Biology Dictionary

  • Penetrance

    Penetrance

    The proportion of individuals with a particular genetic mutation who exhibit the associated phenotype.

  • Pennate

    Pennate

    Describing a type of leaf or feather with a central axis and smaller structures (leaflets or barbs) branching off.

  • Penniform

    Penniform

    Resembling a feather in shape or structure, typically referring to muscles or feathers.

  • Pennsylvania period

    Pennsylvania period

    The final period of the Paleozoic era, lasting from approximately 323 to 299 million years ago.

  • Pep

    Pep

    An abbreviation for ‘peptide,’ referring to a short chain of amino acids.

  • PEPC

    PEPC

    Phosphoenolpyruvate carboxylase, an enzyme that catalyzes the conversion of phosphoenolpyruvate to oxaloacetate in plants.

  • PEPCK

    PEPCK

    Phosphoenolpyruvate carboxykinase, an enzyme involved in gluconeogenesis and the regulation of glucose production in the liver.

  • Pepsin

    Pepsin

    A digestive enzyme found in the stomach that breaks down proteins into smaller peptides.

  • Passive transport

    Passive transport

    The movement of substances across a cell membrane without the use of energy, such as diffusion or osmosis.

  • Pathogen

    Pathogen

    An organism, such as a bacterium, virus, or fungus, that causes disease in its host.