BIO - TERMS - FREQUENCY > 1 PT 1

Question 1

3-hydroxy-3-methylglutaryl-co-enzyme A (HMG-CoA) reductase

Answer 1

The regulated enzyme of cholesterol synthesis. // Ratelimiting enzyme in the production of cholesterol and a target of cholesterollowering drugs such as the statins.

Question 2

acetylcholine // ACh

Answer 2

Neurotransmitter produced by the central and peripheral nervous systems. // An amine that serves as a neurotransmitter at many synapses in the peripheral and central nervous systems, including the neuromuscular junction.

Question 3

adenylyl cyclase (adenylate cyclase)

Answer 3

An enzyme that catalyzes the conversion of adenosine triphosphate (ATP) to cyclic adenosine monophosphate (cAMP), a second messenger. // Membrane-bound enzyme that catalyzes the formation of cyclic AMP from ATP. An important component of some intracellular signaling pathways.

Question 4

Aldehydes (RCHO)

Answer 4

A class of compounds containing the -CHO functional group. // A member of the family of organic compounds that contain a carbonyl functional group (C=O) bonded to two R groups, one of which is a hydrogen atom.

Question 5

Alternative pathway

Answer 5

One of three pathways in the complement system; activates the C3 and C5 convertases without going through the C1-C2-C4 complex. (Chapter 3) // A form of complement activation that is initiated by spontaneous hydrolysis of C3 and which uses factor B and factor D to form the unique C3 convertase C3bBb.

Question 6

Anabolic pathway

Answer 6

Biosynthetic pathway. // A pathway by which a metabolite is synthesized; a biosynthetic pathway.

Question 7

antidiuretic hormone (ADH)

Answer 7

Hormone released by the posterior pituitary gland; increases water reabsorption in the kidney and reduces urine production. // A peptide hormone produced by the hypothalamus that facilitates the reabsorption of water by the kidney tubules. Also known as vasopressin. anthocyanidin A class of purple to blue plant flavonoid pigments without sugar moieties attached that have potential health benefits such as cancer prevention as well as antiaging and anti-inflammatory effects.

Question 8

Apolipoprotein

Answer 8

Protein component of a lipoprotein.

Question 9

atomic mass unit (AMU)

Answer 9

A unit of mass for atomic and molecular weights. // A unit used to express the masses of atoms and subatomic particles, defined as 1/12 the mass of a carbon atom containing 6 protons and 6 neutrons.

Question 10

autophagosome

Answer 10

Organelle surrounded by a double membrane contains engulfed cytoplasmic cargo in the initial stages of autophagy. // A double bilayer membrane structure that functions in macroautophagy by engulfing cytoplasmic contents and fusing with lysosomes.

Question 11

bacteriocin

Answer 11

An antimicrobial peptide produced by bacteria that kills other bacteria. // Proteinaceous toxins produced by bacteria to inhibit the growth of similar or closely related bacterial strain(s).They are typically considered to be narrow spectrum antibiotics though this has been debated.

Question 12

Bilirubin

Answer 12

A yellow pigment formed from biliverdin. // (bil-i-rū′bin) Waste product derived from the breakdown of hemoglobin and excreted in bile.

Question 13

bond length

Answer 13

The average length of a bond between two particular atoms in a variety of compounds. // The equilibrium distance between the nuclei of two atoms that are bonded to each other.

Question 14

cancer

Answer 14

Various types of malignant cells that multiply out of control. // Disease involving a malignant neoplasm that can metastasize (spread to other organs).

Question 15

Carnitine

Answer 15

A coenzyme that carries long-chain fatty acids into the mitochondrion. // Essential for transport of fatty acyl CoA from cytoplasm to mitochondria for β oxidation; synthesized by most species except some insects, which require a dietary source for growth

Question 16

cerebellum

Answer 16

(ser-e-bel′ŭm) The second largest part of the brain; develops posteriorly to the pons in the metencephalon. // A structure derived from the rhombencephalon, attached to the brain stem at the pons; an important movement control center.

Question 17

chemoreceptor

Answer 17

Any sensory receptor selective for chemicals. // (kē′mō-rē-sep′tor) Peripheral sensory receptor or specialized cells within the brain that detect specific chemicals in a fluid; e.g., taste receptors.

