BIO - TERMS - FREQUENCY > 1 PT 5

Question 1

abetalipoproteinemia

Answer 1

An inherited inability to form chylomicrons and very-low-density lipoprotein (VLDL). // A recessive genetic disorder that results in the malabsorption of fat and fat-soluble vitamins from food. It is due to a failure to produce apolipoprotein B, which is needed for the formation of chylomicrons and very low-density lipoproteins.

Question 2

activator protein 1 (AP-1)

Answer 2

A transcription factor formed as one of the outcomes of intracellular signaling by antigen receptors of lymphocytes. active immunization Immunization with antigen to provoke adaptive immunity.

Question 3

afferent

Answer 3

(af′er-ent) Inflowing or going toward a center. // An axon coursing toward and innervating a given structure. See also efferent.

Question 4

Alkylating agent

Answer 4

Chemicals that transfer alkyl (methyl, ethyl, and so on) groups to the bases in DNA. // Reactive secondary metabolite which introduces an alkyl substituent into DNA, proteins or other molecules.

Question 5

Amnion

Answer 5

The thin membrane that lines the fl uid-fi lled sac in which the embryo develops in higher vertebrates. // (am′nē-on) Extraembryonic membrane that envelops the embryo and fetus, and secretes amniotic fluid.

Question 6

Aneuploid

Answer 6

Abnormal in chromosome morphology and number. (Chapter 2) // An organism or cell having a chromosome number that is not an exact multiple of the monoploid (n) with one genome, that is, hyperploid, higher (for example, 2n + 1), or hypoploid, lower (for example, 2n − 1). Also applied to cases where part of a chromosome is duplicated or deficient.

Question 7

antiport

Answer 7

Cotransport of two solutes across a membrane in opposite directions. // The coupled membrane transport of two substrates in opposite directions.

Question 8

Arthus reaction

Answer 8

Inflammation and necrosis at the site of injection of foreign serum, due to immune complex formation. // A local skin reaction that occurs when a sensitized individual with IgG antibodies against a particular antigen is challenged by injection of the antigen into the dermis. Immune complexes of the antigen with IgG antibodies in the extracellular spaces in the dermis activate complement and phagocytic cells to produce a local inflammatory response.

Question 9

Attenuation

Answer 9

A mechanism for controlling gene expression in prokaryotes that involves premature termination of transcription. // The process by which human or animal pathogens are modified by growth in culture so that they can grow in their host and induce immunity without producing serious clinical disease.

Question 10

auxotroph

Answer 10

A mutant microorganism with a nutritional requirement that is absent in the parent. // A mutant microorganism (for example, bacterium or yeast) that will not grow on a minimal medium but that requires the addition of some compound such as an amino acid or a vitamin.

Question 11

benthic // benthic zone

Answer 11

The sediment at the bottom of a body of water. // Referring to the bottom of a water body (running waters, lakes, oceans).

Question 12

Bivalent

Answer 12

A pair of synapsed or associated homologous chromosomes that have undergone the duplication process to form a group of four chromatids. // A four-chromatid structure formed during meiosis, consisting of a duplicated chromosome tightly paired with its homologous duplicated chromosome.

Question 13

brown adipose tissue (BAT)

Answer 13

Specialized adipose tissue that can generate additional heat to maintain body temperature. Typically found in infants but not in significant amounts in adults. // Thermogenic adipose tissue rich in mitochondria that contain the uncoupling protein thermogenin, which uncouples electron transfer through the respiratory chain from ATP synthesis. Compare white adipose tissue.

Question 14

carbanion

Answer 14

A negatively charged carbon atom. // A carbon anion, or substance that contains a trivalent, negatively charged carbon atom (R3C:-). Alkyl carbanions are sp3-hybridized and have eight electrons in the outer shell of the negatively charged carbon.

Question 15

Catalase

Answer 15

A hydrogen peroxide–degrading enzyme. // An enzyme that breaks down hydrogen peroxide: 2H2O2 → 2H2O + O2

Question 16

chain reaction

Answer 16

A series of reactions in which previous reactions cause future ones; in a fission bomb, neutrons produced by the fission of one uranium nucleus induce fission in other uranium nuclei. // A reaction that, once initiated, sustains itself in an endlessly repeating cycle of propagation steps. The radical chlorination of alkanes is an example of a chain reaction that is initiated by irradiation with light and then continues in a series of propa gation steps.

