Lewis/Life - Glossary

C

C3 plant Plant that uses the Calvin cycle only to fix carbon dioxide. 159

C4 photosynthesis see-4 foto-SIN-the-sis In plants, a biochemical pathway that prevents photorespiration. 160

calcitonin KAL-sah-TOE-nin A thyroid hormone that decreases blood calcium levels. 669

calyx KA-liks One of two outermost whorls of a flower. 563

canaliculi can-al-IK-u-li Passageways in bone that connect lacunae. 595

capacitation cah-PASS-eh-TAY-shun Activation of sperm cells in the human female reproductive tract. 217

carbohydrase KAR-bo-HI-drase Enzyme that breaks down certain disaccharides into monosaccharides. 762

carbohydrate CAR-bo-HI-drate Compound containing carbon, hydrogen, and oxygen, with twice as many hydrogens as oxygens; sugar or starch. 43

carboxyl group kar-BOX-ill GROOP A carbon atom double-bonded to an oxygen and single-bonded to a hydroxyl group (OH). 47

cardiac cycle The sequence of contraction and relaxation that makes up the heartbeat. 720

cardiac muscle cell Striated, involuntary, single-nucleated contractile cell in the mammalian heart. 598

cardiac output The volume of blood the heart ejects in 1 minute. 727

carotenoids kare-OT-in-oydz Yellow and orange plant pigments. 150, 587

carotid rete care-OT-id REE-tee A configuration of blood vessels in the brain that cools the brain. 770

carpel KAR-pel Leaflike structure in a flower that encloses ovules. 563

carrying capacity The theoretical maximum number of individuals an environment can support. 842

cartilage CAR-teh-lij A supportive connective tissue consisting of chondrocytes embedded in collagen and proteoglycans. 594

Casparian strip kas-PAHR-ee-an STRIP A single layer of tightly packed cells that forms the endodermis of a plant. 548

catabolism cah-TAB-o-liz-um Metabolic degradation reactions, which release energy. 114

catalysis kat-AL-i-sis Speeding a chemical reaction. 49

catecholamines kat-ah-KOLE-ah-meens Hormones of the adrenal medulla. 670

cell The structural and functional unit of life. 5, 60

cell body The enlarged portion of a neuron containing most of the organelles. 596, 611

cell cycle The life of a cell, in terms of whether it is dividing or in interphase. 168

cell membrane Proteins embedded in a lipid bilayer, which forms the boundary of cells. 66

cell population A group of cells with characteristic proportions in particular stages of the cell cycle. 179

cell theory The ideas that all living matter consists of cells, cells are the structural and functional units of life, and all cells come from preexisting cells. 61

cellular adhesion molecule SEL-u-ler ad-HEE-jhun MOL-e-kuel (CAM) A protein that enables cells to interact with each other. 85

cellular immune response The actions of T and B cells in the immune system. 797

cellular respiration Biochemical reactions that extract energy in mitochondria. 114, 126

cell wall A rigid boundary consisting of peptidoglycans in prokaryotic cells and cellulose in plant cells. 14, 64

central nervous system (CNS) The brain and the spinal cord. 611

centrioles SEN-tre-olz Paired, oblong structures consisting of microtubules in animal cells that organize the mitotic spindle. 74, 171

centromere SEN-tro-mere A characteristically located constriction in a chromosome. 171, 296

centrosome SEN-tro-soam A region near the cell nucleus that contains the centrioles. 171

cephalized CEF-a-lized An animal body form with a head end. 512

cerebellum ser-eh-BELL-um An area of the brain that coordinates muscular responses. 625

cerebrospinal fluid sah-ree-bro-SPI-nal FLU-id Fluid similar to blood plasma that bathes and cushions the central nervous system. 635

cerebrum seh-REE-brum The higher region of the brain that controls intelligence, learning, perception, and emotion. 625

cervix SER-viks In the female human, the opening to the uterus. 197

chaperone protein shap-ER-one PRO-teen A protein that stabilizes a growing amino acid chain. 336

chemical bond Attachments atoms form by sharing or exchanging electrons. 35

chemical equilibrium KEM-e-cal e-kwil-IB-ree-um When a chemical reaction proceeds in both directions at the same rate. 116

chemical reaction Interactions in which atoms exchange or share electrons, forming new chemicals. 35

chemiosmosis KEM-ee-oss-MOE-sis Phosphorylation of ADP to ATP occurring when protons that are following a concentration gradient contact ATP synthase. 135

chemoautotroph KEEM-o-awt-o-trofe An organism that derives energy from chemicals in nonliving surroundings. 112

chemoreception KEEM-o-ree-SEP-shun Smell and taste. 644

chemotroph KEEM-o-trofe An organism that obtains energy by oxidizing chemicals. 445

chlorenchyma klor-REN-kah-mah Chloroplast-containing parenchyma cells. 536

chlorophyll a KLOR-eh-fill A A green pigment plants use to harness the energy in sunlight. 75, 149