Question 18

Cholestasis

Answer 18

Lack of bile flow. // Little or no bile secreted.

Question 19

cleavage

Answer 19

(klēv′ij) Series of mitotic cell divisions occurring in the zygote immediately following its fertilization. // (1) Physical splitting of a cell into two. (2) Specialized type of cell division seen in many early embryos whereby a large cell becomes subdivided into many smaller cells without growth.

Question 20

Competence (adj, competent)

Answer 20

Ability of a bacterial cell to incorporate DNA and become genetically transformed. // The physiological state in which a recipient cell can take and incorporate a large piece of donor DNA.

Question 21

conjugative plasmid

Answer 21

A prokaryotic plasmid that carries genes for sex pili and for transfer of the plasmid to another cell.

Question 22

contralateral

Answer 22

(kon-tră-lat′er-ăl) Relating to the opposite side. // An anatomical reference meaning on the opposite side of the midline.

Question 23

cyclic photophosphorylation

Answer 23

ATP synthesis driven by cyclic electron flow through photosystem I. // The movement of an electron from chlorophyll through a series of electron acceptors and back to chlorophyll; anoxygenic; purple and green bacterial photophosphorylation.

Question 24

Degeneracy (of the genetic code)

Answer 24

The specification of an amino acid by more than one codon. // Redundancy of the genetic code; that is, most amino acids are encoded by several codons.

Question 25

diabetes mellitus

Answer 25

(me-lı̄′tŭs) Disease involving reduced insulin release or reduced tissue response to insulin; leads to elevated blood and urine glucose levels. // A group of metabolic diseases with symptoms that result from a deficiency in insulin production or utilization; characterized by a failure in glucose transport from the blood into cells at normal glucose concentrations.

Question 26

dislocation

Answer 26

(dis-lō-kā′shŭn) A joint injury where there is complete displacement of a bone from its normal position. // In reference to viral defense mechanisms, the degradation of newly synthesized MHC class I molecules by viral proteins.

Question 27

DNA primase

Answer 27

Enzyme that synthesizes a short strand of RNA on a DNA template, producing a primer for DNA synthesis. // An enzyme that catalyzes the synthesis of short strands of RNA that initiate the synthesis of DNA strands.

Question 28

Dynein

Answer 28

The ATPase that moves cilia and flagella. // Large motor protein that undergoes ATP-dependent movement along microtubules.

Question 29

electrical current

Answer 29

The flow of electric charge. // The rate of movement of electrical charge, represented by the symbol I and measured in amperes (amp).

Question 30

element

Answer 30

Substance composed of only one type of atom. // A substance that cannot be chemically broken down into simpler substances.

Question 31

endotoxin

Answer 31

Part of the outer portion of the cell wall (lipid A) of most gram- negative bacteria; released on destruction of the cell. // Toxins derived from bacterial cell walls released by damaged cells. They can potently induce cytokine synthesis and in large amounts can cause a systemic reaction called septic shock or endotoxic shock.

Question 32

essential fatty acid

Answer 32

The group of polyunsaturated fatty acids produced by plants, but not by humans; required in the human diet. // A fatty acid needed by the body that must be supplied by the diet because the tissues are unable to synthesize it.

Question 33

Fab // Fab fragment

Answer 33

The antigen-binding fragment of immunoglobulins. // Antibody fragment composed of a single antigen-binding arm of an antibody without the Fc region, produced by cleavage of IgG by the enzyme papain. It contains the complete light chain plus the amino-terminal variable region and first constant region of the heavy chain, held together by an interchain disulfide bond.

Question 34

Fiber

Answer 34

A thin thread produced by extruding a molten polymer through small holes in a die. // Indigestible fibrous structural molecule found in plant tissue; includes indigestible straight and branchedchain polysaccharides as well as lignin.

Question 35

fluorescence microscope

Answer 35

A microscope that uses an ultraviolet light source to illuminate specimens that will fluoresce. // Microscope designed to view material stained with fluorescent dyes or proteins. Similar to a light microscope but the illuminating light is passed through one set of filters before the specimen, to select those wavelengths that excite the dye, and through another set of filters before it reaches the eye, to select only those wavelengths emitted when the dye fluoresces.