Question 17

chiral compound

Answer 17

A compound that contains an asymmetric center (chiral atom or chiral center) and thus can occur in two nonsuperposable mirror-image forms (enantiomers).

Question 18

Cirrhosis

Answer 18

Fibrous degeneration of the liver. // Hardening and scarring of the liver. cis On the same side of a double bond. In terms of fatty acids, each hydrogen atom is on the same side of a double bond.

Question 19

Cointegrate

Answer 19

A DNA molecule formed by the fusion of two different DNA molecules, usually mediated by a transposable element. // An intermediate in the migration of certain DNA transposons in which the donor DNA and target DNA are covalently attached.

Question 20

compound

Answer 20

A substance composed of two or more different chemical elements. // A substance composed of two or more elements in fixed, definite proportions.

Question 21

Connexin

Answer 21

A channel-forming transmembrane protein in gap junctions. // Protein component of gap junctions, a four-pass transmembrane protein. Six connexins assemble in the plasma membrane to form a connexon, or “hemichannel.”

Question 22

Cori cycle

Answer 22

The shuttling of glucose and lactate between muscle and liver during physical exercise. // The phases in the metabolism of carbohydrate: (1) glycogenolysis in the liver; (2) passage of glucose into the circulation; (3) deposition of glucose in muscles as glycogen; and (4) glycogenolysis during muscular activity and conversion to lactate, which is converted to glycogen in the liver. Also called the lactic acid cycle.

Question 23

Cytochrome P-450

Answer 23

A large family of heme-containing proteins that participate in monooxygenase reactions. // A family of hemecontaining enzymes, with a characteristic absorption band at 450 nm, that participate in biological hydroxylations with O2.

Question 24

dermis

Answer 24

The inner portion of the skin. // (der′mis) Connective tissue layer of skin internal to the epidermis; contains blood and lymph vessels, nerves and nerve endings, glands, and usually hair follicles.

Question 25

differential interference contrast (DIC) microscope

Answer 25

An instrument that provides a three-dimensional, magnified image. // Type of light microscope that exploits the interference effects that occur when light passes through parts of a cell of different refractive indices. Used to view unstained living cells.

Question 26

DNA chip (“microarray”)

Answer 26

Informal term for a DNA microarray, referring to the small size of typical microarrays. // A silica wafer that holds DNA probes; used to recognize DNA in samples being tested.

Question 27

Dominant

Answer 27

Determining the phenotype in the heterozygous (as well as the homozygous) state. // A term applied to an allele that is manifested to the exclusion of a different allele in a heterozygote.

Question 28

ectoderm

Answer 28

(ek′tō-derm) Outermost of the three primary germ layers of the embryo. // Embryonic epithelial tissue that is the precursor of the epidermis and nervous system.

Question 29

electron configuration

Answer 29

A list of the orbitals occupied by electrons in an atom. // A notation that shows the particular orbitals that are occupied by electrons in an atom.

Question 30

endolymph

Answer 30

(en′dō-limf) Fluid within the membranous labyrinth of the inner ear. // The fluid that fills the scala media in the cochlea of the inner ear, containing high K and low Na concentrations.

Question 31

ephrin

Answer 31

A protein secreted by neurons in many parts of the developing nervous system that helps establish topographic axonal connections. // One of a family of membrane-bound protein ligands for the Eph receptor tyrosine kinases (RTKs) that, among many other functions, stimulate repulsion or attraction responses that guide the migration of cells and nerve cell axons during animal development.

Question 32

Etiology

Answer 32

Th e cause or causes of a disease // The study of the cause of a disease.

Question 33

fat

Answer 33

Solid triacylglycerols derived from an animal source. // Energy-storage lipid in cells. Composed of triglycerides— fatty acids esterified with glycerol.

Question 34

first law of thermodynamics

Answer 34

The law stating that the total energy of the universe is constant. // The law stating that, in all processes, the total energy of the universe remains constant.

