BIO - TERMS - FREQUENCY > 1 PT 7

Question 1

absolute refractory period

Answer 1

Time period when an excitable cell cannot be restimulated to respond. // The period of time, measured from the onset of an action potential, during which another action potential cannot be triggered.

Question 2

adaptive immunity

Answer 2

Immunity to infection conferred by an adaptive immune response. // The ability, obtained during the life of the individual, to produce specific antibodies and T cells.

Question 3

affinity maturation

Answer 3

Progressive increase in the affinity of antibodies for the immunizing antigen with the passage of time after immunization. // The increase in affinity for their specific antigen of the antibodies produced as an adaptive immune response progresses. This phenomenon is particularly prominent in secondary and subsequent immunizations.

Question 4

allograft

Answer 4

A tissue graft that is not from a genetically identical donor (i.e., not from self or an identical twin). // A transplant of tissue from an allogeneic (genetically nonidentical) donor of the same species. Such grafts are invariably rejected unless the recipient is immunosuppressed.

Question 5

amphibolic pathway

Answer 5

A pathway that is both anabolic and catabolic. // A metabolic pathway used in both catabolism and anabolism.

Question 6

angiotensin-converting enzyme (ACE)

Answer 6

An enzyme of angiotensin synthesis; important drug target. // An enzyme in the lung that converts angiotensin I to angiotensin II.

Question 7

antiserum

Answer 7

A blood-derived fluid containing antibodies. // The fluid component of clotted blood from an immune individual that contains antibodies against the antigen used for immunization. An antiserum contains a mixture of different antibodies that all bind the antigen, but which each have a different structure, their own epitope on the antigen, and their own set of cross-reactions. This heterogeneity makes each antiserum unique.

Question 8

ascospore

Answer 8

A sexual fungal spore produced in an ascus, formed by the ascomycetes. // One of the spores contained in the ascus of certain fungi such as Neurospora.

Question 9

Aufbau principle

Answer 9

The rules for determining the electron coniguration of an atom. // The principle that indicates the pattern of orbital filling in an atom.

Question 10

Avoidance

Answer 10

The capability of a plant to resist stress by minimizing the impacts encountered by the plant. // Mechanisms that prevent a host’s exposure to microbes, such as anatomic barriers or particular behaviors.

Question 11

beta (β) particle

Answer 11

A medium-energy particle released during beta decay; equivalent to an electron.

Question 12

Blastula

Answer 12

In animals, an early embryo form that follows the morula stage; typically, a single-layered sheet or ball of cells. // Early stage of an animal embryo, usually consisting of a hollow ball of epithelial cells surrounding a fluid-filled cavity, before gastrulation begins.

Question 13

C-reactive protein

Answer 13

The most sensitive acute-phase reactant. // An acute-phase protein that binds to phosphocholine, a constituent of the surface C-polysaccharide of the bacterium Streptococcus pneumoniae and of many other bacteria, thus opsonizing them for uptake by phagocytes.

Question 14

carbon-fixation reaction

Answer 14

Process by which inorganic carbon (as atmospheric CO2) is incorporated into organic molecules. The second stage of photosynthesis. // The reactions, catalyzed by rubisco during photosynthesis or by other carboxylases, in which atmospheric CO2 is initially incorporated (fixed) into an organic compound.

Question 15

cDNA (complementary DNA)

Answer 15

DNA made in vitro from an mRNA template. // A DNA molecule synthesized in vitro from an RNA template.

Question 16

chemical energy

Answer 16

Energy stored in the chemical bonds of a molecule. // The energy associated with the relative positions of electrons and nuclei in atoms and molecules.

Question 17

Chirality center (chiral center)

Answer 17

An atom (usually carbon) that is bonded to four different groups. // An atom with substituents arranged so that the molecule is not superposable on its mirror image.

Question 18

class

Answer 18

A taxonomic group between phylum and order.

Question 19

Collagen

Answer 19

A family of fibrous proteins in the extracellular matrix, with a characteristic triple-helical structure. // Fibrous protein rich in glycine and proline that is a major component of the extracellular matrix in animals, conferring tensile strength. Exists in many forms: type I, the most common, is found in skin, tendon, and bone; type II is found in cartilage; type IV is present in basal laminae.

Question 20

condensation

Answer 20

The phase transition from gas to liquid. // A reaction type in which two compounds are joined with the elimination of water.