Question 36

fructan

Answer 36

Are polymers of fructose usually with a sucrose molecule at the end. // A class of fructose-based polymers of varying length that includes inulin, oligofructose, and fructooligosaccharides (FOS).

Question 37

gamma motor neuron

Answer 37

A motor neuron that innervates intrafusal muscle fibers.

Question 38

genome-wide association studies (GWASs)

Answer 38

A study that relates a large number of DNA variants to a disease or other phenotype. // Genetic association studies in the general population that look for a correlation between disease frequency and variant alleles by scanning the genomes of many people for the presence of informative single-nucleotide polymorphisms (SNPs).

Question 39

glycocalyx

Answer 39

A gelatinous polymer surrounding a cell. // (glı̄-kō-kā′liks) Carbohydrate coating on the apical surface of cells formed by glycolipids and glycoproteins.

Question 40

Graft copolymer

Answer 40

Linear heteropolymers with branches of one type of monomer “hung” from a main chain consisting of another homopolymer. // Copolymers in which homopolymer branches of one monomer unit are “grafted” onto a homopolymer chain of another monomer unit.

Question 41

gustation

Answer 41

(gŭs-tā′shŭn) Sense of taste.

Question 42

Hemolysis

Answer 42

Destruction of erythrocytes. // (hē-mol′i-sis) The process of rupture and destruction of erythrocytes.

Question 43

histology

Answer 43

(his-tol′ō-jē) Study of tissues. // The microscopic study of the structure of tissues.

Question 44

Hybrid orbital

Answer 44

Orbitals formed from the combination of standard atomic orbitals that correspond more closely to the actual distribution of electrons in a chemically bonded atom. // An orbital derived from a combination of atomic orbitals. Hybrid orbitals, such as the sp3, sp2, and sp hybrids of carbon, are strongly directed and form stronger bonds than atomic orbitals do.

Question 45

hyper IgM syndrome

Answer 45

A group of genetic diseases in which there is overproduction of IgM antibody, among other symptoms. They are due to defects in various genes for proteins involved in class switching such as CD40 ligand and the enzyme AID. See activation-induced cytidine deaminase, CD40 ligand deficiency.

Question 46

hypotonic solution

Answer 46

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

Question 47

immunotoxin

Answer 47

An immunotherapeutic agent consisting of a poison bound to a monoclonal antibody. // Antibodies that are chemically coupled to toxic proteins usually derived from plants or microbes. The antibody targets the toxin moiety to the required cells.

Question 48

inducer

Answer 48

A signal molecule that, when bound to a regulatory protein, produces an increase in the expression of a given gene. // A substance of low molecular weight that is bound by a repressor to produce a complex that can no longer bind to the operator; thus, the presence of the inducer turns on the expression of the gene(s) controlled by the operator.

Question 49

innate immunity

Answer 49

Host defenses that afford protection against any kind of pathogen. See also adaptive immunity. // The various innate resistance mechanisms that are encountered first by a pathogen, before adaptive immunity is induced, such as anatomical barriers, antimicrobial peptides, the complement system, and macrophages and neutrophils carrying nonspecific pathogen-recognition receptors. Innate immunity is present in all individuals at all times, does not increase with repeated exposure to a given pathogen, and discriminates between groups of similar pathogens, rather than responding to a particular pathogen. Cf. adaptive immunity.

Question 50

interneuron

Answer 50

(in′ter-nū′ron) Type of neuron that resides completely within the CNS and coordinates activity between sensory and motor neurons. // Any neuron that is not a sensory or motor neuron; also describes a CNS neuron whose axon does not leave the structure in which it resides.

Question 51

J chain

Answer 51

A polypeptide in polymeric immunoglobulins. // Small polypeptide chain made by B cells that attaches to polymeric immunoglobulins IgM and IgA by disulfide bonds, and is essential for formation of the binding site for the polymeric immunoglobulin receptor.

Question 52

Lactate dehydrogenase

Answer 52

The enzyme that interconverts pyruvate and lactate. // An enzyme contained in the glycolytic energy system that converts pyruvate to lactate.