Question 35

follicle

Answer 35

Roughly spherical group of cells enclosing a cavity. // An area of predominantly B cells in a peripheral lymphoid organ, such as a lymph node, which also contains follicular dendritic cells.

Question 36

G2 phase

Answer 36

The time between S phase and mitosis. // Gap 2 phase of the eukaryotic cell-division cycle, between the end of DNA synthesis and the beginning of mitosis.

Question 37

gastrulation

Answer 37

(gas-trū-lā′shŭn) Formation of the three primary germ layers. // Important stage in animal embryogenesis during which the embryo is transformed from a ball of cells to a structure with a gut (a gastrula).

Question 38

glomerulus

Answer 38

(glō-mer′yū-lŭs) A capillary network within the renal corpuscle in a kidney. // A cluster of neurons in the olfactory bulb that receives input from olfactory receptor neurons.

Question 39

Glycoside

Answer 39

A cyclic acetal formed by reaction of a sugar with another alcohol. // A chemical substance that yields at least one simple sugar on hydrolysis.

Question 40

granum (plural: grana)

Answer 40

Stack of thylakoid membrane. // Stacks of thylakoids, flattened membranous sacs or disks, in chloroplasts.

Question 41

Haplotype

Answer 41

A set of linked genetic variants, especially single-nucleotide polymorphisms (SNPs), on a chromosome. // A combination of alleles of different genes located sufficiently close together on a chromosome that they tend to be inherited together.

Question 42

Heparin

Answer 42

A sulfated glycosaminoglycan (GAG) made by mast cells and basophils. // (hep′a-rı̆n) Chemical that prevents blood clot formation; released by basophils and mast cells.

Question 43

homologous chromosomes (homologs)

Answer 43

The maternal and paternal copies of a particular chromosome in a diploid cell. // Chromosomes that occur in pairs and are generally similar in size and shape, one having come from the male parent and the other from the female parent. Such chromosomes contain the same array of genes.

Question 44

hydronium ion

Answer 44

The hydrated hydrogen ion (H3O1). // H3O+; the ion formed from the association of a water molecule with an H+ ion donated by an acid.

Question 45

hypertonic solution

Answer 45

A solution that has a higher concentration of solutes than an isotonic solution. // Solution with a lower water concentration and higher solute concentration than that of the cytosol.

Question 46

immunoblotting

Answer 46

Western blotting // A technique that employs antibodies to detect the presence of a protein in a biological sample after the proteins in the sample have been separated by gel electrophoresis, transferred to a membrane and immobilized; also called Western blotting.

Question 47

in situ hybridization

Answer 47

A method for localizing strands of messenger RNA within cells. // A method for determining the location of specific DNA sequences in chromosomes by hybridizing labeled DNA or RNA to denatured DNA in chromosome preparations and visualizing the hybridized probe by autoradiography or fluorescence microscopy.

Question 48

inflammatory bowel disease (IBD)

Answer 48

General name for a set of inflammatory conditions in the gut, such as Crohn’s disease and colitis, that have an immunological component. // A general term in reference to Crohn’s disease or ulcerative colitis. insensible water loss The daily loss of water through the lungs, skin, and feces.

Question 49

insertion sequence (IS)

Answer 49

The simplest kind of transposon. // A mobile element in prokaryotes that contains a gene for transposase.

Question 50

iron-sulfur protein

Answer 50

Nonheme iron proteins that participate in electron transfer reactions. // One of a large family of electron-transfer proteins in which the electron carrier is one or more iron ions associated with two or more sulfur atoms of Cys residues or of inorganic sulfide.

Question 51

Ketones (R2CO)

Answer 51

A class of compounds with two organic substituents bonded to a carbonyl group, R2C=O. // A member of the family of organic compounds that contain a carbonyl functional group (C=O) bonded to two R groups, neither of which is a hydrogen atom.

Question 52

lateral

Answer 52

(lat′er-ăl) Away from the midline. // An anatomical reference meaning away from the midline.

Question 53

levorotatory

Answer 53

Being capable of rotating the polarization of light counterclockwise. // An optically active substance that rotates the plane of polarization of plane-polarized light in a lefthanded (counterclockwise) direction.

