BIO - TERMS - FREQUENCY > 1 PT 5 Flashcards
abetalipoproteinemia
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.
activator protein 1 (AP-1)
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.
afferent
(af′er-ent) Inflowing or going toward a center. // An axon coursing toward and innervating a given structure. See also efferent.
Alkylating agent
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.
Amnion
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.
Aneuploid
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.
antiport
Cotransport of two solutes across a membrane in opposite directions. // The coupled membrane transport of two substrates in opposite directions.
Arthus reaction
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.
Attenuation
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.
auxotroph
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.
benthic // benthic zone
The sediment at the bottom of a body of water. // Referring to the bottom of a water body (running waters, lakes, oceans).
Bivalent
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.
brown adipose tissue (BAT)
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.
carbanion
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.
Catalase
A hydrogen peroxide–degrading enzyme. // An enzyme that breaks down hydrogen peroxide: 2H2O2 → 2H2O + O2
chain reaction
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.
chiral compound
A compound that contains an asymmetric center (chiral atom or chiral center) and thus can occur in two nonsuperposable mirror-image forms (enantiomers).
Cirrhosis
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.
Cointegrate
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.
compound
A substance composed of two or more different chemical elements. // A substance composed of two or more elements in fixed, definite proportions.
Connexin
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.”
Cori cycle
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.
Cytochrome P-450
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.
dermis
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.
differential interference contrast (DIC) microscope
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.
DNA chip (“microarray”)
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.
Dominant
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.
ectoderm
(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.
electron configuration
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.
endolymph
(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.
ephrin
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.
Etiology
Th e cause or causes of a disease // The study of the cause of a disease.
fat
Solid triacylglycerols derived from an animal source. // Energy-storage lipid in cells. Composed of triglycerides— fatty acids esterified with glycerol.
first law of thermodynamics
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.
follicle
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.
G2 phase
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.
gastrulation
(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).
glomerulus
(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.
Glycoside
A cyclic acetal formed by reaction of a sugar with another alcohol. // A chemical substance that yields at least one simple sugar on hydrolysis.
granum (plural: grana)
Stack of thylakoid membrane. // Stacks of thylakoids, flattened membranous sacs or disks, in chloroplasts.
Haplotype
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.
Heparin
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.
homologous chromosomes (homologs)
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.
hydronium ion
The hydrated hydrogen ion (H3O1). // H3O+; the ion formed from the association of a water molecule with an H+ ion donated by an acid.
hypertonic solution
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.
immunoblotting
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.
in situ hybridization
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.
inflammatory bowel disease (IBD)
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.
insertion sequence (IS)
The simplest kind of transposon. // A mobile element in prokaryotes that contains a gene for transposase.
iron-sulfur protein
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.
Ketones (R2CO)
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.
lateral
(lat′er-ăl) Away from the midline. // An anatomical reference meaning away from the midline.
levorotatory
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.
lipopolysaccharide (LPS)
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.
lymph
(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.
medial
(mē′dē-ăl) Toward the midline. // An anatomical reference meaning toward the midline.
Methylation (of DNA and RNA) // Methylation reaction
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.
Mitogen-activated protein (MAP) kinases // mitogen-activated protein kinases (MAPKs)
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.
Morphogen
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.
Myc
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.
nephron
(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.
neurulation
(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.
nonbonding electrons
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.
Nucleocapsid
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)
Oogonium (pl, oogonia)
(ō-ō-gō′nē-ŭm; pl., oogonia) Diploid germ cell that forms oocytes. // A germ cell of the female animal before meiosis begins.
Organophosphate
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.
Pair-rule gene
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.
Parkinson disease
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.
perilymph
(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.
phase-contrast microscope
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.
photosynthesis
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).
plant hormones (phytohormones)
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).
polycistronic mRNA
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.
Population (effective)
Breeding members of the population.
primary immune response
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.
proton-motive force
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.
R-loops
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.
recombinant vaccine
A vaccine made by recombinant DNA techniques. // A vaccine produced by recombinant DNA technology. (Chapter 8)
regulatory gene // regulator gene
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.
residue
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.
retinoblastoma protein (Rb protein // pRb)
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.
sagittal plane // sagittal
(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.
schizophrenia
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.
segment-polarity gene
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.
severe combined immunodeficiency (SCID)
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.
signal-recognition particle (SRP)
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.
somite
(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.
spermatogenesis
(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.
STAT (signal transducer and activator of transcription)
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.
stroma
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.
syncytium
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.
tendon
(ten′dŏn) Cord of dense regular connective tissue that connects muscle to bone. // Connective tissue that connects muscle to bone.
tetrahydrofolate
The reduced, active coenzyme form of the vitamin folate. // The coenzyme form of folic acid; acts as a carrier of one-carbon units.
thiamine pyrophosphate (TPP)
A prosthetic group that transfers carbonyl compounds. // The active coenzyme form of vitamin B1; involved in aldehyde transfer reactions.
toxin
Any poisonous substance produced by a microorganism. // A harmful biogenic substance or agent causing injury in living organisms as a result of physicochemical interactions.
transgenic
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.
triple bond
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.
uncoating
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)
V(D)J recombination
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.
virulence
The degree of pathogenicity of a microorganism. // Th e relative capacity of a viral infection to cause disease. (Chapter 5)
volume (V)
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.
xeroderma pigmentosum
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.