Question 21

Constitutive enzyme

Answer 21

An enzyme that is synthesized continually regardless of growth conditions (cf. Inducible enzyme and Repressible enzyme). // Enzymes required at all times by a cell and present at some constant level; for example, many enzymes of the central metabolic pathways. Sometimes called housekeeping enzymes.

Question 22

creatine

Answer 22

(krē′-ă-tēn; -tin) Chemical providing muscle cells with energy; present as creatine phosphate. // A metabolite in muscle that forms the energy-rich compound creatine phosphate.

Question 23

death receptor

Answer 23

Receptors for extracellular ligands; their activation triggers apoptosis. // Transmembrane receptor protein that can signal the cell to undergo apoptosis when it binds its extracellular ligand.

Question 24

desensitization

Answer 24

The prevention of allergic inflammatory responses. // Universal process by which sensory mechanisms cease to respond after prolonged exposure to the specific stimulus they detect.

Question 25

dimer

Answer 25

The product that forms from the reaction of two monomers. // A compound having the same percentage composition as another but twice the molecular weight; one formed by polymerization.

Question 26

DNA fingerprinting

Answer 26

DNA-based methods for the identification of persons in criminal cases. // Analysis of DNA by electrophoresis of restriction enzyme fragments of the DNA.

Question 27

dorsal

Answer 27

An anatomical reference meaning toward the back. // (dōr′săl) Toward the back. dorsiflexion (dōr-si-flek′shŭn) Movement of the foot whereby the dorsum of the foot is brought closer to the anterior leg region.

Question 28

effector memory T cells (TEM)

Answer 28

Memory T cells that produce cytokines rapidly upon re-encountering a viral antigen, and are generally present in the circulatory system. (Chapter 4) // Memory lymphocytes that recirculate between blood and peripheral tissues and are specialized for rapid maturation into effector T cells after restimulation with antigen in nonlymphoid tissues.

Question 29

electron shell

Answer 29

A group of an atom’s electrons with the same principal quantum number. // A region of an atom where electrons orbit the nucleus, corresponding to an energy level.

Question 30

endorphin

Answer 30

Peptides that activate opiate receptors. // One of many endogenous opioid peptides with actions similar to those of morphine; present in many brain structures, particularly those related to pain.

Question 31

epidemiology

Answer 31

The science that studies when and where diseases occur and how they are transmitted. // Th e study of the incidence, distribution, and spread of infectious disease in populations with particular regard to identifi - cation and subsequent control. (Chapter 1)

Question 32

Exonuclease

Answer 32

An enzyme that digests DNA or RNA, beginning at the ends of strands. // Enzymes that hydrolyze only those phosphodiester bonds that are in the terminal positions of a nucleic acid.

Question 33

fatty liver

Answer 33

Fat infiltration and inflammation of the liver. // A reversible lesion caused by increased hepatic triglyceride synthesis or impaired very-lowdensity lipoprotein (VLDL) formation.

Question 34

Fitness

Answer 34

Th e degree to which an organism is able to reproduce its environment. (Chapter 10) // The number of offspring left by an individual, often compared with the average of the population or with some other standard, such as the number left by a particular genotype.

Question 35

fomite

Answer 35

A nonliving object that can spread infection. // Inanimate objects that may be contaminated with microorganisms and become vehicles for transmission. (Chapter 1)

Question 36

Gametogenesis

Answer 36

The formation of gametes. // (gam′ĕ-tō-jen′ĕ- sis) Formation and development of gametes (sex cells).

Question 37

gene family

Answer 37

Structurally related genes with a common evolutionary origin. // The set of genes in an organism related in DNA sequence due to their derivation from the same ancestor. gene segments In immunology: short DNA sequences that are joined together during B cell and T cell development to produce the coding sequences for immunoglobulins and T cell receptors, respectively.

Question 38

glucose transporter (GLUT)

Answer 38

A family of proteins that transport glucose across cell membranes. // Designation for a family of membrane proteins that transport glucose.

Question 39

goiter

Answer 39

Hypertrophy of the thyroid gland, caused by a deficiency of iodine. // Enlargement of the thyroid gland; seen in some forms of hypothyroidism and hyperthyroidism.

Question 40

Graves disease

Answer 40

An autoimmune disease leading to hyperthyroidism. // An autoimmune disease in which antibodies against the thyroid-stimulating hormone receptor cause overproduction of thyroid hormone and thus hyperthyroidism.