Question 54

lipopolysaccharide (LPS)

Answer 54

A molecule consisting of a lipid and a polysaccharide, forming the outer membrane of gram-negative cell walls. // The surface lipopolysaccharide of Gram-negative bacteria, which stimulates TLR-4 on macrophages and dendritic cells.

Question 55

lymph

Answer 55

(limf) Usually transparent fluid found in lymph vessels; derived from interstitial fluid. // The extracellular fluid that accumulates in tissues and is drained by lymphatic vessels that carry it through the lymphatic system to the thoracic duct, which returns it to the blood.

Question 56

medial

Answer 56

(mē′dē-ăl) Toward the midline. // An anatomical reference meaning toward the midline.

Question 57

Methylation (of DNA and RNA) // Methylation reaction

Answer 57

The addition of a methyl (–CH3) group(s) to one or more of the nucleotides in a nucleic acid. // Transfer of a methyl group from one molecule (often S-adenosyl methionine [SAM]) to another.

Question 58

Mitogen-activated protein (MAP) kinases // mitogen-activated protein kinases (MAPKs)

Answer 58

A family of protein kinases that are activated in response to growth factors or stress. // A series of protein kinases that become phosphorylated and activated on cellular stimulation by a variety of ligands, and lead to new gene expression by phosphorylating key transcription factors. The MAPKs are part of many signaling pathways, especially those leading to cell proliferation, and have different names in different organisms.

Question 59

Morphogen

Answer 59

A substance that stimulates the development of form or structure in an organism. // Diffusible signal molecule that can impose a pattern on a field of cells by causing cells in different places to adopt different fates.

Question 60

Myc

Answer 60

Transcription regulatory protein that is activated when a cell is stimulated to grow and divide by extracellular signals. It activates the transcription of many genes, including those that stimulate cell growth.

Question 61

nephron

Answer 61

(nef′ron) Functional filtration unit in the kidney; composed of a renal corpuscle, a proximal and distal convoluted tubule, and nephron loop. // The microscopic functional unit of a kidney. nervous tissue Type of tissue composed of nerve cells ( neurons) that transmits electric impulses throughout the body.

Question 62

neurulation

Answer 62

(nū′rū-lā′shun) Formation of the neural plate and its closure to form the neural tube. // The formation of the neural tube from the neural ectoderm during embryonic development.

Question 63

nonbonding electrons

Answer 63

Electrons in a Lewis structure that are not in a chemical bond; also called lone pair electrons. // Valence electrons that are not used in forming covalent bonds.

Question 64

Nucleocapsid

Answer 64

The particle formed from viral nucleic acid and protein coat. // A nucleic acid-protein assembly packaged within the virus particle; the term is used when this complex is a discrete substructure of a complex particle. (Chapter 4)

Question 65

Oogonium (pl, oogonia)

Answer 65

(ō-ō-gō′nē-ŭm; pl., oogonia) Diploid germ cell that forms oocytes. // A germ cell of the female animal before meiosis begins.

Question 66

Organophosphate

Answer 66

Irreversible inhibitors of acetylcholinesterase; used as pesticides and as nerve gases. // A compound that contains a phosphorus atom bonded to four oxygens, with one of the oxygens also bonded to carbon.

Question 67

Pair-rule gene

Answer 67

A gene that influences the formation of body segments in Drosophila. // In Drosophila development, a gene expressed in a series of regular transverse stripes along the body of the embryo and which helps to determine its segments.

Question 68

Parkinson disease

Answer 68

Age-related degeneration of dopamine neurons, causing a motor disorder. // A movement disorder caused by damage to the substantia nigra, characterized by paucity of movement, difficulty in initiating willed movement, and resting tremor.

Question 69

perilymph

Answer 69

(per′i-limf) Fluid within the osseous labyrinth that surrounds and protects the membranous labyrinth. // The fluid that fills the scala vestibuli and scala tympani in the cochlea in the inner ear, containing low K and high Na concentrations.

Question 70

phase-contrast microscope

Answer 70

A compound light microscope that allows examination of structures inside cells through the use of a special condenser. // Type of light microscope that exploits the interference effects that occur when light passes through material of different refractive indices. Used to view living cells.