Question 53

lemniscus

Answer 53

A tract that meanders through the brain like a ribbon. // (lem-nis′kŭs; pl., lemnisci, -nis′ı̄) Bundle of axons ascending from sensory relay nuclei to the thalamus.

Question 54

Linkage

Answer 54

The tendency of different genes to be inherited together because they are located on the same chromosome. // In ligand binding, the conformational coupling between two separate ligand-binding sites on a protein, such that a conformational change in the protein induced by binding of one ligand affects the binding of a second ligand.

Question 55

long-term depression (LTD)

Answer 55

A long-lasting decrease in the effectiveness of synaptic transmission that follows certain types of conditioning stimulation. // A long-lasting (hours or more) decrease in the sensitivity of certain synapses in the brain triggered by NMDA receptor activation. As the opposing process to long-term potentiation, it is thought to be involved in learning and memory.

Question 56

Maple syrup urine disease

Answer 56

An inborn error of branched-chain amino acid metabolism, causing mental and neurological deficits. // An inborn error of metabolism where the branched-chain amino acids are unable to be catabolized due to a defect in the enzyme branchedchain a-keto acid dehydrogenase complex. The inability to degrade the amino acids results in the accumulation of ketoacids in tissues and plasma, which leads to a number of brain-related disorders.

Question 57

Metagenomic analysis

Answer 57

Sequencing of samples recovered directly from the environment, and containing many genomes. (Chapter 1) // Nucleic acid sequencing of samples recovered directly from the environment, and comprising multiple genomes. (Chapter 10)

Question 58

microelectrode

Answer 58

A piece of fine glass tubing, pulled to an even finer tip, that is used to inject electric current into cells or to study the intracellular concentrations of common inorganic ions (such as H+, Na+, K+, Cl–, and Ca2+) in a single living cell by insertion of its tip directly into the cell interior through the plasma membrane. // A probe used to measure the electrical activity of cells. Microelectrodes have a very fi ne tip and can be fashioned from etched metal or glass pipettes filled with electrically conductive solutions.

Question 59

Molecular mimicry

Answer 59

Sequence similarities between viral peptides and self-peptides that result in the cross-activation of autoreactive T or B cells by virus-derived peptides. (Chapters 5 and 8) // The similarity between some pathogen antigens and host antigens, such that antibodies and T cells produced against the former also react against host tissues. This similarity may be the cause of some autoimmunity.

Question 60

multidrug resistance (MDR) protein

Answer 60

Type of ABC transporter protein that can pump hydrophobic drugs (such as some anticancer drugs) out of the cytoplasm of eukaryotic cells.

Question 61

NAD, NADP (nicotinamide adenine dinucleotide, nicotinamide adenine dinucleotide phosphate)

Answer 61

Two cosubstrates that accept or donate electrons (+ proton) in many dehydrogenase reactions. // Nicotinamide-containing coenzymes functioning as carriers of hydrogen atoms and electrons in some oxidation-reduction reactions.

Question 62

Neuraminidase

Answer 62

An enzyme present on the surface of viral particles that cleaves the bond holding the newly formed viral particles to host cells. // An influenza virus protein that cleaves sialic acid from host cells to allow viral detachment, a common antigenic determinant, and target of antiviral neuraminidase inhibitors.

Question 63

Nitrous acid

Answer 63

HNO2, a potent chemical mutagen. // The acid form of the nitrites; causes mutations by deaminating DNA bases.

Question 64

nonsense codon

Answer 64

A codon that does not encode any amino acid. // A codon that does not specify an amino acid, but signals the termination of a polypeptide chain.

Question 65

oligodendrocyte

Answer 65

(ol′i-gō-den′drō- sı̄t) Category of large glial cells in the central nervous system that wrap around and insulate axons. // Glial cell in the vertebrate central nervous system that forms a myelin sheath around axons. Compare Schwann cell.

Question 66

organic chemistry

Answer 66

The study of carbon-based compounds.

Question 67

Osteoporosis

Answer 67

Brittle, fragile bones in elderly people. // (os′tē-ō-pō-rō′sis) Medical condition characterized by decreased bone mass and increased susceptibility to fracture.