Question 41

Hashimoto disease // Hashimoto’s thyroiditis

Answer 41

Autoimmune thyroiditis, the most common cause of hypothyroidism. // An autoimmune disease characterized by persistent high levels of antibody against thyroid-specific antigens. These antibodies recruit NK cells to the thyroid, leading to damage and inflammation.

Question 42

hepatitis

Answer 42

Inflammation of the liver.

Question 43

homotropic

Answer 43

Describes an allosteric modulator that is identical to the normal ligand. // Hydrogens in a molecule that give the identical structure on replacement by X and thus show identical NMR absorptions.

Question 44

Hydrophobic

Answer 44

Water-fearing; repelled by water. // Nonpolar; describes molecules or groups that are insoluble in water. // Substance that does not dissolve in water.

Question 45

hypoglycemia

Answer 45

Blood glucose concentration that is below fasting level. // Too little blood glucose, resulting in brain dysfunction.

Question 46

immunoglobulin domain (Ig domain)

Answer 46

Protein domain first described in antibody molecules but present in many proteins. // Characteristic protein domain of about 100 amino acids that is found in immunoglobulin light and heavy chains. Similar domains, known as immunoglobulin-like (Ig-like) domains, are present in many other proteins, which, together with Igs, constitute the Ig superfamily.

Question 47

inclusion

Answer 47

A temporary store of molecules in the cytosol. // Material held inside a cell, often consisting of reserve deposits.

Question 48

inhibitory G protein (Gi)

Answer 48

Trimeric G protein that can regulate ion channels and inhibit the enzyme adenylyl cyclase in the plasma membrane. See also G protein. // A trimeric GTP-binding protein that, when activated by an associated plasma membrane receptor, inhibits a neighboring membrane enzyme such as adenylyl cyclase. Compare stimulatory G protein (Gs).

Question 49

Integral membrane protein

Answer 49

Proteins that are embedded in the lipid bilayer. // Proteins that are embedded in a lipid bilayer, with external and internal domains connected by one or more membrane-spanning domains. (Chapters 2 and 4)

Question 50

Isomerase

Answer 50

Enzyme that interconverts isomers. // Enzymes that catalyze the transformation of compounds into their positional isomers.

Question 51

kinetic energy

Answer 51

The energy associated with motion of an object. // Energy of movement. Compare to potential energy.

Question 52

LD50

Answer 52

The lethal dose for 50% of the inoculated hosts within a given period. // The amount of a substance per kilogram body weight that is lethal to 50% of test animals.

Question 53

Lewis base

Answer 53

An atom, ion, or molecule that is an electron pair donor. // A substance that donates an electron lone pair to an acid. All nucleophiles are Lewis bases.

Question 54

lipoxygenase

Answer 54

An enzyme that is involved in the metabolism of longer-chain fatty acids into powerful biochemicals. // Enzymes that produce leukotrienes and other biologically active products from polyunsaturated fatty acids.

Question 55

Lysyl oxidase

Answer 55

An enzyme that produces allysyl residues in collagen; required for cross-linking. // A copper-containing enzyme that promotes the cross-linking of collagen and elastin fibrils by promoting the production of aldehydes and lysine residues that form bonds in these tissues.

Question 56

metabolite

Answer 56

A chemical intermediate in the enzyme-catalyzed reactions of metabolism. // Intermediates or end products of physiological processes, usually small molecules with molecular weights below 1 kDa.

Question 57

MHC restriction

Answer 57

Th e recognition of an antigen by T cells only when it is presented by MHC of the haplotype identical to that of the T cells. (Chapter 4) // The fact that a peptide antigen can only be recognized by a given T cell if it is bound to a particular self MHC molecule. MHC restriction is a consequence of events that occur during T-cell development.

Question 58

molality (m)

Answer 58

A means of expressing solution concentration as the number of moles of solute per kilogram of solvent.

Question 59

motor cortex

Answer 59

Cortical areas 4 and 6, which are directly involved in the control of voluntary movement. // Region of the brain that initiates voluntary skeletal muscle contraction.

Question 60

mycorrhiza

Answer 60

A fungus growing in symbiosis with plant roots. // Nutritional symbiosis between fungi and the root tips of plants.

Question 61

nerve

Answer 61

A bundle of axons within the peripheral nervous system.

