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C

CCR3
chemotactic chemokine receptor 3
CCR5
chemotactic chemokine receptor 5
C-terminal
[view]
C value
[discussion]
Cadherins
Caenorhabditis elegans
[genome][germline vs somatic cells]
Calciferol
[Discussion]
Calcitonin
[Discussion]
Calcitriol
The active form of vitamin D [1,25(OH)2D3]. [More]
Calcium
Metallic element (No. 20) that plays many essential roles in living processes.
[in nutrition][RDA] [homeostatic regulation of]
Calcium-calmodulin-dependent kinase II
CaMKII
Calorie
The amount of heat required to raise the temperature of 1 g of water 1 degree Celsius. When capitalized, a unit of heat 1000 times larger than the above.
Calvin cycle
[More][role of light reactions]
Cambium
Layer of meristematic cells in the roots and stems of many vascular plants that produces secondary xylem and phloem.
Cambrian period
CaMKII
Calcium-calmodulin-dependent kinase II
Cancer
Any disease characterized by an uncontrolled proliferation of one kind of cell. [General discussion] [Chronic Myelogenous Leukemia][Cancer Cells in Culture] [Burkitt's Lymphoma] [lung cancer] [colon cancer] [Oncogenes] [tumor suppressor genes] [and apoptosis] [caused by power lines?] [and telomeres]
Capillaries
[physiology]
Capping
[of pre-mRNA]
Carbonic anhydrase
Carbonyl group
Structure
Carbohydrate
Organic molecule containing carbon, hydrogen, and oxygen, generally with a 2:1 ratio of hydrogen atoms to oxygen atoms. Sugars, starches, and cellulose are carbohydrates. [Illustrated discussion]
Carbon dioxide
[transport by blood]
Carboxyl terminal
The end of a polypeptide chain with a free carboxyl (-COOH) group attached to the main chain. Synthesis of polypeptides proceeds from the amino terminal to the carboxyl terminal.[View]
Carboxypeptidase
Carcinogen
A substance that causes cancer.
Carcinoma
A cancer of epithelial cells.
Cardiac muscle
Heart muscle. [Discussion]
Carpel
Cartilage
Caspase
Proteolytic enzyme involved in apoptosis.
Catabolism
Destructive metabolism in which complex molecules are broken down into simpler ones, with the liberation of energy. [ More ]
Catabolite activator protein (CAP)
Catalase
Catalyst
Substance that accelerates the rate of chemical reaction without being used up in the process. Enzymes are catalysts.
Cataracts
Catecholamines.
Catenins
CCK
Cholecystokinin
CD4
subset of T cells   [in AIDS]
CD8
subset of T cells
CellCept
Cell Cycle
Discussion
Cell-mediated immunity
An immune response (e.g., graft rejection) that is dependent on specifically sensitized (i.e., able to recognize antigen) T lymphocytes. [More]
Cell plate
[in plant cytokinesis]
Cellular respiration
[Discussion]
Cellulose
Cenozoic era
Centimorgan (cM)
Central dogma
[Discussion]
Centriole
[Discussion]
Centromere
[of chromosome]
Centrosome
[General discussion] [in mitosis]
Cephalosporins
Cerebellum
Cerebrospinal fluid (CSF)
Cesium
A rare element that resembles potassium in its chemical properties. Nuclear reactors produce radioactive cesium-137. If this escapes into the environment (as it did at Chernobyl), it can enter human tissue masquerading as potassium.
Chaparral
The scrub forest biome found in Southern California.
Chaperone
A protein that stabilizes newly-synthesized, unfolded proteins until they reach their final destination where they can assume their characteristic three-dimensional shape.[protein folding] [in protein kinesis]
Character displacement
Evolutionary divergence of two species that reduces the amount of niche overlap between them.
Chargaff
[his rule]
Chemiosmosis
[in chloroplasts][in mitochondria]
Chemoautotrophic
Autotrophic, using energy secured by oxidizing some inorganic substance. Characteristic of certain bacteria.
Chemokine
A cytokine that attracts white blood cells (WBCs). These secreted proteins regulate the migration of WBCs from the blood into the tissues and promote inflammation. Some are also essential for proper embryonic development. Over 40 different chemokines have been identified. [Some examples]
Chemotherapy
Treating a patient with chemicals to combat an infectious disease or cancer.
Chernobyl
[radiation] [effect of fallout]
Chiasma
The attachment of two nonsister chromatids in a bivalent that is first seen in diplotene of prophase I of meiosis. Each chiasma results in the exchange of genes between the nonsister chromatids (i.e., crossing over). The plural is chiasmata.[More]
Chitin
Nitrogen-containing polysaccharide that forms the exoskeleton of arthropods and the cell walls of many fungi.
Chloracne
[from dioxin]
Chlorination
[of water supplies]
Chlorofluorohydrocarbons (CFCs)
[ozone layer]
Chlorophyll
Green pigment used in photosynthesis.
Chloroplasts
[genome]
Cholecystokinin
CCK
Cholera
[1991 epidemic]
Cholesterol
Steroid found in cell membranes and also used as the precursor for the synthesis of several steroid hormones (e.g., estrogens and glucocorticoids). [Discussion] [uptake by cells]
Cholinesterase
Enzyme that hydrolyzes and thus inactivates acetylcholine. Also called acetylcholinesterase. [At neuromuscular junction]
chordin (chd)
[role of gene in frog embryology]
Chorion
The outer extraembryonic membrane of reptiles, birds, and mammals. In mammals it contributes to the formation of the placenta. [More]
Choroid coat
of human eye
Chorionic gonadotropin
hCG
Chorionic villus sampling (CVS)
Medical procedure in which cells are removed from the chorion for testing.