Question 71

photosynthesis

Answer 71

The use of light energy to produce carbohydrates from carbon dioxide and a reducing agent such as water. Compare oxygenic photosynthesis. // The conversion of light energy from the sun into chemical energy; the light-fueled synthesis of carbohydrate from carbon dioxide (CO2).

Question 72

plant hormones (phytohormones)

Answer 72

Signaling substances generated by plants that serve as developmental cues or are part of signal processing events to mediate adaptation to a perceived exogenous stimulus. // Water-soluble or volatile compounds involved in short- or long-distance signaling in plants. Are either produced within the responding tissue or are transported over long distances from the site of synthesis to that of action. Examples are cytokinins, auxins, ethylene, gibberellic acid, oxylipins, salicylic acid and methylesters of jasmonic and salicylic acid, ethane (volatiles).

Question 73

polycistronic mRNA

Answer 73

A contiguous mRNA with more than two genes that can be translated into proteins. // A messenger RNA (mRNA) that has been transcribed from more than one gene.

Question 74

Population (effective)

Answer 74

Breeding members of the population.

Question 75

primary immune response

Answer 75

Adaptive immune response to an antigen that is made on first encounter with that antigen. // The adaptive immune response that follows the first exposure to a particular antigen.

Question 76

proton-motive force

Answer 76

The electrochemical potential inherent in a transmembrane gradient of H concentration; used in oxidative phosphorylation and photophosphorylation to drive ATP synthesis. // The force exerted by the electrochemical proton gradient that moves protons across a membrane.

Question 77

R-loops

Answer 77

A structure formed when transcribed RNA displaces the nontemplate strand of the DNA double helix at switch regions in the immunoglobulin constant-region gene cluster. R-loops are thought to promote class switch recombination. // Single-stranded DNA regions in RNA–DNA hybrids formed in vitro under conditions where RNA–DNA duplexes are more stable than DNA–DNA duplexes.

Question 78

recombinant vaccine

Answer 78

A vaccine made by recombinant DNA techniques. // A vaccine produced by recombinant DNA technology. (Chapter 8)

Question 79

regulatory gene // regulator gene

Answer 79

A gene that controls the rate of expression of another gene or genes. Example: The lacI gene produces a protein that controls the expression of the structural genes of the lac operon in Escherichia coli. // A gene that gives rise to a product involved in the regulation of the expression of another gene; for example, a gene encoding a repressor protein.

Question 80

residue

Answer 80

Amino acids in a protein chain. // A single unit in a polymer; for example, an amino acid in a polypeptide chain. The term reflects the fact that sugars, nucleotides, and amino acids lose a few atoms (generally the elements of water) when incorporated in their respective polymers.

Question 81

retinoblastoma protein (Rb protein // pRb)

Answer 81

The “guardian of the G1 checkpoint,” encoded by the retinoblastoma (RB1) tumor suppressor gene. // Tumor suppressor protein involved in the regulation of cell division. Mutated in the cancer retinoblastoma, as well as in many other tumors. Its normal activity is to regulate the eukaryotic cell cycle by binding to and inhibiting the E2F proteins, thus blocking progression to DNA replication and cell division.

Question 82

sagittal plane // sagittal

Answer 82

(saj′i-tăl) Relating to a plane cutting the body into a left and a right part. // An anatomical plane of section that is parallel to the midsagittal plane.

Question 83

schizophrenia

Answer 83

A mental disorder characterized by a loss of contact with reality; fragmentation and disruption of thought, perception, mood, and movement; delusions; hallucinations; and disordered memory. // A group of severe psychiatric diseases in which new mutations are frequently observed.

Question 84

segment-polarity gene

Answer 84

In Drosophila development, a gene involved in specifying the anteroposterior organization of each body segment. // A group of genes whose products define the anterior and posterior compartments in each of the segments that form along the anterior–posterior axis of Drosophila embryos.

Question 85

severe combined immunodeficiency (SCID)

Answer 85

Inherited diseases with combined B-cell and T-cell defects. // Type of immune deficiency (due to various causes) in which both B-cell (antibody) and T-cell responses are lacking; it is fatal if not treated.