chloroplast KLOR-o-plast A plant cell organelle housing the reactions of photosynthesis. 74, 151

choanocytes cho-AN-o-sites Collar cells in sponges that produce a current that draws food and water into the central cavity. 515

chondrocyte KON-dro-site A cartilage cell. 595

chordate KOR-dayt Animal with a notochord, hollow nerve cord, and gill slits. 513

chorion KOR-ee-on A membrane that develops into the placenta. 218

chorionic villi KOR-ee-ON-ik VIL-i Fingerlike projections extending from the chorion to the uterine lining. 223

chromatid KRO-mah-tid A continuous strand of DNA comprising an unreplicated chromosome or one-half of a replicated chromosome. 171

chromosome KRO-mo-soam A dark-staining, rod-shaped structure in the nucleus of a eukaryotic cell consisting of a continuous molecule of DNA wrapped in protein. 168, 285

chyme KIME Semisolid food in the stomach. 760

chymotrypsin KI-mo-TRIP-sin A pancreatic enzyme that digests protein in the small intestine. 762

chytrid KI-trid Unicellular eukaryote with single flagella and chitinous cell walls. 458

cilia SIL-ee-ah Protein projections from cells that beat coordinately, moving cells and substances. 99

ciliary body SIL-ee-air-ee BOD-ee A highly folded, specialized structure in the center of the choroid coat of the human eye that houses the ciliary muscle, which alters the shape of the lens. 648

circadian rhythm sir-KA-dee-en RITH-um Regular, daily rhythm of a biological function. 587

classical conditioning A form of learning in which an animal responds in a familiar way to a new stimulus. 815

cleavage KLEEV-ij A period of rapid cell division following fertilization but before embryogenesis. 218

cleavage furrow KLEEV-ij FUR-o The initial indentation between two progeny cells in mitosis. 173

climax community The species in a community that persist when the environment doesn't change. 856

clitellum cli-TELL-um Part of the outside of earthworms that secretes mucus during copulation and a cocoon early in development. 521

clitoris CLIT-or-is A small, highly innervated bit of tissue at the juncture of the labia that is the female anatomical equivalent of the penis. 198

closed circulatory system A circulatory system that contains blood in vessels. 708

club mosses A type of seedless vascular plant. 497

cluster-of-differentiation (CD4) antigen CLUSS-ter uv diff-er-en-she-AY-shun AN-teh-jen A protein on a helper T cell that recognizes a nonself antigen on a macrophage, initiating an immune response. 797

Cnidaria SNID-air-ee-a An animal phylum whose members have a hollow two-layered body, with a jellylike interior and radial symmetry. 510, 516

cnidocytes SNID-o-sites Structures in cnidaria that contain stinging cells. 516

cocci KOK-si Round bacteria. 443

cochlea COKE-lee-ah The spiral-shaped, hindmost part of the inner ear, where vibrations are translated into nerve impulses. 653

codominant ko-DOM-eh-nent Alleles that are both expressed in the heterozygote. 273

codon KO-don A continuous triplet of mRNA bases that specifies a particular amino acid. 329

coefficient of relationship co-eff-FISH-ent uv re-LAY-shun-ship A measurement of how closely related two individuals are, based upon the proportion of genes they share. 278

coelom SEE-loam A central body cavity in an animal. 511

coenocytic seen-o-SIT-ik Fungal hyphae in which protoplasm streams continuously 477.

coenzyme coe-EN-zime An organic cofactor necessary for the function of certain enzymes. 119

coevolution ko-ev-eh-LU-shun The interdependence of two types of organisms for survival. 374

cofactor COE-fac-tor A biochemical necessary for an enzyme to function. 119

cohesion co-HEE-jhun The strong attraction of water molecules to each other. 40

coleoptile KOL-ee-OP-tile A sheathlike structure that covers the plumule in monocots. 568

collagen COLL-a-jen A connective tissue protein. 594

collecting duct A structure in the kidney into which nephrons drain urine. 783

collenchyma kol-LEN-kah-mah Elongated, living cells that differentiate from parenchyma and support growing regions of shoots. 536

colon Kol-en The large intestine. 763

colony-stimulating factors Secreted growth factors that stimulate blood cells to specialize. 717

columnar col-UM-nar Tall cells, as in epithelium. 594

commensalism co-MEN-sal-izm A symbiotic relationship in which one member benefits without affecting the other member. 434

compact bone A layer of solid, hard bone that covers spongy bone. 689

companion cells Cells that transfer carbohydrates to and from sieve tube members. 539

complementary base pairs Bonding of adenine to thymine and guanine to cytosine in the DNA double helix. 313

complement system A group of proteins that assist other immune defenses. 791

complex trait A trait caused by genes and the environment. 276

compound A molecule including different atoms. 34

concentration gradient Passive diffusion of ions from an area of high to low concentration. 88