Chromatid
Each of the two strands ("sister" chromatids) of a duplicated chromosome while they remain attached by their shared centromere. [Diagram]
Chromatin
The material (about 50% DNA and 50% proteins) of which chromosomes are made. [More]
Chromatography
The process of separating the components of a mixture by their differential adsorption to an insoluble matrix (e.g., paper) as the mixture is passed through the matrix. [affinity chromatography] [exclusion chromatography]
Chromosome
Molecule of DNA containing genes arranged in a linear order and associated with proteins and, often, some RNA. Chromosomes become sufficiently compact during mitosis and meiosis that they can be seen under the light microscope. The number of chromosomes is usually constant for each species. [More] [chromosome maps]
Chronic myelogenous leukemia (CML)
[Discussion][mutation]
Chymotrypsin
Cigarettes
[and health]
Cilia
Circadian
Occurring approximately once a day.
Citric acid cycle
[Discussion]
Cleavage
Repeated mitotic cell divisions of the zygote which forms the many-celled blastula, usually without any increase in overall size. [in frog] [discussion]
Clinical trials
of drugs
Cloaca
Posterior part of the alimentary canal into which the urinary and reproductive tracts empty in birds, reptiles, amphibians, and many fishes.
Clonal selection
in the immune system
Clone
The descendants produced asexually from a single cell or organism. Characterized by a identical genetic constitution.[cloning DNA] [cloning animals]
CMA-676
Cnidaria
The phylum of animals that includes the hydra, jellyfishes, sea anemones, and corals. Formerly called Coelenterata.
Cocaine
Codominance
The independent expression of each of two alleles in a heterozygote.
Codon
The 3 adjacent nucleotides in a molecule of DNA or messenger RNA that code for a particular amino acid (or, in three cases, stop translation).
[DNA codons] [RNA codons][mRNA translation]
Coelom
Main body cavity of many animals. It is lined with an epithelium derived from mesoderm.
Coenzyme
Organic molecule associated with certain enzymes and required for their activity. [More] Several vitamins are components of coenzymes.
Cohesion
Force of attraction between like molecules.
Coleoptile
Protective sheath surrounding the plumule of grass seedlings.
Collagen
Extracellular glycoprotein abundant in connective tissue. [More]
Collective dose
Discussion
Collenchyma
Supporting plant tissue consisting of living cells whose walls are thickened at the corners. Often found in young, growing stems and petioles. [View]
Colloid
Substance whose particles (macromolecules or aggregates of smaller molecules) range from 1-1000 nm in size.
Color blindness
Colostrum
Fluid synthesized by mammary glands shortly after birth and before milk production begins. Colostrum is rich in antibodies and provides passive immunity to the newborn.
Community
The population of plants, animals, and microbes found in a particular area and often interacting with one another.
Companion cell
Competitive inhibition
of enzymes
Complementary DNA (cDNA)
A DNA molecule synthesized (by reverse transcriptase) from an RNA template. When the template is messenger RNA (mRNA), the cDNA represents an intronless gene.
Compound
Substance that can be decomposed into simpler substances. The elements of a compound are present in definite proportions by weight. [More]
Computed tomography (CT)
Cones
of human retina
Conifer
A cone-bearing gymnosperm. Includes pines, spruces, and firs.
Conjugation
Form of sexual reproduction in which genes are exchanged during the temporary union of two cells. Occurs in many ciliates (e.g., Paramecium) and some bacteria.
Connective tissue
Connexins
Contact dermatitis
Delayed response to an allergen on the skin. [More] [still more]
Contraceptive, oral
Convergence
Evolution of superficially similar traits in unrelated organisms that lived in a similar environment.
Copulation
Physical union of two animals during which sperm cells are transferred from one to the other.
Corpus luteum
Corepressor
A small molecule that joins with a repressor protein to block gene transcription in prokaryotes. [tryptophan as a corepressor]
Cornea
of human eye
Coronary system
Cortex
The outer part of an organ.
Corticotropin-releasing hormone
CRH
Cortisol
Cotyledon
Covalent bond
Chemical bond formed by one or more shared pairs of electrons. [More]
CpG islands
Tracts of alternating cytosines (C) and guanines (G) in DNA. The Cs in CpG islands are often methylated. [role in genomic imprinting]
Cranial nerves
Creatine phosphate
[role in contraction of skeletal muscle]
Cristae
[in mitochondria]
Crossing over
[in meiosis]
Cushing's syndrome
Cyanobacteria
A group of photosynthetic prokaryotes formerly known as blue-green algae.
Cyclic ADP ribose
Cyclic AMP
cAMP
Cyclin
One of several proteins that must sequentially and temporarily associate with cyclin-dependent kinases (CDKs) in order for the cell to pass to the next stage of the cell cycle. [Discussion]
Cyclosporine
An immunosuppressant.
Cysteine
[structure]
Cystic fibrosis (CF)
[mutations]
Cytochrome
One of several iron-containing proteins, found in mitochondria and chloroplasts, that transfer electrons in the process of cellular respiration and photosynthesis, respectively. [in mitochondria] [in chloroplasts]
Cytokine
Protein secreted by a cell that signals other cells in a paracrine fashion or even itself (autocrine). The various lymphokines, chemokines, interferons, colony-stimulating factors, and tumor necrosis factor are examples.
Cytokinesis
The division of the cytoplasm - as contrasted with the nucleus - during mitosis or meiosis.[More]
Cytokinins
Plant hormones.
Cytoplasm
General term for all the contents of the cell outside the nucleus and within the plasma membrane.
Cytosine
[structure]
Cytosol
The fluid in which the organelles of the cytoplasm are suspended. Also called the ground substance of the cell.
Cytotoxic T lymphocyte (CTL)
[More]
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