BIO - TERMS - FREQUENCY > 1 PT 10 Flashcards
acetyl CoA carboxylase
The rate-limiting enzyme of fatty acid biosynthesis. // A key enzyme that begins fatty acid synthesis by catalyzing the carboxylation of acetyl CoA to produce malonyl CoA.
adenosine diphosphate (ADP)
(ADP)—A high-energy phosphate compound that can be used to form ATP. // The substance formed when ATP is hydrolyzed and energy is released.
alanine cycle // alanine–glucose cycle
Cycling of alanine and glucose between muscle and liver during fasting. // A series of reactions between muscle and the liver, whereby amino acids in the muscle are converted to alanine, which is transported via the blood to the liver, where the alanine is converted first to pyruvate and then to glucose, which can then circulate back to muscle.
alpha (α) particle
A particle released during alpha decay; equivalent to a helium-4 nucleus.
ampulla
The bulge along a semicircular canal, which contains the hair cells that transduce rotation. // (am-pul′lă; pl., ampullae, -lē) Saccular dilation of a canal or duct, such as the ductus deferens in the male reproductive system.
antibonding MO // antibonding orbital
A molecular orbital that is higher in energy than the atomic orbitals from which it is formed. // A molecular orbital that is higher in energy than any of the atomic orbitals from which it was formed.
apoenzyme
The protein portion of an enzyme, which requires activation by a coenzyme. // The protein portion of an enzyme, exclusive of any organic or inorganic cofactors or prosthetic groups that might be required for catalytic activity.
ataxia telangiectasia (ATM)
A syndrome that is caused by impaired repair of DNA double-strand breaks. // A disease characterized by a staggering gait and multiple disorganized blood vessels, and often accompanied by clinical immunodeficiency. It is caused by defects in the ATM protein, which is involved in DNA repair pathways that are also used in V(D)J recombination and class-switch recombination.
autonomic nervous system (ANS)
The part of the nervous system that regulates processes that occur below the conscious level; i.e., the activity of cardiac muscle, smooth muscle, and glands. // A system of central and peripheral nerves that innervates the internal organs, cardiovascular system, and glands; also called visceral PNS. The ANS consists of sympathetic, parasympathetic, and enteric divisions.
bacterial artificial chromosome (BAC)
Cloning vector that can accommodate large pieces of DNA, typically up to 1 million base pairs. // Cloning vectors constructed from bacterial fertility (F) factors; like YAC vectors, they accept large inserts of size 200 to 500 kb.
Bile acids
Emulsifiers in bile; required for lipid absorption. // Polar derivatives of cholesterol, secreted by the liver into the intestine, that serve to emulsify dietary fats, facilitating lipase action on them.
body mass index (BMI)
Weight/height2. // An index of a person’s weight in relation to height; determined by dividing the weight (in kilograms) by the square of the height (in meters). body weight The total mass of a person, expressed in pounds (lb) or kilograms (kg).
calreticulin
Carbohydrate-binding chaperone protein in the endoplasmic reticulum (ER) lumen that binds to oligosaccharides on incompletely folded proteins and retains them in the ER. // A chaperone protein in the endoplasmic reticulum that, together with ERp57 and tapasin, forms the peptide-loading complex that loads peptides onto newly synthesized MHC class I molecules.
cardiac output (CO), Q
The volume of blood pumped by the heart per minute. Calculated as stroke volume multiplied by heart rate. // Volume of blood ejected by the ventricle in 1 minute; calculated by multiplying heart rate times stroke volume.
central memory T cells (TCM)
Self-renewing memory T cells that are abundant in lymph nodes and other lymphoid tissues. (Chapter 4) // Memory lymphocytes that express CCR7 and recirculate between blood and secondary lymphoid tissues similarly to naive T cells. They require restimulation in secondary lymphoid tissues to become fully mature effector T cells.
chemistry
The science of the interactions between atoms and molecules. // The science that seeks to understand the behavior of matter by studying the behavior of atoms and molecules.
Cholera toxin
The enterotoxin of Vibrio cholerae. // Secreted toxic protein of Vibrio cholerae responsible for causing the watery diarrhea associated with cholera. Comprises an A subunit with enzymatic activity and a B subunit that binds to host-cell receptors to direct subunit A to the host-cell cytosol.
