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jejunum The second portion of the small intestine. Also, a popular month for weddings!
Jurassic Period Middle period of the Mesozoic Era, between 185-135 million years ago. Characterized by the (possible) origin of angiosperms and the continued split of the worldwide supercontinent of Pangaea.
karyotype The chromosomal characteristics of a cell; also, a representation of the chromosomes aligned in pairs.
keratin A Şbrous protein that Şlls mature keratinocytes near the skin's surface.
keratinocytes The basic cell type of the epidermis; produced by basal cells in the inner layer of the epidermis.
kidney stones Crystallized deposits of excess wastes such as uric acid, calcium, and magnesium that may form in the kidney.
kilocalorie The energy needed to heat 1000 grams of water from 14.5 to 15.5 degrees C.
kinetochores Structures at the centromeres of the chromosomes to which the Şbers of the mitotic spindle connect.
kingdoms Five broad taxonomic categories (Monera, Protista, Plantae, Fungi, Animalia) into which organisms are grouped, based on common characteristics.
Klinefelter syndrome In humans, a genetically determined condition in which the individual has two X and one Y chromosome. Affected individuals are male and typically tall and infertile.
Kreb's cycle Biochemical cycle in cellular aerobic metabolism where acetyl CoA is combined with oxaloacetate to form citric acid; the resulting citric acid is converted into a number of other chemicals, eventually reforming oxaloacetate; NADH, some ATP, and FADH2 are produced and carbon dioxide is released.