Question 62

neutralizing antibodies

Answer 62

Antibodies that inhibit the infectivity of a virus or the toxicity of a toxin. // Antibodies that block the infectivity of virus particles. (Chapter 7)

Question 63

Nonessential amino acid

Answer 63

One of the eleven amino acids that are biosynthesized by humans. // Amino acids that can be made by humans and other vertebrates from simpler precursors and are thus not required in the diet.

Question 64

Nucleophile

Answer 64

An electron-rich species that donates an electron pair to an electrophile in a polar bond-forming reaction. Nucleophiles are also Lewis bases. // An electron-rich group with a strong tendency to donate electrons to an electron-deficient nucleus (electrophile); the entering reactant in a bimolecular substitution reaction.

Question 65

opsin

Answer 65

The protein portion of the visual pigment, which becomes rhodopsin with the addition of the chromophore retinal. // Lightsensitive protein of the photoreceptor cells in the retina of the eye. Opsins convert light in the form of photons into an electrochemical signal.

Question 66

Orotic acid

Answer 66

An intermediate of pyrimidine biosynthesis. //Normal metabolic intermediate of pyrimidine biosynthesis with hypocholesterolemic activity

Question 67

papilla

Answer 67

(pă-pil′ă; pl., papillae, -pil′ē) Small, nipplelike process. // A small protuberance on the surface of the tongue that contains taste buds.

Question 68

pathogenesis

Answer 68

The manner in which a disease develops. // The origin or cause of the pathology of a disease.

Question 69

peripheral membrane proteins // peripheral proteins

Answer 69

Proteins that are attached to the surface of the membrane. // Proteins loosely or reversibly bound to a membrane by hydrogen bonds or electrostatic forces; generally water soluble once released from the membrane. Compare integral proteins.

Question 70

phosphine

Answer 70

PH3; a colorless, poisonous gas that smells like decaying fish and has an oxidation state of -3 for phosphorus. // A trivalent phosphorus compound, R3P.

Question 71

phototroph

Answer 71

An organism that uses light at its primary energy source. // An organism that can use the energy of light to synthesize its own fuels from simple molecules such as carbon dioxide, oxygen, and water; as distinct from a chemotroph.

Question 72

plasmalogen

Answer 72

A phospholipid with an alkenyl ether substituent on C-1 of glycerol. // Phosphoglycerides containing an α,β-unsaturated fatty alcohol.

Question 73

polymorphic

Answer 73

Describes a protein for which amino acid sequence variants exist in a population of organisms, but the variations do not destroy the protein’s function. // Existing in a variety of different forms; applied to a gene, occurring in a variety of different alleles.

Question 74

porphyrin

Answer 74

Complex nitrogenous compound containing four substituted pyrroles covalently joined into a ring; often complexed with a central metal atom. // A type of pigment containing four pyrrole rings.

Question 75

priming

Answer 75

(1) In protein phosphorylation, the phosphorylation of an amino acid residue that becomes the binding site and point of reference for phosphorylation of other residues in the same protein. (2) In DNA replication, the synthesis of a short oligonucleotide to which DNA polymerases can add additional nucleotides. // The first encounter with a given antigen, which generates the primary adaptive immune response.

Question 76

pupil

Answer 76

(pū′pl) Circular hole in the center of the iris of the eye. // The opening that allows light to enter the eye and strike the retina.

Question 77

radioactivity

Answer 77

Emission of high energy radiation from a radioisotope. // The emission of subatomic particles or high-energy electromagnetic radiation by the unstable nuclei of certain atoms.

Question 78

recombinational DNA repair // recombinational repair

Answer 78

Recombinational processes directed at the repair of DNA strand breaks or cross-links, especially at inactivated replication forks. // Repair of DNA double-strand breaks guided by the homologous DNA sequence.

Question 79

renal // renal system

Answer 79

(rē′năl) Relating to the kidney. // The organs that are involved in the production of urine.

Question 80

resistance (R) factor

Answer 80

A bacterial plasmid carrying genes that determine resistance to antibiotics. // A plasmid that confers antibiotic resistance to a bacterium.

Question 81

Retrotransposon

Answer 81

A transposable element that creates new copies by reverse transcription of RNA into DNA. // Specific class of transposons that are able to amplify via RNA-intermediates, reintegrate, and may rapidly increase the genome size of an organism.