Question 68

Paralogous genes

Answer 68

Homologous genes present within a species (cf. Homologous genes).

Question 69

Pellagra

Answer 69

Niacin deficiency; symptoms include dermatitis, diarrhea, and dementia. // Disease caused by a niacin deficiency in which diarrhea, dermatitis, dementia, and, eventually, death, can result.

Question 70

persistent viral infection // persistent infection

Answer 70

A viral infection that is not cleared by the combined actions of the innate and adaptive immune response. // A disease process that occurs gradually over a long period.

Question 71

photolyase

Answer 71

An enzyme that splits thymine dimers in the presence of visible light. // Repair enzyme that reverse cross-linking between DNA bases by the use of blue and UV-Alight.

Question 72

phytoplankton

Answer 72

Free-floating photoautotrophs. // Autotrophic members of plankton community.

Question 73

polar covalent bond

Answer 73

A covalent bond between two atoms with significantly different electronegativities, resulting in an uneven distribution of electron density. // A covalent bond in which the electron distribution between atoms is unsymmetrical.

Question 74

polysome

Answer 74

A complex of an mRNA molecule and two or more ribosomes; also called polyribosome. polyunsaturated fatty acid See PUFA. // An mRNA bound to multiple ribosomes that are synthesizing proteins from the mRNA template. (Chapter 11)

Question 75

power

Answer 75

The quick application of force against resistance. This unit of work is expressed per unit of time (i.e., power = work/time) and is often considered a factor of intensity. It may also be calculated by multiplying force 3 displacement. // Th e probability that a meaningful diff erence or eff ect can be detected, if one were to occur. (Chapter 1)

Question 76

propeptides

Answer 76

Inactive precursor form of a polypeptide or peptide, which requires proteolytic processing to produce the active peptide. // The N- and C-terminal extensions in procollagen.

Question 77

Quadrupole (Q)MS // Quadrupole mass analyzer

Answer 77

Mass analyzer in mass spectrometry separating ions by their transmission, traversing an electrodynamic field. // A type of mass spectrometer that uses four cylindrical rods to create an oscillating electrostatic ield. Ion trajectories are determined by their m/z ratios. At a given ield, only one m/z value will make it through the quadrupole region—the others will crash into the quadrupole rods or the walls of the instrument and never reach the detector.

Question 78

receptor serine/threonine kinase

Answer 78

Cell-surface receptor with an extracellular ligand-binding domain and an intracellular kinase domain that phosphorylates signaling proteins on serine or threonine residues in response to ligand binding. The TGFβ receptor is an example. // Receptors that have an intrinsic serine/threonine kinase activity in their cytoplasmic tails.

Question 79

reduction division

Answer 79

Phase of meiosis in which the maternal and paternal chromosomes of the bivalent separate (cf. Equational division). // The process in meiosis I where maternal and paternal pairs of homologous chromosomes are separated and move to opposite ends of the cell.

Question 80

replisome

Answer 80

The multiprotein complex that promotes DNA synthesis at the replication fork. // The complete replication apparatus—present at a replication fork—that carries out the semiconservative replication of DNA.

Question 81

response element

Answer 81

A region of DNA, near (upstream from) a gene, that is bound by specific proteins that influence the rate of transcription of the gene. // A regulatory DNA sequence that mediates the effects of a hormone, second messenger, nutrient, or metabolite on gene transcription.

Question 82

ribose

Answer 82

A five-carbon monosaccharide that serves as a component of RNA, DNA, and ATP. // A five-carbon sugar that is part of ribonucleotide molecules and RNA.

Question 83

Satellite band

Answer 83

A band formed by DNA in a density gradient that is smaller than, and distinct from, main-band DNA. A satellite band contains repeated DNA sequences called satellite DNAs with lower or higher densities than main-band DNA.

Question 84

second law of thermodynamics

Answer 84

A law stating that for any spontaneous process, the entropy of the universe increases (ΔSuniv > 0). // The law stating that, in any chemical or physical process, the entropy of the universe tends to increase.

Question 85

serine protease

Answer 85

Type of protease that has a reactive serine in the active site. // One of four major classes of proteases, featuring a reaction mechanism in which an active-site Ser residue acts as a covalent catalyst.