Clathrin
The protein that forms the coat of coated vesicles. // Protein that assembles into a polyhedral cage on the cytosolic side of a membrane so as to form a clathrin-coated pit, which buds off by endocytosis to form an intracellular clathrin-coated vesicle.
commissure
Any collection of axons that connect one side of the brain with the other side. // (kom′i-shūr) Bundle of axons passing from one side to the other in the brain or spinal cord.
conjugate base
Any acid from which a proton has been removed. // The product that results from deprotonation of a Brønsted–Lowry acid.
continuous cell line
Cultures of a single cell type that can be propagated indefinitely in culture. (Chapter 2) // Animal cells that can be maintained through an indefinite number of generations in vitro.
crRNA
Small noncoding RNAs (≈30 nucleotides) that are the effectors of CRISPR-mediated immunity in bacteria. // A short RNA derived from the spacers within the CRISPR arrays in the genomes of bacteria and archaea. See Clustered regularly interspersed palindromic repeats (CRISPR).
defensins
Small peptide antibiotics made by human cells. // Small (29- to 51- residue), cysteine-rich, cationic proteins produced by lymphocytes and epithelial cells that are active against bacteria, fungi, and enveloped viruses; usually found in the gut. (Chapter 2)
diabetes insipidus
Disease involving reduced ADH release or reduced kidney response to ADH; leads to excessive urine production. // A condition characterized by extreme water loss leading to extreme thirst. Normally caused by the lack of antidiuretic hormone.
dipole–dipole force
Noncovalent electrostatic interactions between dipolar molecules. // An intermolecular force exhibited by polar molecules that results from the uneven charge distribution.
DNA methylation
A covalent modification of DNA that suppresses transcription. // Addition of methyl groups to DNA. Extensive methylation of the cytosine base in CG sequences is used in plants and animals to help keep genes in an inactive state.
dura mater
(dū′ră mah′ter) Tough, fibrous membrane forming the outer meningeal layer of the central nervous system. // The outermost of the three meninges, the membranes that cover the surface of the central nervous system.
Elastin
The major component of elastic fibers. // Extracellular protein that forms extensible fibers (elastic fibers) in connective tissues.
Electrostatic interaction
“Salt bond”; the attraction force between oppositely charged ions. // Chemical interaction occurring between charged atoms, as in the charged amino acid side chains and an ion in a salt bridge.
endothelium
(en-dō-thē′lē-ŭm) The simple squamous epithelium that lines the lumen of blood vessels, lymphatic vessels, and heart chambers and valves. // The epithelium that forms the walls of blood capillaries and the lining of larger blood vessels.
Erythropoietin
A kidney-derived growth factor that stimulates erythropoiesis in the bone marrow. // A hormone produced by the kidney that stimulates the production of red blood cells in bone marrow.
extracellular polymeric substance (EPS)
A glycocalyx that permits bacteria to attach to various surfaces. // Hydrated biopolymers (proteins, polysaccharides, extracellular DNA) which form thematrix inwhich biofilmcells are immobilized.
fertilization
(fer′til-i-zā′shŭn) Process of sperm penetration of the secondary oocyte. // The fusion of a male gamete (sperm) with a female gamete (egg) to form a zygote.
flexion
The direction of movement that closes a joint. // (flek′shŭn) Movement of a joint in an anterior-posterior plane that decreases the angle between the articulating bones.
free radical
An unstable formof oxygen molecule that can damage cells. // A molecule or ion with an odd number of electrons in its Lewis structure.
gamma globulin
The serum fraction containing immunoglobulins (antibodies); also called immune serum globulin.
genetic map
A diagram showing the relative sequence and position of specific genes along a chromosome. // A diagram of a chromosome with distances based on recombination frequencies—centiMorgans.
glycerophospholipid
Lipids that contain a glycerol backbone linked to two fatty acids and a phosphoric acid. // An amphipathic lipid with a glycerol backbone; fatty acids are esterlinked to C-1 and C-2 of glycerol, and a polar alcohol is attached through a phosphodiester linkage to C-3.
