Lewis/Life - Glossary

L

labor Uterine contractions that expel a fetus. 216

lacteal LAK-tee-ul A lymph vessel that absorbs fat in the small intestine. 762

lactic acid fermentation LAK-tik AS-id fer-men-tay-shun Conversion of pyruvic acid into lactic acid, occurring in some anaerobic bacteria and tired mammalian muscle cells. 139

lacunae la-KEW-nay Spaces in cartilage and bone tissue. 595

laminin LAM-i-nin A protein that binds skin layers. 102, 599

lancelets LAN-si-letz One of the three groups of chordates, including primitive invertebrates. 525

larynx LAR-inks The "voice box" and a conduit for air. 736

latent learning LA-tent LERN-ing Learning without reward or punishment; not apparent until after the learning experience. 816

lateral meristems LAT-er-al MER-ee-stemz Actively dividing plant cells that grow outward, thickening the plant. 534

law of segregation Allele separation during meiosis. 263

leader sequence A short sequence at the start of each mRNA that enables the mRNA to hydrogen bond with part of the rRNA in a ribosome. 332

leaf abscission LEAF ab-SCISZ-on Shedding of a tree's leaves as part of its life cycle. 546

lens The structure in the eye through which light passes and is focused. 648

lentic system Len-tik SIS-tum Freshwater biome that has standing water, such as a lake or pond. 879

life expectancy Prediction of how long an individual will live, based on current age and epidemiology. 234

life span The longest a member of a species can live. 234

ligaments LIG-ah-mentz Tough bands of fibrous connective tissue that form a joint capsule. 700

ligand LIG-and A messenger molecule that binds to a cell surface protein. 94

ligase LIG-aze An enzyme that catalyzes formation of covalent bonds in the DNA sugar-phosphate backbone. 317

light chains The two smaller polypeptide chains in an antibody subunit. 795

lignin LIG-nin A carbohydrate in plants that adds support. 493

limnetic zone lim-NET-ik ZONE The layer of open water in a lake or pond that light penetrates. 879

linkage map LINK-ege map Diagram of gene order on a chromosome based on crossover frequencies. 288

linked genes Genes on the same chromosome. 286

lipase LI-payse Enzyme that chemically digests fats. 762

lipids LIP-idz Compounds containing carbon, hydrogen, and oxygen, but with less oxygen than carbohydrates. 44

lithotroph LITH-o-trofe Organism that obtains electrons from reduced inorganic compounds. 445

littoral zone Lit-or-al ZONE The shallow region along the shore of a lake or pond where sufficient light reaches to the bottom for photosynthesis. 879

liver The largest solid organ in the body. It detoxifies blood, stores glycogen and fat-soluble vitamins, synthesizes blood proteins, and monitors blood glucose level. 757

liverwort LIV-er-wart A type of bryophyte. 493

long-day plant Plant that requires light periods longer than some critical length to flower. 584

loose connective tissue Connective tissue with widely spaced fibroblasts and a few fat cells. 594

lotic system LO-tik SIS-tum Freshwater biome with running water, such as a river or stream. 879

low-density lipoprotein LO DEN-sit-ee LIP-o-PRO-teen A molecule that carries cholesterol. 94

lungs Paired structures that house the bronchial tree and the alveoli; the sites of gas exchange. 735, 739

luteinizing hormone LU-ten-I-zing HOR-moan (LH) A hormone made in the anterior pituitary that promotes ovulation. 666

lymph LIMF Blood plasma minus some large proteins, which flows through lymph capillaries and lymph vessels. 727

lymphatic system lim-FAH-tik SIS-tum A circulatory system that consists of lymph capillaries and lymph vessels that transport lymph. 727

lymph capillaries LIMF CAP-eh-lair-eez Dead-end, microscopic vessels that transport lymph. 727

lymph nodes LIMF NODES Structures in the lymphatic system that contain white blood cells and fight infection. 728

lymph vessels LIMF VES-selz Vessels that transport lymph and eventually empty into veins. 727

lysosome LI-so-soam A sac in a eukaryotic cell in which molecules and worn-out organelles are enzymatically dismantled. 71

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