Science / Biology / Epidermis: 1. The outermost layer of skin consisting of several layers of epithelial cells&emdash;notably, keratinocytes&emdash;and, in the inner layer of the epidermis, basal cells and melanocytes. 2. The outer layer of cells in the plant body, often covered by a waxy cuticle.
Science / Biology / Melanin: A pigment that gives the skin color and protects the underlying layers against damage by ultraviolet light; produced by melanocytes in the inner layer of the epidermis. MORE
Science / Biology / Plastids: Membrane-bound organelles in plant cells that function in storage (of food or pigments) or food production. Term for any double membrane-bound organelle. Chloroplasts contain the chemicals for photosy MORE
Science / Biology / Palisade: Layer of mesophyll cells in leaves that are closely placed together under the epidermal layer of the leaf. Palisade parenchyma: Columnar cells located just below the upper epidermis in leaves the cell MORE
Science / Biology / Stomata: Pores on the underside of leaves that can be opened or closed to control gas exchange and water loss. Openings in the epidermis (usually of the leaf) that allow gas exchange. MORE
Science / Biology / Cortex: 1) The outer part of an organ, e.g., the adrenal cortex, which produces several steroid hormones; 2) in plants, the region of the stem or root between the epidermis and the vascular bundle(s). MORE