GPCR kinase (GRK)
Member of a family of enzymes that phosphorylates multiple serines and threonines on a GPCR to produce receptor desensitization. // A family of protein kinases that phosphorylate Ser and Thr residues near the carboxyl terminus of G protein–coupled receptors, initiating their internalization.
growth cone
The specialized tip of a growing neurite. // Migrating motile tip of a growing nerve cell axon or dendrite.
hematopoiesis
The formation of blood cells. // (hē′mat′ō-poy-ē′sis) Formation and development of blood cells.
heterotroph
An organism that requires an organic carbon source; also called organotroph. // An organism that requires complex nutrient molecules, such as glucose, as a source of energy and carbon.
hyaluronic acid
A glycosaminoglycan found in joints. // A large, unsulfated glycosaminoglycan (GAG), not bound to a core protein.
hyper IgE syndrome (HIES)
Also called Job’s syndrome. A disease characterized by recurrent skin and pulmonary infections and high serum concentrations of IgE.
Hypothesis
In science, a statement about how a phenomenon can be explained. // A tentative interpretation or explanation of an observation; a good hypothesis is falsifiable.
immunotherapy
Making use of the immune system to attack tumor cells, either by enhancing the normal immune response or by using toxin-bearing specific antibodies. See also immunotoxin. // A treatment that provides an infected host with exogenous antiviral cytokines, other immunoregulatory agents, antibodies, or lymphocytes in order to reduce viral pathogenesis. (Chapter 8)
induced fit
A change in the conformation of an enzyme in response to substrate binding that renders the enzyme catalytically active; also used to denote changes in the conformation of any macromolecule in response to ligand binding such that the binding site of the macromolecule better conforms to the shape of the ligand. // A principle for increasing the specificity of substrate recognition by proteins and RNAs. In protein synthesis, a ribosome, or enzyme folds around a codon– anticodon interaction and only when the match is correct is the subsequent reaction allowed to proceed.
innate immune response
An early immune response in all organisms to a pathogen, which includes the production of antimicrobial molecules and the activation of phagocytic cells. Such a response is not specific for the pathogen, in contrast to an adaptive immune response.
Interference
Crossing over at one point that reduces the chance of another crossover nearby; detected by studying the pattern of crossing over with three or more linked genes. // The superposition of two or more waves overlapping in space, resulting in either an increase in amplitude (constructive interference) or a decrease in amplitude (destructive interference).
IκB
Inhibitory proteins that bind tightly to NFκB dimers and hold them in an inactive state within the cytoplasm of unstimulated cells. // A cytoplasmic protein that constitutively associates with the NFκB homodimer, composed of p50 and p65 subunits. When IκB is phosphorylated by activated IKK (IκB kinase), IκB becomes degraded and allows the NFκB dimer to be released as an active transcription factor.
lactate
Chemical produced during glycolysis. // A salt formed from lactic acid. Lactate is not believed to be associated with fatigue but can be used to create energy.
lectin pathway
Complement activation pathway that is triggered by mannose-binding lectins (MBLs) or ficolins bound to bacteria. // One of three complement pathways that lead to activation of C3-C5 convertases; mannose-binding, lectin-associated proteases cleave the C2 and C4 proteins. (Chapter 3)
lignin
A noncarbohydrate component of insoluble dietary fiber composed of aromatic polymers. // Network of cross-linked phenolic compounds that forms a supporting network throughout the cell walls of xylem and woody tissue in plants.
Long terminal repeats
The terminal repeat sequences of retroviral cDNAs. // Identical or nearly identical DNA sequences at opposite ends of an integrated retrovirus or a retroviruslike element. Typically these sequences are at least 300 base pairs in length. Abbreviation: LTRs.
malignant
(mă-lig′nant) In reference to a neoplasm, having the property of invasiveness and spread. // Of tumors and tumor cells: invasive and/or able to undergo metastasis. A malignant tumor is a cancer.
metabotropic receptor
A G-protein-coupled receptor whose primary action is to stimulate an intracellular biochemical response. // Neurotransmitter receptors that regulate ion channels indirectly through the activation of second-messenger molecules.
microarray
DNA probes attached to a glass surface, used to identify nucleotide sequences in a sample of DNA. // A membrane or other solid support containing thousands of oligonucleotides or nucleic acid hybridization probes for use in detecting complementary DNAs or RNAs.
mole fraction (χₐ) // (χsolute)
The number of moles of a component in a mixture divided by the total number of moles in the mixture. // A means of expressing solution concentration as the number of moles of solute per moles of solution.
multidrug resistance
An observed phenomenon in which cells exposed to one anticancer drug evolve a resistance not only to that drug, but also to other drugs to which they have never been exposed.
