis in insects.

  • Joule (j)

    Joule (j)

    The SI unit of energy, equal to one newton-meter.

  • Jugum

    Jugum

    A structure that connects forewings and hindwings in some insects, aiding in synchronized flight.

  • Jumping genes

    Jumping genes

    Transposable elements or DNA sequences that can change position within the genome.

  • Junk dna

    Junk dna

    Non-coding DNA sequences once thought to have no function but now known to play regulatory roles.

  • Jurassic period

    Jurassic period

    A geologic period from about 201 to 145 million years ago, known for the abundance of dinosaurs.

  • Juvenile hormones

    Juvenile hormones

    Hormones in insects that regulate development, reproduction, and metamorphosis.

  • K

    K

    Symbol for the element potassium or for kelvin, the SI unit of temperature.

  • Kappa particles

    Kappa particles

    Cytoplasmic elements in *Paramecium* associated with the production of toxins that kill sensitive strains.

  • Karyokinesis

    Karyokinesis

    The process of nuclear division in a cell, especially during mitosis or meiosis.