Question 86

signal-recognition particle (SRP)

Answer 86

A cytoplasmic ribonucleoprotein that binds the signal sequence. // Ribonucleoprotein particle that binds an ER signal sequence on a partially synthesized polypeptide chain and directs the polypeptide and its attached ribosome to the endoplasmic reticulum.

Question 87

somite

Answer 87

(sō′mı̄t) One of the paired segments consisting of cell masses formed in the early embryonic mesoderm on the sides of the neural tube. // One of a series of paired blocks of mesoderm that form during early development and lie on either side of the notochord in a vertebrate embryo. They give rise to the segments of the body axis, including the vertebrae, muscles, and associated connective tissue.

Question 88

spermatogenesis

Answer 88

(sper′mă-tō- jen′ĕ-sis) Process by which stem cells called spermatogonia become sperm. // The process by which maturation of the gametes (sperm) of the male takes place.

Question 89

STAT (signal transducer and activator of transcription)

Answer 89

Latent transcription regulator that is activated by phosphorylation by Janus kinases (JAKs) and enters the nucleus in response to signaling from receptors of the cytokine receptor family. // A family of seven transcription factors activated by many cytokine and growth factor receptors.

Question 90

stroma

Answer 90

The space and aqueous solution enclosed within the inner membrane of a chloroplast, not including the contents in the thylakoid membranes. // (1) “Bedding”: the connective tissue in which a glandular or other epithelium is embedded. Stromal cells provide the environment necessary for the development of other cells within the tissue. (2) The large interior space of a chloroplast, containing enzymes that incorporate CO2 into sugars.

Question 91

syncytium

Answer 91

Mass of cytoplasm containing many nuclei enclosed by a single plasma membrane. Typically the result either of cell fusion or of a series of incomplete division cycles in which the nuclei divide but the cell does not. // A multinucleated giant cell resulting from certain viral infections.

Question 92

tendon

Answer 92

(ten′dŏn) Cord of dense regular connective tissue that connects muscle to bone. // Connective tissue that connects muscle to bone.

Question 93

tetrahydrofolate

Answer 93

The reduced, active coenzyme form of the vitamin folate. // The coenzyme form of folic acid; acts as a carrier of one-carbon units.

Question 94

thiamine pyrophosphate (TPP)

Answer 94

A prosthetic group that transfers carbonyl compounds. // The active coenzyme form of vitamin B1; involved in aldehyde transfer reactions.

Question 95

toxin

Answer 95

Any poisonous substance produced by a microorganism. // A harmful biogenic substance or agent causing injury in living organisms as a result of physicochemical interactions.

Question 96

transgenic

Answer 96

Describes an organism that has genes from another organism incorporated in its genome as a result of recombinant DNA procedures. // A term applied to organisms that have been altered by introducing DNA molecules into them.

Question 97

triple bond

Answer 97

The bond that forms when three electron pairs are shared between two atoms. // A type of covalent bond formed by sharing three electron pairs between atoms.

Question 98

uncoating

Answer 98

The separation of viral nucleic acid from its protein coat. // The release of viral nucleic acid from its protective protein coat or lipid envelope; in some cases, the liberated nucleic acid is still associated with viral proteins. (Chapter 5)

Question 99

V(D)J recombination

Answer 99

Somatic recombination process by which gene segments are brought together to form a functional gene for a polypeptide chain of an immunoglobulin or T cell receptor. // The process exclusive to developing lymphocytes in vertebrates, that recombines different gene segments into sequences encoding complete protein chains of immunoglobulins and T-cell receptors.

Question 100

virulence

Answer 100

The degree of pathogenicity of a microorganism. // Th e relative capacity of a viral infection to cause disease. (Chapter 5)

Question 101

volume (V)

Answer 101

A quantitative element of training that can be measured as time or duration of training, the distance covered, the volume load of resistance training, or the number of repetitions performed. // A measure of space. Any unit of length, when cubed (raised to the third power), becomes a unit of volume.

Question 102

xeroderma pigmentosum

Answer 102

Several autosomal recessive diseases caused by defects in repair of ultraviolet light-induced DNA damage. Defects in Polη cause type V xeroderma pigmentosum. // An inherited defect of nucleotide excision repair, characterized by cutaneous photosensitivity.