myoblast
(mı̄′ō-blast) Undifferentiated muscle cell with the potential of becoming a muscle fiber. // Mononucleated, undifferentiated muscle precursor cell. A skeletal muscle cell is formed by the fusion of multiple myoblasts.
neural tube
The primitive embryonic central nervous system, consisting of a tube of neural ectoderm. // Tube of ectoderm that will form the brain and spinal cord in a vertebrate embryo.
nitrogen cycle
The series of processes that converts nitrogen (N2) to organic substances and back to nitrogen in nature. // The cycling of various forms of biologically available nitrogen through the plant, animal, and microbial worlds, and through the atmosphere and geosphere.
nonpolar // nonpolar molecules
Hydrophobic; describes molecules or groups that are poorly soluble in water. // Molecules containing nonpolar covalent chemical bonds; hydrophobic.
olfaction
(ol-fak′shŭn) Sense of smell.
orbital diagram
A diagram that gives information similar to an electron configuration but symbolizes an electron as an arrow in a box representing an orbital, with the arrow’s direction denoting the electron’s spin.
osteocyte
(os′tē-ō-sı̄t) Bone cell in a lacuna within bone matrix. // Nondividing cell in bone that develops from an osteoblast and is embedded in bone matrix.
Paracrine signaling
The action of an extracellular messenger on neighboring cells within its tissue of origin. // Short-range cell–cell communication via secreted signal molecules that act on neighboring cells.
pectin
Mixture of polysaccharides rich in galacturonic acid which forms a highly hydrated matrix in which cellulose is embedded in plant cell walls. // A polysaccharide composed of repeating methylated or nonmethylated galacturonic acid subunits covalently bonded with a b1–4 linkage.
Peroxisome proliferator-activated receptors (PPARs)
Nuclear receptors that regulate lipid and carbohydrate metabolism. // A family of nuclear transcription factors, activated by lipidic ligands, that alter the expression of specific genes, including those encoding enzymes of lipid synthesis and breakdown.
photochemical reaction center
The part of a photosynthetic complex where the energy of an absorbed photon causes charge separation, initiating electron transfer. // The part of a photosystem that converts light energy into chemical energy in photosynthesis.
phytochrome
Plant photoprotein that senses light via a covalently attached light-absorbing chromophore, which changes its shape in response to light and then induces a change in the protein’s conformation. Plant phytochromes are dimeric, cytoplasmic serine/threonine kinases, which respond differentially and reversibly to red and far-red light to alter cell behavior. // Red/far-red light photoreceptors that use a linear tetrapyrrole as chromophore; phytochromes normally exist as two stable conformers, the redlight- absorbing Pr- and the far-red light-absorbing Pfr-form.
platelet-activating factor (PAF)
A lipid mediator that activates the blood clotting cascade and several other components of the innate immune system. // A soluble, biologically active phosphoglyceride released from white blood cells.
polysaccharide capsules
A distinct structure in some bacteria—both Gram-negative and Gram-positive—that lies outside cell membrane and cell wall that can prevent direct phagocytosis by macrophages without the aid of antibody or complement. // Carbohydrate coverings with antigenic specificity that are present on some types of bacteria.
potential energy
Stored energy. // The energy associated with the position or composition of an object.
prokaryotic species
A population of cells that share certain rRNA sequences; in conventional biochemical testing, it is a population of cells with similar characteristics.
pyrimidine dimer
A covalently joined dimer of two adjacent pyrimidine residues in DNA, induced by absorption of UV light; most commonly derived from two adjacent thymines (a thymine dimer). // A DNA lesion caused by ultraviolet radiation.
receptor editing
Process by which a developing B cell that recognizes a self molecule changes its antigen receptors so that the cell no longer does so. // The replacement of a light or heavy chain of a selfreactive antigen receptor on immature B cells with a newly rearranged chain that does not confer autoreactivity.
reducing sugar
A sugar in which the carbonyl (anomeric) carbon is not involved in a glycosidic bond and can therefore undergo oxidation. // Sugars that reduce silver ion in the Tollens test or cupric ion in the Fehling or Benedict tests.
Replicon
A unit of replication in large genomes, defined by discrete origin and termini. (Chapter 9) // A unit of replication. In bacteria, replicons are associated with segments of the cell membrane that control replication and coordinate it with cell division.
respiratory quotient (RQ)
The ratio of respiratory CO2 produced to O2 consumed. // Ratio of carbon dioxide produced and oxygen consumed at the cell or tissue level. resting energy expenditure (REE) Is similar to basal metabolic rate and is the calories expended while at rest; but the subject does not have to be fasting as one does for basal metabolic rate.