concordance kon-KOR-dance A measure of the inherited component of a trait. The number of pairs of either monozygotic or dizygotic twins in which both members express a trait, divided by the number of pairs in which at least one twin expresses the trait. 279

conditioned stimulus A new stimulus coupled to a familiar or unconditioned stimulus, so that an animal associates the two. 815

cones Specialized receptor cells in the center of the retina that detect colors. 560, 648

conformation KON-for-MAY-shun The three-dimensional shape of a protein. 49

conifers CON-i-ferz One of four divisions of gymnosperms; tall, ancient trees. 498

conjugation con-ju-GAY-shun A form of gene transfer in bacteria. 000 A form of sexual reproduction in protozoa. 194, 449, 459

connective tissue Tissue consisting of cells embedded or suspended in a matrix, including loose and fibrous connective tissues, cartilage, bone, and blood. 594

constant regions The sequence of amino acids in the lower parts of heavy and light antibody chains, which vary in different antibody types. 795

contest competition When members of a population compete for a resource indirectly. 843

contractile vacuole KON-tract-till VAK-u-ol An organelle in a paramecium that pumps water out of the cell. 90, 459

convergent evolution kon-ver-gent ev-o-LU-shun Organisms that have similar adaptations to a similar environmental challenge but that are not related by descent. 379

cork cambium KORK KAM-bee-um The lateral meristem that produces the periderm, the covering on mature stems and roots. 550

cork cells Waxy cells on mature stems and roots. 552

cornea KOR-nee-ah A modified portion of the human eye's sclera that forms a transparent curved window that admits light. 648

corolla kah-ROLE-ah One of two outermost whorls of a flower, with no direct role in sexual reproduction. 563

corona radiata kah-RONE-ah ray-dee-A-tah Layer of cells around the oocyte. 217

corpus luteum KOR-pis LU-te-um A gland formed from an ovarian follicle that has recently released an oocyte; produces estrogen and progesterone. 674

cortex KOR-teks In plants, the ground tissue in between the epidermis and vascular tissue in stems. 541

cotyledons KOT-ah-LEE-donz Embryonic leaves in flowering plants that store energy for germination. 544

countercurrent exchange system Passage of heat from one blood vessel to another. 770

countercurrent flow Fluid flow in different parts of a continuous tubule in opposite directions, which maximizes the amount of a particular substance that diffuses out of the tubule. 734

coupled reactions CUP-uld re-AC-shuns Two chemical reactions that occur simultaneously and have a common intermediate. 119

covalent bond KO-va-lent BOND Atoms sharing electrons. 35

creatine phosphate KRE-ah-tin FOS-fate A molecule stored in muscle fibers that can donate its high-energy phosphate to ADP to regenerate ATP. 697

cristae KRIS-ty The folds of the inner mitochondrial membrane along which many of the reactions of cellular respiration occur. 71, 128

critical period The time during prenatal development when a structure is vulnerable to damage. 246

crop Food-storing structure in birds. 754

crossing-over Exchange of genetic material between homologous chromosomes during prophase of meiosis I. 200

cuticle KEW-tah-kal A tissue covering all of a plant except the roots. 536

cutin KEW-tin A fatty material that a plant's epidermal cells produce that forms a cuticle. 536

cyanobacteria si-an-o-bak-TEAR-ee-ah Unicellular algae that have bluish-green pigments. 64

cycads SI-kadz One of four divisions of gymnosperms; tall, ancient trees. 498

cyclic adenosine monophosphate SI-klik a-DEN-o-seen mon-o-FOS-fate (cAMP) A second messenger. 661

cyclin SI-klin A type of protein that controls the cell cycle. 177

cyst SIST A dormant form of a protozoan that has a cell wall and lowered metabolism. 459

cytochrome SI-to-krome An iron-containing molecule that transfers electrons in metabolic pathways. 121

cytogenetics si-to-jen-ET-ix Correlation of an inherited trait to a chromosomal anomaly. 286

cytokines SI-toe-kines Chemicals that B cells secrete. 791

cytokinesis SI-toe-kin-E-sis Distribution of cytoplasm, organelles, and macromolecules into two progeny cells in cell division. 168

cytokinins SI-toe-KI-ninz A class of plant hormones that promote division of the cell following nuclear divisions in seeds, roots, young leaves, and fruits. 577

cytoplasm SI-toe-PLAZ-um The jellylike fluid in which organelles are suspended in eukaryotic cells. 61

cytosine SI-toe-seen One of the two pyrimidine nitrogenous bases in DNA and RNA. 51

cytoskeleton SI-toe-SKEL-eh-ten A framework of arrays of protein rods and tubules in animal cells. 67

cytotoxic T cell si-toe-tocks-ik T SEL Immune system cell that kills nonself cells by binding them and releasing chemicals. 797

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