Question 86

signal peptidase

Answer 86

Enzyme that removes a terminal signal sequence from a protein once the sorting process is complete. // An enzyme in the endoplasmic reticulum that cleaves off the signal sequence.

Question 87

site-specific recombination

Answer 87

A type of genetic recombination that occurs only at specific sequences. // Exchange of DNA sequences at short DNA sequences that are specifically recognized by proteins that catalyze recombination. (Chapter 9)

Question 88

specific rotation, [α]D

Answer 88

The rotation, in degrees, of the plane of plane-polarized light (D-line of sodium) by an optically active compound at 25 8C, with a specified concentration and light path. // The optical rotation of a chiral compound under standard conditions.

Question 89

spontaneous mutation

Answer 89

A mutation that occurs without a mutagen. // A mutation that occurs without a known cause (cf. Induced mutation).

Question 90

stimulatory G protein (Gs)

Answer 90

A trimeric regulatory GTP-binding protein that, when activated by an associated plasma membrane receptor, stimulates a neighboring membrane enzyme such as adenylyl cyclase. Its effects oppose those of Gi. // G protein that, when activated, activates the enzyme adenylyl cyclase and thus stimulates the production of cyclic AMP. See also G protein.

Question 91

suppressor mutation

Answer 91

A mutation that totally or partially restores a function lost by a primary mutation; located at a site different from the site of the primary mutation. // A mutation that partially or completely cancels the phenotypic effect of another mutation.

Question 92

tau // Tau protein

Answer 92

Abnormal protein in the neurofibrillary tangles present in Alzheimer’s disease. // An axonal protein that is misfolded in many neurodegenerative diseases.

Question 93

testosterone

Answer 93

The predominant male sex hormone, which is produced in the testes in men and the adrenal cortex and ovaries in women. Testosterone is often used as an index of anabolism or the anabolic status of the body. // A steroid hormone that induces the development of male characteristics.

Question 94

TH2 cell

Answer 94

A type of effector helper T cell that helps activate B cells to produce antibodies, to undergo somatic hypermutation, and switch the class of immunoglobulin produced.

Question 95

tocopherol

Answer 95

Any of several forms of vitamin E. topoisomerases Enzymes that introduce positive or negative supercoils in closed, circular duplex DNA. // A class of vitamin E molecules with saturated phytyl side chains.

Question 96

Transformation (cancerous)

Answer 96

The conversion of eukaryotic cells growing in culture to a state of uncontrolled cell growth (similar to tumor cell growth).

Question 97

transmembrane protein

Answer 97

Membrane protein that extends through the lipid bilayer, with part of its mass on either side of the membrane.

Question 98

two-dimensional gel electrophoresis

Answer 98

Technique combining two different separation procedures—separation by charge (isoelectric focusing) in the first dimension, then separation by size in a direction at a right angle to that of the first step—to resolve up to 2000 proteins in the form of a two-dimensional protein map. // Analytical method most frequently used in proteomics for separation of proteins in an electric field according to two basic protein properties, their charge depending on the amino acid composition and their size depending on the number of amino acids.

Question 99

urinalysis

Answer 99

(ū-ri-nal′i-sis) Analysis of the urine to help assess the state of a person’s health. // Semiquantitative determination of urinary metabolites.

Question 100

variable region

Answer 100

Region of an immunoglobulin or T cell receptor polypeptide chain that is the most variable and contributes to the antigen-binding site. // The region of an immunoglobulin or T-cell receptor that is formed of the amino-terminal domains of its component polypeptide chains. These are the most variable parts of the molecule and contain the antigenbinding sites.

Question 101

Vitamin K

Answer 101

A fat-soluble vitamin that is required for the synthesis of blood clotting factors. // Accepted designation for activity preventing hypoprothrombinemic hemorrhage shared by related naphthoquinones

Question 102

wobble

Answer 102

The relatively loose base pairing between the base at the 3’ end of a codon and the complementary base at the 5’ end of the anticodon. // Freedom of base-pairing between the third codon base and the first anticodon base.

Question 103

zwitterion

Answer 103

A dipolar ion with spatially separated positive and negative charges. // A molecule that contains at least one positive and at least one negative charge.