Rheb
A small GTPase that activates mTOR when in its GTP-bound form, and is inactivated by a GTPase-activating protein (GAP) complex TSC1/2. rheumatic fever Disease caused by antibodies elicited by infection with some Streptococcus species. These antibodies cross-react with kidney, joint, and heart antigens. // A monomeric Ras-related GTPase that in its active form (Rheb-GTP) activates mTOR, which promotes cell growth.
sarcoma
Cancer of connective tissue. // Malignant connective tissue tumor.
Sec61 // Sec61 complex
A multisubunit transmembrane protein pore complex that resides in the membrane of the endoplasmic reticulum and allows peptides to be translocated from the ER lumen into the cytoplasm. // Three-subunit core of the protein translocator that transfers polypeptide chains across the endoplasmic reticulum membrane.
septic shock
Systemic shock reaction that can follow infection of the bloodstream with endotoxin-producing Gram-negative bacteria. It is caused by the systemic release of TNF-α and other cytokines. Also called endotoxic shock. // A sudden drop in blood pressure induced by bacterial toxins.
sigma (σ) bond
The resulting bond that forms between a combination of any two s, p, or hybridized orbitals that overlap end to end. // A covalent bond formed by headon overlap of atomic orbitals.
Sister chromatid
One of the products of chromosome duplication. // Tightly linked pair of chromosomes that arise from chromosome duplication during S phase. They separate during M phase and segregate into different daughter cells.
species
The most specific level in the taxonomic hierarchy. See also bacterial species; eukaryotic species; viral species. // Interbreeding, natural populations that are reproductively isolated from other such groups.
spinal cord
Bundle of neurons and support cells that extends from the brain. // The part of the central nervous system in the vertebral column.
sterol regulatory element-binding protein (SREBP)
A transcription factor that has several isoforms, all of which are involved in lipid or cholesterol biosynthesis. // A cholesterolregulated transcription factor.
superoxide radical
A toxic anion (O2-) with an unpaired electron. // A free radical formed by the transfer of a single electron to molecular oxygen.
Taq polymerase
A heat-stable DNA polymerase isolated from the thermophilic bacterium Thermus aquaticus. // A heat-stable DNA polymerase used for polymerase chain reaction (PCR).
terminator
Signal in bacterial DNA that halts transcription; in eukaryotes, transcription terminates after cleavage and polyadenylation of the newly synthesized RNA. // The site on a DNA strand at which transcription ends.
TH2
A subset of effector CD4 T cells that are characterized by the cytokines they produce. They are involved in stimulating B cells to produce antibody, and are often called helper CD4 T cells.
titration
A laboratory procedure in which a substance in a solution of known concentration is reacted with another substance in a solution of unknown concentration in order to determine the unknown concentration; see also acid–base titration. // Treatment of a weak acid or base with a strong base or acid, respectively.
transcriptional control
The regulation of a protein’s synthesis by regulation of the formation of its mRNA. // Regulation by a cell of gene expression by controlling when and how often a given gene is transcribed.
transmembrane adhesion proteins
Cytoskeletonlinked transmembrane molecules with one end linking to the cytoskeleton inside the cell and the other end linking to other structures outside it.
tumor progression
Process by which an initial mildly disordered cell behavior gradually evolves into a full-blown cancer. // The progressive accumulation of oncogenic mutations in neoplastic cells.
uric acid
The end product of purine degradation. // Nitrogenous waste produced from breakdown of nucleic acids; eliminated in urine.
van der Waals interaction
Weak intermolecular forces between molecules as a result of each inducing polarization in the other. // Weak attractions between atoms placed in close proximity.
Vitamin B2 complex
Obsolete term for the thermostable “second nutritional factor” in yeast, which was found to be a mixture of niacin, riboflavin, pyridoxine, and pantothenic acid
white matter
A generic term for a collection of central nervous system axons. When a freshly dissected brain is cut open, axons appear white. See also gray matter. // Brain or spinal cord tissue that derives its color from myelin in myelinated axons.
zoonotic
Describes a disease of animals that can be transmitted to humans. // Transmitted among humans and other vertebrates; refers to infections and diseases. (Chapter 1)