Question 82

saltatory conduction

Answer 82

The propagation of an action potential down a myelinated axon. // Transmission of an action potential along the plasma membrane of a myelinated axon.

Question 83

SCID (severe combined immunodeficiency syndrome)

Answer 83

Mutation in mice that causes severe combined immunodeficiency. It was eventually found to be due to mutation of the DNA repair protein DNA-PK. // A group of diseases characterized by the inability to mount an immune response, either humoral or cellular.

Question 84

selective permeability

Answer 84

Ability of a cell to regulate what can cross a membrane. // The property of a plasma membrane to allow certain molecules and ions to move through the membrane while restricting others.

Question 85

shielding

Answer 85

The effect on an electron of repulsion by electrons in lowerenergy orbitals that screen it from the full effects of nuclear charge. // An effect observed in NMR that causes a nucleus to absorb toward the right (upield) side of the chart. Shielding is caused by donation of electron density to the nucleus.

Question 86

simple diffusion

Answer 86

Passive transport process used when small nonpolar molecules cross the plasma membrane unassisted. // The movement of solute molecules across a membrane to a region of lower concentration, unassisted by a protein transporter.

Question 87

Southern blot

Answer 87

A DNA hybridization procedure in which one or more specific DNA fragments are detected in a larger population by hybridization to a complementary, labeled nucleic acid probe. // The transfer of DNA fragments from an electrophoretic gel to a cellulose or nylon membrane by capillary action.

Question 88

Sphingomyelin

Answer 88

A phosphosphingolipid. // Phospholipids that have sphingosine as the backbone rather than glycerol.

Question 89

steatorrhea

Answer 89

Presence of fatty stools due to fat malabsorption. stellate cell The major liver cell type involved in the development of liver fibrosis. Stellate cells are also early lipid storing cells of the liver.

Question 90

subunit vaccine

Answer 90

A vaccine consisting of an antigenetic fragment. // A vaccine formulated with purifi ed components of virus particles, rather than intact virus particles. (Chapter 8)

Question 91

synteny

Answer 91

Conserved gene order along the chromosomes of different species. // The occurrence of two loci on the same chromosome, without regard to the distance between them.

Question 92

Termination codon

Answer 92

Codons at which translation of an mRNA ceases, with release of both the nascent protein and ribosomes. (Chapter 11) // UAA, UAG, and UGA; in protein synthesis, these codons signal the termination of a polypeptide chain. Also known as stop codons.

Question 93

TH1 cell

Answer 93

A type of effector helper T cell that secretes interferon-γ to help activate macrophages and induces B cells to switch the class of antibody they make.

Question 94

thrombus

Answer 94

(throm′bŭs) Blood clot formed within a blood vessel during hypercoagulation; may become an embolus if dislodged. // A clot formed in an intact blood vessel.

Question 95

tract

Answer 95

(trakt) Bundle of axons in the central nervous system. // A collection of central nervous system axons with a common site of origin and a common destination.

Question 96

transgenic organism

Answer 96

Plant or animal that has stably incorporated one or more genes from another cell or organism (through insertion, deletion, and/or replacement) and can pass them on to successive generations.

Question 97

tropomyosin

Answer 97

A muscle protein that binds to actin during muscle contraction. // A long, thin, fibrous protein associated with actin microfilaments.

Question 98

unsaturated fatty acid // unsaturated

Answer 98

A fatty acid containing one or more double bonds. // A fatty acid with one or more double bonds. // A fatty acid that contains one or more double bonds.

Question 99

valence bond theory

Answer 99

An advanced model of chemical bonding in which electrons reside in quantummechanical orbitals localized on individual atoms that are a hybridized blend of standard atomic orbitals; chemical bonds result from an overlap of these orbitals. // A bonding theory that describes a covalent bond as resulting from the overlap of two atomic orbitals.

Question 100

Vitamin B

Answer 100

Original antiberiberi factor; now known to be a mixture of factors and designated as the vitamin B complex

Question 101

wave function (ψ)

Answer 101

A solution to the wave equation for deining the behavior of an electron in an atom. The square of the wave function deines the shape of an orbital. // A mathematical function that describes the wavelike nature of the electron.

Question 102

zinc finger

Answer 102

A specialized protein motif involved in DNA recognition by some DNAbinding proteins; characterized by a single atom of zinc coordinated to four Cys residues or to two His and two Cys residues.